Module 2 (Chapters 5 – 8) focuses on sex, gender, sexuality, sensation and perception, learning, and memory. Respond to the following questions by writing one full paragraph (100 word minimum) for each numbered question:
1. What was your overall impression with the information presented in the chapters contained in this module? For example, was it challenging, fascinating, did it make you question your previous assumptions, etc.
2. Name three concepts that you found to be of particular interest in this module. Why were they of special interest to you?
3. How do you think the information in this module applies to your life?
Sex, Gender, and Sexuality
Chapter 5
EXPLORING PSYCHOLOGY
DAVID G. MYERS | C. NATHAN DEWALL
Gender Development
Sex
In psychology, the biologically influenced characteristics by which people define males and females.
Gender
In psychology, the socially influenced characteristics by which people define men and women.
Gender is the product of the interplay among our biological dispositions, our developmental experiences, and our current situations.
Some traits may be genetic differences; other role differences may be nurtured by culture.
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How Are We Alike? How Do We Differ?
(part 1)
Each person receives 23 chromosomes from the mother and 23 from the father.
Of these 46 chromosomes, 45 are shared by men and women.
Some similarities:
Creativity, intelligence, emotions
Our “opposite” sex is, in reality, our very similar sex.
Some differences:
Self-esteem
Puberty age
Emotional expression
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How Are We Alike? How Do We Differ?
(part 2)
Aggression
Any physical or verbal behavior intended to harm someone physically or emotionally
Relational aggression
An act of aggression (physical or verbal) intended to harm a person’s relationship or social standing
How Are We Alike? How Do We Differ?
(part 3)
Aggression
Minor physical aggression in romantic relationships: Men and women are roughly equal.
Extreme violent acts: Men commit far more often than women.
Relational aggression: Women commit slightly more often than men.
How Are We Alike? How Do We Differ?
(part 4)
Social connectedness
Boys and men are often independent; girls and women are often interdependent.
Men tend to connect perception with action; women tend to improve social relationships.
Men often prefer working with things; women often prefer working with people.
Men are more often driven by money and status; women often opt for fewer work hours and tend to have greater responsibility for family obligations.
Women more often support others; they “tend and befriend.”
The gender gap subsides by age 50.
The Nature of Gender: Biological Sex
Biology does not dictate gender, but it can influence it in two ways:
Genetically: Males and females have differing sex chromosomes.
Physiologically: Males and females have differing concentrations of sex hormones, which trigger other anatomic differences.
Prenatal Sexual Development (part 1)
Prenatal sexual development
Contribution to 23rd chromosome pair:
Mother = X chromosome
Father = X or Y chromosome
Around 7th week: Y chromosome prompts testes to develop and produce testosterone
Between 4th and 5th months: Sex hormones in fetal brain support female or male wiring
Prenatal Sexual Development (part 2)
X chromosome
Sex chromosome found in both men and women
Y chromosome
Sex chromosome found only in males
Testosterone
Both males and females have it, but females have less.
The additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of male sex characteristics during puberty.
Females have two X chromosomes; males have one X and one Y.
An X chromosome from each parent produces a female child.
When a Y chromosome is paired with an X chromosome from the mother, it produces a male child.
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Adolescent Sexual Development (part 1)
During adolescence, boys and girls enter puberty and mature sexually.
Puberty: A period of sexual maturation, during which a person becomes capable of reproducing.
Pronounced physical differences emerge.
A surge of hormones triggers a two-year period of rapid physical development.
Primary and secondary sex characteristics develop dramatically.
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Height Differences
Throughout childhood, boys and girls are similar in height.
At puberty, girls surge ahead briefly, but then boys overtake them at about age 14.
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Adolescent Sexual Development (part 2)
Primary sex characteristics
Body structures (ovaries, testes, and external genitalia) that make sexual reproduction possible
Secondary sex characteristics
Nonreproductive sexual traits, such as female breasts and hips, male voice quality, and body hair
Spermarche
First ejaculation
Menarche
First menstrual period
Body Changes at Puberty
At about age 11 in girls and age 12 in boys, a surge of hormones triggers a variety of physical changes.
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I Am Who I Am
Disorder of sexual development: A condition present at birth that involves unusual development of sex chromosomes and anatomy
Sex reassignment surgery: More common in the past; can create distress
Dramatic improvements in South African track star Caster Semenya’s race times prompted the International Association of Athletics Federations to undertake sex testing in 2009. Semenya was reported to have a disorder of sexual development, with physical characteristics not typically male or female. She was officially cleared to continue competing as a woman. Semenya declared, “God made me the way I am and I accept myself. I am who I am” (YOU, 2009).
Sex-related genes and physiology “result in behavioral and cognitive differences between males and females” (NAS, 2001). Yet environmental factors matter as well.
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The Nurture of Gender: Our Culture and
Experiences (part 1)
Gender role
A role is a set of expectations (norms) about a social position
A gender role is a set of expected behaviors, attitudes, and traits for males or for females
Gender identity
Our gender identity is our personal sense of being male, female, or some combination of the two
The Nurture of Gender: Our Culture and Experiences (part 2)
Gender roles shift over time in history.
A century ago, American women could not vote in national elections, serve in the military, or divorce a husband without cause.
Gender roles vary from one place to another.
Nomadic societies of food-gathering people have little division of labor by sex.
Agricultural societies, in which women typically work in the nearby fields and men roam while herding livestock, assume more distinct gender roles.
How Do We Learn Gender? (part 1)
How do we learn our gender identity—our personal sense of being male, female, or, occasionally, some combination of the two?
Social learning theory: Proposes social behavior is learned by observing and imitating others’ gender-linked behavior and by being rewarded or punished.
Gender typing: The acquisition of a traditional masculine or feminine role. It varies from child to child, which indicates there is more to gender typing than solely observation and imitation.
How Do We Learn Gender? (part 2)
Learning to be male or female involves feeling AND thinking.
Formation of schemas helps children make sense of their world.
Gender schemas form early in life and organize experiences of male–female characteristics.
Gender expression can be seen as children drop hints in their language, clothing, interests, and possessions.
How Do We Learn Gender? (part 3)
Androgyny
Displaying both traditional masculine and feminine psychological characteristics
Transgender
Umbrella term describing people whose gender identity or expression differs from that associated with their birth sex
Hormones and Sexual Behavior (part 1)
Asexuality is having no sexual attraction to others.
Sex hormones are one of the forces that drive sexual behavior.
Testosterone: Most important male sex hormone
It is found in both males and females.
The additional testosterone in males stimulates growth of the male sex organs during fetal period, and development of the male sex characteristics during puberty
Estrogens: Sex hormones, such as estradiol, that are secreted in greater amounts by females than by males and contribute to female sex characteristics
In nonhuman female mammals, estrogen levels peak during ovulation, promoting sexual receptivity.
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Hormones and Sexual Behavior (part 2)
Large hormonal surges or declines tend to occur at two predictable points in the life span.
The pubertal-stage surge triggers development of sex characteristics and sexual interest.
In later life, hormone levels fall, with women experiencing menopause and men a more gradual change.
A third point sometimes occurs.
For some people, surgery or drugs may cause hormonal shifts.
The Sexual Response Cycle (part 1)
The sexual response cycle includes four stages of sexual responding as identified by William Masters and Virginia Johnson (1966):
Excitement
Plateau
Orgasm
Resolution
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The Sexual Response Cycle (part 2)
Excitement: The genital areas become engorged with blood, causing a woman’s clitoris and a man’s penis to swell. A woman’s vagina expands and secretes lubricant; her breasts and nipples may enlarge.
Plateau: Excitement peaks as breathing, pulse, and blood pressure rates continue to increase. Some fluid—frequently containing enough live sperm to enable conception—may appear at the tip of the penis. A woman’s vaginal secretion continues to increase, and her clitoris retracts. Orgasm feels imminent.
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The Sexual Response Cycle (part 3)
Orgasm: Muscle contractions appear all over the body and are accompanied by further increases in breathing, pulse, and blood pressure rates. The pleasurable feeling of sexual release is much the same for both sexes.
Resolution: The body gradually returns to its unaroused state as the genital blood vessels release their accumulated blood. Men then enter a refractory period that lasts from a few minutes to a day or more, during which they are incapable of another orgasm. A woman’s much shorter refractory period may enable her, if restimulated during or soon after resolution, to have more orgasms.
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Sexual Dysfunctions and Paraphilias (part 1)
Sexual dysfunctions
Impair sexual arousal or functioning
Often involve sexual motivation, especially sexual motivation and arousal
Males: Include erectile disorder and premature ejaculation
Females: Include female orgasmic disorder and female sexual interest/arousal disorder
Sometimes involve paraphilias—sexual desire directed in unusual ways (e.g., pedophilia, exhibitionism)
Sexual Dysfunctions and Paraphilias (part 2)
Sexual dysfunction
Problem that consistently impairs sexual arousal or functioning
Erectile disorder
Inability to develop or maintain an erection due to insufficient blood flow to the penis
Premature ejaculation
Sexual climax that occurs before the man or his partner wishes
Sexual Dysfunctions and Paraphilias (part 3)
Female orgasmic disorder
Distress due to infrequently or never experiencing orgasm
Paraphilias
Sexual arousal from fantasies, behaviors, or urges involving nonhuman objects, the suffering of self or others, and/or nonconsenting persons
Sexual Dysfunctions and Paraphilias (part 4)
American Psychological Association (2013)
Classifies people as disordered only if they experience sexual desire in unusual ways and:
The person experiences distress from unusual sexual interest or
The desire entails harm or risk of harm to others
Paraphilias include necrophilia, exhibitionism, and pedophilia.
Sexually Transmitted Infections (part 1)
Sexually transmitted infection (STI)
Also called sexually transmitted disease (STD)
Every day, more than 1 million people worldwide acquire an STI.
AIDS (acquired immune deficiency syndrome)
A life-threatening, sexually transmitted infection
Caused by the human immunodeficiency virus (HIV)
Depletes the immune system and leaves the person vulnerable to infections
Sexually Transmitted Infections (part 2)
CDC report: Sexually active 15- to 24-year-olds are at higher risk for STIs than older adults.
Condom use effectiveness varies by infection (80 percent effectiveness against transmission of HIV when used with infected partner; less effective with skin-to-skin STIs such as herpes).
Worldwide, women’s AIDS rates are increasing fastest, partly because the virus is passed from man to woman much more often than from woman to man.
Biopsychosocial Influences on Sexual Motivation
Compared with our motivation for eating, our sexual motivation is less influenced by biological factors. Psychological and social-cultural factors play a bigger role.
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The Psychology of Sex: External Stimuli
Research indicates exposure to sexually explicit material has adverse effects in three ways:
Believing rape is acceptable
Reducing satisfaction with a partner’s appearance or with a relationship
Desensitization
The Psychology of Sex: Imagined Stimuli
Imagined stimuli
Sexual desire and arousal can be imagined; the brain has been called the most significant sex organ.
People with spinal cord injury have reported feeling sexual desire.
Approximately 95 percent of people report having sexual fantasies.
Male fantasies tend to be more frequent, more physical, and less romantic than female fantasies.
Sexual Risk Taking and Teen Pregnancy
(part 1)
Environmental factors that influence a higher teen pregnancy rate:
Communication about birth control
Impulsivity
Alcohol use
Mass media: Norms of unprotected promiscuity; media help write the social scripts that affect our perceptions and actions
Sexual Risk Taking and Teen Pregnancy
(part 2)
Factors that predict sexual restraint:
High intelligence
Religious engagement
Father presence
Participation in service learning programs
Sexual Orientation
Sexual orientation is the enduring sexual attraction toward:
Members of one’s own sex (homosexual orientation)
The other sex (heterosexual orientation)
Both sexes (bisexual orientation)
In all cultures, heterosexuality has prevailed but homosexuality has existed. Where same-sex relationships are illegal, the prevalence of people who are lesbian, gay, or bisexual is no different.
Sexual Orientation: The Numbers
Survey results vary by survey methods and population; less open responses are found in less tolerant places.
Exclusively homosexual: 3 to 4 percent of men and 2 percent of women.
In the United States, 5 percent of men and 13 percent of women report some same-sex sexual contact during their lives.
APA (2009): Efforts to change sexual orientation are unlikely to be successful and involve some risk of harm.
Women’s sexual orientation tends to be less strongly felt and potentially more fluid; their sexual activity level also varies more.
Origins of Sexual Orientation (part 1)
Homosexuality is not linked to problems in parent–child relationships, does not involve a fear or hatred of the other sex, and is not significantly linked to childhood sexual victimization.
There is a lack of evidence for environmental causes of homosexuality.
Instead, homosexuality seems to have biological influences, as investigated in studies of same-sex behavior in other species, gay–straight brain differences, genetic influences, and prenatal influences.
Origins of Sexual Orientation (part 2)
Same-sex attraction in other species
Same-sex behavior has been observed in several hundred species—for example, swans, penguins, grizzlies, gorillas, monkeys, flamingos, and owls.
Gay–straight brain differences
One hypothalamic cell cluster is smaller in women and gay men than in straight men.
The anterior commissure is larger in gay men than in straight men.
Gay men’s hypothalamus reacts in the same way as straight women’s hypothalamus to the smell of sex-related hormones.
Origins of Sexual Orientation (part 3)
Genetic influences
Shared sexual orientation is higher among identical twins than among fraternal twins.
Sexual attraction in fruit flies can be genetically manipulated.
Male homosexuality often appears to be transmitted from the mother’s side of the family.
Origins of Sexual Orientation (part 4)
Prenatal influences
Altered prenatal hormone exposure may lead to homosexuality in humans and other animals.
Men with several older biological brothers are more likely to be gay, possibly due to a maternal immune-system reaction.
The consistency of the brain, genetic, and prenatal findings clearly leads to a biological explanation of sexual orientation.
The Older Brother Effect
Researcher Ray Blanchard (2008a) offers these approximate curves depicting a man’s likelihood of homosexuality as a function of his number of older brothers. This correlation has been found in several studies, but only among right-handed men (as about 9 in 10 men are).
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Gay–Straight Trait Differences
Research indicates that homosexuals and heterosexuals differ in the following traits:
Spatial abilities
Fingerprint ridge counts
Auditory system development
Handedness
Occupational preferences
Relative finger lengths Age of onset of puberty in males
Birth size and weight
Sleep length
Physical aggression
Walking style
Gender nonconformity
On average (the evidence is strongest for males), results for gays and lesbians fall between those of straight men and straight women. Three biological influences—brain, genetic, and prenatal—may contribute to these differences.
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Spatial Abilities and Sexual Orientation
Which of the three figures can be rotated to match the original figure? Straight males tend to find this type of mental rotation task easier than do straight females, with gays and lesbians falling in between.
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Male–Female Differences in Sexuality
Cross-culturally, men think more than women about sex, and men are more likely to think that casual sex is acceptable.
Why might natural selection have resulted in greater male promiscuity?
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Compared with lesbians, gay men (like straight men) report more interest in uncommitted sex, more responsiveness to visual sexual stimuli, and more concern with their partner’s physical attractiveness.
Gay male couples report having sex more often than do lesbian couples.
Men who have the trait of promiscuity are more likely to have their genes continue, and even spread, in the next generation. There is little cost to spreading their genes.
For women, a trait of promiscuity does not greatly increase the number of babies, and would have greater survival costs. Historically, pregnancy was often life-threatening.
An Evolutionary Explanation of Human Sexuality: Male–Female Differences in Sexuality
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Predict the Responses
Researchers asked samples of U.S. adults whether they agreed or disagreed with the following statements. For each item, give your best guess about the percentage who agreed with the statement.2
Statement Percentage of males
who agreed Percentage of females who agreed
If two people really like each other, it’s all right for them to have sex even if they’ve known each other for a very short time. —– —–
I can imagine myself being comfortable and enjoying “casual” sex with different partners. —– —–
Affection was the reason I first had intercourse. —– —–
I think about sex every day, or several times a day. —– —–
Pornography is “morally acceptable.” —– —–
Natural Selection and Mating Preferences
Men prefer women with signs of future fertility (narrow waist and fuller figure; age of peak fertility).
Women prefer men with loyal behavior and physical/social power and resources.
Why might natural selection have resulted in these mating preferences?
Male choices optimized the chance of producing offspring.
Female choices optimized offspring survival.
Men chose widely; women chose wisely!
Critiquing the Evolutionary Perspective
Most psychologists agree that natural selection prepares humans for survival and reproduction.
Critics of evolutionary psychology research note these limitations:
Evolutionary psychology starts with an effect and works backward to explain what happened.
More immediate explanations are better understood through social learning theory (including social scripts) than through decisions made by our distant ancestors.
Social consequences of evolutionary explanation are problematic.
Some traits and behaviors are difficult to explain by natural selection.
Sex and Human Relationships
Human sexuality research does not aim to define personal meaning of sex, but one significance of such intimacy is its expression of our profoundly social nature.
For both men and women, but especially for women, orgasm occurs more often when sex happens in a committed relationship rather than in a sexual hookup.
Sex is a socially significant act. Achieving orgasm alone is less satisfying, with much less of a surge in the prolactin hormone (associated with sexual satisfaction and satiety), than after sex with a loved one.
Thanks to overlapping brain reward areas, sexual desire and love feed each other.
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Reflections on the Nature and Nurture of Sex, Gender, and Sexuality
Our ancestral (genetic) history helped form humans as a species; where there is variation, natural selection, and heredity, there will be evolution.
Our culture and experiences also form us.
In many modern cultures, gender roles are merging.
Swift changes in gender roles and sexual attitudes have occurred since 1960.
Biology does not fix gender roles.
We cannot excuse our failings by blaming them solely on bad genes or bad influences. In reality, we are both the creatures and the creators of our worlds.
Sensation and Perception
Chapter 6
EXPLORING PSYCHOLOGY
DAVID G. MYERS | C. NATHAN DEWALL
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Chapter Overview
Basic Concepts of Sensation and Perception
Vision: Sensory and Perceptual Processing
The Nonvisual Senses
Processing Sensations and Perceptions
(part 1)
Sensation and perception are actually parts of one continuous process.
Sensation: The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
Perception: The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
Processing Sensations and Perceptions
(part 2)
Bottom-up processing: Sensory analysis that begins at the entry level, with information flowing from the sensory receptors to the brain
Top-down processing: Information processing guided by high-level mental processes, as when we construct perceptions by filtering information through our experience and expectations
Processing Sensations and Perceptions
(part 3)
All our senses:
Receive sensory stimulation, often using specialized receptor cells
Transform that stimulation into neural impulses
Deliver the neural information to our brain
Transduction
Conversion of one form of energy into another
In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret
Processing Sensations and Perceptions
(part 4)
Absolute threshold
The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time
Tested by defining the point where half the time a stimulus is detected and half the time it is not
Gustav Fechner (1801–1887), a German scientist and philosopher, studied our awareness of these faint stimuli.
Processing Sensations and Perceptions
(part 5)
Signal detection theory
Predicts how and when we will detect a faint stimulus (signal) amid background stimulation (noise)
Individual thresholds vary depending on the strength of the signal and on our experience, expectations, motivation, and alertness.
Absolute Threshold (part 1)
Absolute threshold: Minimum stimulation needed to detect a particular stimulus 50% of the time
Can see a far away light in the dark, feel the slightest touch
Subliminal: Input below the absolute threshold for conscious awareness
Priming: Activating, often unconsciously, associations in our mind, thereby setting us up to perceive, remember, or respond to objects or events in certain ways
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Absolute Threshold (part 2)
Can I detect this sound? An absolute threshold is the intensity at which a person can detect a stimulus half the time. Hearing tests locate these thresholds for various frequencies.
9
Processing Sensations and Perceptions (part 6)
Difference threshold: Minimum difference that a person can detect between any two stimuli half the time
Increases with stimulus size
A 5-decibel increase in volume will be noticed at a starting point of 40 decibels, but not at 110 decibels
Experienced as a just noticeable difference (JND)
Weber’s law: For an average person to perceive a difference, two stimuli must differ by a constant minimum percentage (not a constant amount).
The exact proportion varies, depending on the stimulus.
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Subliminal Persuasion
Subliminal stimuli are those that are too weak to detect 50 percent of the time; they are below the absolute threshold.
Subliminal sensation exists, but such sensations are too fleeting to enable exploitation with subliminal messages.
Subliminal persuasion may produce a fleeting and subtle but not powerful or enduring effect on behavior (Greenwald, 1992).
Experiments disprove claims of the effectiveness of subliminal advertising and self-improvement.
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Sensory Adaptation
Sensory adaptation
Is diminished sensitivity as a consequence of constant stimulation
Aids focus by reducing background chatter
Influences how the world is perceived in a personally useful way
Our sensory receptors are sensitive to novelty; sensory adaptation even influences how we perceive emotions.
We perceive the world not exactly as it is, but as it is useful for us to perceive it.
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Emotion Adaptation
Gaze at the angry face on the left for 20 to 30 seconds, then look at the center face (looks scared, yes?). Then gaze at the scared face on the right for 20 to 30 seconds, before returning to the center face (now looks angry, yes?). (From Butler et al., 2008.)
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Perceptual Set
Perceptual set: Mental tendencies and assumptions that affect (top-down) what we hear, taste, feel, and see.
What determines our perceptual set?
Schemas organize and interpret unfamiliar information through experience.
Preexisting schemas influence top-down processing of ambiguous sensation interpretation, including gender stereotypes.
Perceptions are influenced, top-down, not only by our expectations and by the context, but also by our emotions and motivation.
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Context Effects
A given stimulus may trigger different perceptions because of the immediate context.
CULTURE AND CONTEXT EFFECTS
What is above the woman’s head? In one classic study, nearly all the East Africans who were questioned said the woman was balancing a metal box or can on her head and that the family was sitting under a tree. What do you think Westerners said?
A given stimulus may trigger different perceptions, partly because of a differing perceptual set, but also because of the immediate context. Westerners, for whom corners and boxlike architecture were more common, were more likely to perceive the family as being indoors, with the woman sitting under a window. (Gregory & Gombrich, 1973.)
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Motivation and Emotion
Perceptions are also influenced by our motivation and emotions.
Walking destinations look farther away when we are fatigued.
Slopes look steeper when we are wearing a heavy backpack (or after listening to sad, heavy classical music).
Water bottles look closer when we are thirsty.
Emotions and motives also influence our social perceptions.
Light Energy and Eye Structures
Wavelength: Distance from the peak of one light wave or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission.
Intensity: Amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height).
Hue: Dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
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The Stimulus: Light Energy
What is seen as light is only a thin slice of the broad spectrum of electromagnetic energy.
The portion visible to humans extends from the shorter waves of blue-violet light to the longer waves of red light.
Other organisms are sensitive to differing portions of the spectrum; bees, for instance, cannot see what we perceive as red but can see ultraviolet light.
The perceived hue in a light depends on its wavelength, and its brightness depends on its intensity.
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The Wavelengths We See
What we see as light is only a tiny slice of a wide spectrum of electromagnetic energy, which ranges from gamma rays as short as the diameter of an atom to radio waves over a mile long. The wavelengths visible to the human eye extend from the shorter waves of blue-violet light to the longer waves of red light.
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The Physical Properties of Light Waves
Waves vary in wavelength, the distance between successive peaks. Frequency, the number of complete wavelengths that can pass a point in a given time, depends on the length of the wave. Wavelength determines the perceived color of light.
Waves also vary in amplitude, the height from peak to trough (top to bottom). This wave amplitude influences the brightness of colors (light waves), as well as the loudness of sounds (sound waves).
The shorter the wavelength, the higher the frequency. Wavelength determines the perceived color of light and the pitch of sound.
Physical energy seen as light:
Wavelength: Distance from one wave peak to the next.
Hue: Color experienced.
Amplitude: Height.
Intensity: Amount of contained energy; influences brightness.
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Light Energy and Eye Structures (part 1)
The eye
Cornea: Portion of the eye through which light passes (to the pupil and lens) and is bent to help provide focus
Pupil: A small adjustable opening through which the light then passes
Iris: A colored muscle surrounding the pupil that controls its size
Lens: Focuses incoming light rays onto an image on the retina on the eyeball’s sensitive inner surface
After entering the eye and being focused by a lens, light energy particles strike the eye’s inner surface, the retina.
Light Energy and Eye Structures (part 2)
The retina
Contains two types of receptors: rods and cones
Has layers of neurons that begin the processing of visual information
Accommodation
The process by which the eye’s lens changes shape to focus near or far objects on the retina
The Eye
Light rays reflected from a candle pass through the cornea, pupil, and lens.
The curve and thickness of the lens change to bring nearby or distant objects into focus on the retina.
Rays from the top of the candle strike the bottom of the retina. Those from the left side of the candle strike the right side of the retina.
The candle’s image appears on the retina upside down and reversed.
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The Eye-to-Brain Pathway
Light-energy particles trigger chemical reactions in receptor cells, rods and cones, that form an outer layer of cells of the retina at the back of the eye.
Rods: Retinal receptors that detect black, white, and gray; sensitive to movement; necessary for peripheral and twilight vision (when cones don’t respond)
Cones: Receptors concentrated near the center of the retina; function in daylight or well-lit conditions; detect fine detail and color
The Retina’s Reaction to Light
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Rods and Cones
Cones are sensitive to detail and color.
Rods are sensitive to faint light.
Cones Rods
Number 6 million 120 million
Location in retina Center Periphery
Sensitivity in dim light Low High
Color sensitivity High Low
Detail sensitivity High Low
Rods detect black, white, and gray, and are necessary for peripheral and twilight vision.
Cones are clustered near the center of the retina; they detect fine detail and allow color vision.
Light energy triggers chemical changes in the rods and cones, which activate the bipolar cells.
These cells then activate the ganglion cells of the optic nerve, which transmits the neural impulses from the eye to the brain.
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Information Processing in the Eye and Brain
Retinal processing
Optic nerve: Carries neural impulses from the eye to the brain
Blind spot: The point at which the optic nerve leaves the eye, where no receptor cells are located
Fovea: The central focal point in the retina, around which the eye’s cones cluster
Pathway From the Eyes to the Visual Cortex
Ganglion axons forming the optic nerve run to the thalamus, where they synapse with neurons that run to the visual cortex.
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Color Processing
Color processing is a two-stage process:
Young-Helmholtz trichromatic theory: The retina’s red, green, and blue cones respond in varying degrees to different color stimuli.
Hering’s opponent-process theory: Cones’ responses are then processed by opponent-process cells.
Feature Detection
Feature detectors: Specialized nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
These cells receive information from the ganglion cells in the retina.
They pass the information to other cortical areas, where teams of cells (supercell clusters) respond to more complex patterns.
Face Recognition Processing
In social animals such as humans, a large right temporal lobe area (shown here in a right-facing brain) is dedicated to the crucial task of face recognition.
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Parallel Processing (part 1)
Parallel processing: The brain’s ability to do many things at once
A visual scene is first divided into subdimensions.
Perceptions are constructed by integrating separate but parallel subdimensions.
Parallel Processing (part 2)
Studies of patients with brain damage suggest that the brain delegates the work of processing motion, form, depth, and color to different areas. After taking a scene apart, the brain integrates these subdimensions into the perceived image.
The brain divides the work of processing into subdimensions—motion, form, depth, color—and works on each aspect simultaneously (Livingstone & Hubel, 1988).
How does the brain do this? The answer to this question is the Holy Grail of vision research.
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Perceptual Organization
Gestalt: An organized whole
Gestalt psychologists propose principles used to organize sensations into meaningful wholes.
In perception, the whole may exceed the sum of its parts.
We filter incoming information and construct perceptions.
Form Perception (part 1)
How do we organize and interpret the shapes and colors into meaningful perceptions?
People tend to organize pieces of information into an organized whole, or gestalt.
A Necker cube
What do you see: circles with white lines, or a cube?
If you stare at the cube, you may notice that it reverses location, moving the tiny X in the center from the front edge to the back.
At times the cube may seem to float forward, with circles behind it.
At other times, the circles may become holes through which the cube appears, as though it were floating behind them.
There is far more to perception than meets the eye. (From Bradley et al., 1976.)
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Form Perception (part 2)
Figure-ground: The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)
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Form Perception (part 3)
Grouping: The perceptual tendency to organize stimuli into coherent groups
Proximity: Grouping nearby figures together
Continuity: Perceiving smooth, continuous patterns, rather than discontinuous ones
Closure: Filling in gaps to create a complete, whole object
Grouping
Human minds use these grouping strategies to see patterns and objects.
Proximity: We group nearby figures together. We see not six separate lines, but three sets of two lines.
Continuity: We perceive smooth, continuous patterns rather than discontinuous ones. This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines—one wavy, one straight.
Closure: We fill in gaps to create a complete, whole object. Thus, we assume that the circles on the left are complete but partially blocked by the (illusory) triangle. Adding nothing more than little line segments to close off the circles prompts your brain to construct a triangle.
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Depth Perception
Depth perception: The ability to see objects in three dimensions, although the images that strike the retina are two-dimensional
Allows us to judge distance
Is present, at least in part, at birth in humans and other animals
The Visual Cliff
Test of early 3-D perception
Most infants refuse to crawl across the visual cliff
Crawling, no matter when it begins, seems to increase an infant’s fear of heights
Depth cue: Pattern on floor
Visual cliff: Eleanor Gibson and Richard Walk devised this miniature cliff with a glass-covered drop-off to determine whether crawling infants and newborn animals can perceive depth. Even when coaxed, infants are reluctant to venture onto the glass over the cliff.
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Depth Perception (part 1)
Binocular cues
Two eyes help with perception of depth
Retinal disparity
Binocular cue for perceiving depth
By comparing images from the retinas in the two eyes, the brain calculates distance
Used by 3-D film makers
Retinal disparity: Binocular cue for perceiving depth.
By comparing images from the two eyes, the brain computes distance.
The greater the disparity (difference) between the two images, the closer the object.
Retinal disparity can differentiate between 1 and 10 feet away, but not between 10 and 100 feet.
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Depth Perception (part 2)
Monocular cues
Depth cue, such as interposition or linear perspective, available to either eye alone
Relative height
Relative size
Interposition
Linear perspective
Light and shadow
Relative motion
Motion perception
Stroboscopic movement
Phi phenomenon
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Perceptual Constancy (part 1)
Perceptual constancy: Objects are perceived as unchanging (having consistent color, brightness, shape, and size), even as illumination and retinal images change.
Perceptual Constancy (part 2)
Color and brightness constancies
Color constancy: Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the objects
Brightness constancy: Similarly depends on context
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Shape and Size Constancies
Shape constancy: Perceiving the form of familiar objects as constant even when our retinas receive changing images of them
Size constancy: Perceiving objects as having constant size even when distance from them varies
An opening door looks more and more like a trapezoid, yet we still perceive it as a rectangle.
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Experience and Visual Perception
Restored vision and sensory restriction
The effects of sensory restriction on infant cats, monkeys, and humans suggest there is a critical period for normal sensory and perceptual development.
Without stimulation, normal connections do not develop.
Perceptual adaptation
Ability to adjust to an artificially displaced or even inverted visual field
Early nurture sculpts what nature has endowed.
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The Nonvisual Senses: Hearing
Sound waves: From the environment into the brain
Sound waves compress and expand air molecules
Ears detect these brief pressure changes
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The Sounds of Music
A violin’s short, fast waves create a high pitch; the longer, slower waves of a cello or bass create a lower pitch.
Differences in the waves’ height, or amplitude, also create differing degrees of loudness.
The Stimulus Input: Sound Waves (part 1)
Audition: The sense or act of hearing
Amplitude (height) determines intensity (loudness) in sound waves
Length (frequency) determines the pitch
Frequency: The number of complete wavelengths that pass a point in a given time (for example, per second)
Pitch: A tone’s experienced highness or lowness; depends on frequency
Sound is measured in decibels (dB)
Low frequency = long wavelength = low pitch
Decibels
0 dB: The absolute threshold (not the absence of sound, just less than humans can hear)
60 dB: Normal conversation
85+ dB: Prolonged exposure can cause hearing loss
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The Physical Properties of Sound Waves
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The Stimulus Input: Sound Waves (part 2)
Sound waves are bands of compressed and expanded air.
Human ears detect these changes in air pressure and transform them into neural impulses, which the brain decodes as sound.
Sound waves vary in amplitude, which is perceived as differing loudness, and in frequency, which is experienced as differing pitch.
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The Ear
Vibrating air (sound waves) enter the outer ear and pass through the auditory canal to the eardrum.
Middle ear: Chamber between the eardrum and cochlea; contains three tiny bones that amplify the vibrations of the eardrum
Cochlea: A coiled, bony, fluid-filled tube in the inner ear; contains nerve receptors
Inner ear: Innermost part of the ear; contains the cochlea, semicircular canals, and vestibular sacs
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Decoding Sound Waves
Sound waves strike the eardrum, causing it to vibrate.
Tiny bones in the middle ear pick up the vibrations and transmit them to the cochlea, a coiled, fluid-filled tube in the inner ear.
Ripples in the fluid of the cochlea bend the hair cells lining the surface, which trigger impulses in nerve cells.
Axons from these nerve cells transmit a signal to the auditory cortex.
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Transforming Sound Energy Into Neural Messages
Hear here: How we transform sound waves into nerve impulses that our brain interprets. (a) The outer ear funnels sound waves to the eardrum. The bones of the middle ear (hammer, anvil, and stirrup) amplify and relay the eardrum’s vibrations through the oval window into the fluid-filled cochlea. (b) As shown in this detail of the middle and inner ear, the resulting pressure changes in the cochlear fluid cause the basilar membrane to ripple, bending the hair cells on its surface. Hair cell movements trigger impulses at the base of the nerve cells, whose fibers converge to form the auditory nerve. That nerve sends neural messages to the thalamus and on to the auditory cortex.
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The Ear
Sensorineural hearing loss (nerve deafness)
Damage to cell receptors or associated nerves
Conduction hearing loss
Damage to the mechanical system that conducts sound waves to the cochlea
Cochlear implant: A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.
A neural response is triggered when the tiny bundles of cilia on top of even one of the 16,000 hair cells on the cochlea are moved even the width of an atom!
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Perceiving Loudness, Pitch, and Location
(part 1)
Responding to loud and soft sounds
The brain interprets loudness base on the number of activated receptors.
Soft tones activate fewer hair cells.
People who lose all hearing in one ear often have difficulty locating sounds.
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Perceiving Loudness, Pitch, and Location
(part 2)
Hearing different pitches
Place theory in hearing: Theory that links the pitch heard with the place where the cochlea’s membrane is stimulated; best explains high pitches
Frequency theory (temporal theory) in hearing: Theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling its pitch to be sensed; explains low pitches
Some combination of the place and frequency theories seems to explain the pitches in the intermediate range.
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How We Locate Sounds
Sound waves strike one ear sooner and more intensely than the other.
From this information, our brain can compute the sound’s location.
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The Other Senses: Touch
Sense of touch is actually a mix of four distinct skin senses:
Pressure
Warmth
Cold
Pain
Other skin sensations are variations of these basic four.
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Pain
Women are more sensitive to pain than men.
Pain sensitivity depends on genes, physiology, experience, attention, and surrounding culture.
Gate-control theory: The spinal cord contains a neurological “gate” that either blocks pain signals or allows them to pass on to the brain.
The “gate” is opened by the activity of pain signals traveling up nerve fibers; it is closed by activity in larger fibers or by information coming from the brain.
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Biopsychosocial Approach to Pain
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The Pain Circuit
Sensory receptors (nociceptors) respond to potentially damaging stimuli by sending an impulse to the spinal cord, which passes the message to the brain, which interprets the signal as pain.
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Controlling Pain
Placebo: Reduces CNS attention and responses to pain
Distraction: Draws attention away from painful stimulation
fMRI scans reveal virtual reality play reduces the brain’s pain-related activity.
Hypnosis
Social influence theory
Dissociation: Dual processing; sensory information does not reach areas where pain-related information is processed
Selective attention
Posthypnotic suggestion
The Other Senses: Taste
Like touch, taste:
Involves several basic sensations
Can be influenced by learning, expectations, and perceptual bias
Has a survival function
Taste Indicates
Sweet Energy source
Salty Sodium essential to physiological processes
Sour Potentially toxic acid
Bitter Potential poisons
Umami Proteins to grow and repair tissue
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Sensory interaction: One sense may influence another
Smell + texture + taste = flavor
Taste
Inside each little bump on the top and sides of the tongue are more than 200 taste buds.
Each bud contains a pore with 50–100 taste receptors.
Each kind of receptor reacts to different types of food molecules and sends messages to the brain.
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The Other Senses: Smell
Olfaction: Experience of smell
Like taste, smell is a chemical sense.
Olfactory receptor cells are located in the olfactory bulb in the nose.
A combination of several odor molecules stimulate different receptors to detect them.
These patterns are interpreted by the olfactory cortex.
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The Sense of Smell
If you are to smell a flower, airborne molecules of its fragrance must reach receptors at the top of your nose. Sniffing swirls air up to the receptors, enhancing the aroma. The receptor cells send messages to the brain’s olfactory bulb, and then onward to the temporal lobe’s primary smell cortex and to the parts of the limbic system involved in memory and emotion.
Information from the taste buds travels to an area between the frontal and temporal lobes of the brain.
It registers in an area not far from where the brain receives information from our sense of smell, which interacts with taste.
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Smell (part 1)
The nose knows
Humans have some 20 million olfactory receptors.
A bloodhound has 220 million (Herz, 2007).
Different combinations of receptors identify different smells.
Our brain’s circuitry helps explain an odor’s power to evoke feelings, memories, and behaviors.
A hotline runs between the brain area that receives information from the nose and brain centers associated with emotions and memories.
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Smell (part 2)
Information from the taste buds travels to an area between the frontal and temporal lobes of the brain. It registers in an area not far from where the brain receives information from our sense of smell, which interacts with taste.
The brain’s circuitry for smell also connects with areas involved in memory storage, which helps explain why a smell can trigger a memory.
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The Other Senses: Body Position and Movement
Kinesthesia: System for sensing the position and movement of individual body parts
Interacts with vision
Vestibular sense: Sense of body movement and position, including the sense of balance
Sensory Interaction (part 1)
Senses are not totally separate information channels.
Sensory interaction: The principle that one sense may influence another, as when the smell of food influences taste.
Smell + texture + taste = flavor
Vision + hearing interact
Taste, Smell, and Memory
Information from the taste buds (yellow arrow) travels to an area between the frontal and temporal lobes of the brain. It registers in an area not far from where the brain receives information from our sense of smell, which interacts with taste. The brain’s circuitry for smell (red area) also connects with areas involved in memory storage, which helps explain why a smell can trigger a memory.
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Sensory Interaction (part 2)
Embodied cognition: Influence of bodily sensations, gestures, and other states on cognitive preferences and judgments
Physical warmth may promote social warmth.
Social exclusion can literally feel cold.
Political expressions may mimic body positions.
ESP: Perception Without Sensation?
Most relevant ESP claims
Telepathy, clairvoyance, precognition
ESP is studied by parapsychologists
What do YOU think?
Bem
Nine experiments seemed to suggest participants could anticipate future events
Critics
Methods or analysis viewed as flawed
Most research psychologists and scientists are skeptical
Extrasensory perception (ESP): The controversial claim that perception can occur apart from sensory input, such as through telepathy, clairvoyance, and precognition.
Telepathy: Mind-to-mind communication.
Clairvoyance: Perceiving remote events, such as a house on fire in another state.
Precognition: Perceiving future events, such as an unexpected death in the next month.
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Learning
Chapter 7
EXPLORING PSYCHOLOGY
DAVID G. MYERS | C. NATHAN DEWALL
Chapter Overview
Basic Learning Concepts and Classical Conditioning
Operant Conditioning
Biology, Cognition, and Learning
How Do We Learn? (part 1)
Learning: Process of acquiring through experience new and relatively enduring information or behaviors
Associative learning: Learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning).
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How Do We Learn? (part 2)
Stimulus: An event or situation that evokes a response.
Conditioning: The process of learning associations, which takes two main forms:
Classical conditioning: We associate stimuli that we do not control, and we automatically respond (exhibiting respondent behaviors).
Operant conditioning: We associate a response (our behavior) and its consequence (producing operant behaviors).
Cognitive learning: The acquisition of mental information, whether by observing events, by watching others, or through language.
Observational learning: A form of cognitive learning that lets us learn from others’ experiences.
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Classical Conditioning (part 1)
Ivan Pavlov’s early twentieth-century experiments are psychology’s most famous research.
Classical conditioning: Type of learning in which one learns to link two or more stimuli and anticipate events.
Behaviorism:
Psychology (1) should be an objective science that (2) studies behavior without reference to mental processes.
Most research psychologists today agree with (1) but not with (2).
Classical Conditioning (part 2)
Pavlov studied the digestive system; he was the recipient of Russia’s first Nobel Prize (1904). An incidental observation triggered his new research direction.
Pavlov’s Device for Recording Salivation
A tube in the dog’s cheek collects saliva, which is measured in a cylinder outside the chamber.
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Classical Conditioning (part 3)
Neutral stimulus (NS): In classical conditioning, a stimulus that elicits no response before conditioning.
Unconditioned response (UR): In classical conditioning, an unlearned, naturally occurring response (such as salivation) to an unconditioned stimulus (such as food in the mouth).
Unconditioned stimulus (US): In classical conditioning, a stimulus that unconditionally—naturally and automatically—triggers an unconditioned response.
Classical Conditioning (part 4)
Conditioned response (CR): In classical conditioning, a learned response to a previously neutral (but now conditioned) stimulus.
Conditioned stimulus (CS): In classical conditioning, an originally irrelevant stimulus, that, after association with an unconditioned stimulus, comes to trigger a conditioned response.
For three decades, Pavlov’s research demonstrated associative learning, exploring five major conditioning processes: acquisition, extinction, spontaneous recovery, generalization, and discrimination.
Classical Conditioning (part 5)
Acquisition
Initial stage
When one links a neutral stimulus and an unconditioned stimulus so that the neutral stimulus begins triggering the conditioned response
Extinction
Diminishing of a conditioned response
Occurs in classical conditioning when an unconditioned stimulus does not follow a conditioned stimulus
Spontaneous recovery
Reappearance, after a pause, of an extinguished conditioned response
Idealized Curve of Acquisition, Extinction, and Spontaneous Recovery
The rising curve shows the CR rapidly growing stronger as the NS becomes a CS due to repeated pairing with the US (acquisition). The CR then weakens rapidly as the CS is presented alone (extinction). After a pause, the (weakened) CR reappears (spontaneous recovery).
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Classical Conditioning (part 6)
Generalization
Tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses
Discrimination
Learned ability to distinguish between a conditioned stimulus (which predicts the unconditioned stimulus) and other irrelevant stimuli
Generalization
Pavlov demonstrated generalization by attaching miniature vibrators to various parts of a dog’s body.
After conditioning salivation to stimulation of the thigh, Pavlov stimulated other areas of the dog’s body.
The closer a stimulated spot to the dog’s thigh, the stronger the conditioned response. (From Pavlov, 1927.)
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Pavlov’s Legacy
The consensus among psychologists is that classical conditioning is a basic form of learning.
Why should we care that dogs can be conditioned to the sound of a tone? Many other responses to many other stimuli can be classically conditioned in many other organisms.
Pavlov demonstrated how a learning process can be studied objectively.
Classical conditioning is a basic form of learning that applies to all species.
Applications of Classical Conditioning
(part 1)
Pavlov’s principles are used to influence human health and well-being:
Areas of consciousness
Motivation
Emotion
Health
Psychological disorders
Therapy
Addicts are counseled to avoid stimuli (for example, people and settings) that may trigger cravings.
Pairing a particular taste with a drug that influences immune responses may eventually lead to immune response from the taste alone.
Applications of Classical Conditioning
(part 2)
Pavlov’s work provided a basis for Watson’s ideas that human emotions and behaviors, though biologically influenced, are mainly a bundle of conditioned responses.
Watson applied classical conditioning principles in his studies of “Little Albert” to demonstrate how specific fears might be conditioned.
Watson boasted that he could take any healthy infant and train the child for any career specialization, regardless of any inborn traits, but later admitted to “going beyond his facts.”
Operant Conditioning (part 1)
Operant conditioning: A type of learning in which behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher.
Operant behavior: Behavior that operates on the environment to produce rewarding or punishing stimuli.
In contrast, classical conditioning involves respondent behavior—automatic responses to a stimulus.
Operant Conditioning (part 2)
Behavior operates on the environment to produce rewarding or punishing stimuli.
Organisms associate their own actions with consequences.
Actions followed by reinforcement increase; those followed by punishments often decrease.
Skinner’s Experiments (part 1)
B. F. Skinner (1904–1990): Modern behaviorism’s most influential and controversial figure
Expanded on Edward L. Thorndike’s law of effect, which states that rewarded behavior tends to recur
Developed behavioral technology that revealed principles of behavior control
Designed and used an operant chamber (Skinner box) for experiments that included a bar (a lever) that an animal presses (or a key or disc that the animal pecks) to release a reward of food or water, as well as a device that records these responses.
Skinner’s Experiments (part 2)
Cat in a Puzzle Box
Thorndike used a fish reward to entice cats to find their way out of a puzzle box through a series of maneuvers. The cats’ performance tended to improve with successive trials, illustrating Thorndike’s law of effect.
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Skinner’s Experiments (part 3)
By shaping animals’ natural behaviors, Skinner was able to teach these animals unnatural behaviors (such as teaching pigeons to walk in a figure 8, play Ping-Pong, and keep a missile on course by pecking at a screen target).
Reinforcement: Any event that strengthens the behavior it follows.
A Skinner box
Inside the box, the rat presses a bar for a food reward. Outside, a measuring device (not shown) records the animal’s accumulated responses.
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Shaping Behavior
Everyday behaviors are continually reinforced and shaped.
Shaping: Gradually guiding behavior toward closer and closer approximations of the desired behavior.
With the method of successive approximations, responses that are increasingly closer to the final desired behavior are rewarded; all other responses are ignored.
Operant Conditioning: Types of Reinforcers
Positive reinforcement: Increases behaviors by presenting positive reinforcers.
A positive reinforcer is any stimulus that, when presented after a response, strengthens the response.
Negative reinforcement: Increases behaviors by stopping or reducing negative stimuli.
A negative reinforce is any stimulus that, when removed after a response, strengthens the response. (Note that it is not punishment.)
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Ways to Increase Behavior
Operant Conditioning Term Description Examples
Positive reinforcement Add a desirable stimulus Pet a dog that comes when you call it; pay someone for work done.
Negative reinforcement Remove an aversive stimulus Take painkillers to end pain; fasten seatbelt to end loud beeping.
Negative reinforcement is not punishment.
The point to remember: Whether it works by reducing something aversive or by providing something desirable, reinforcement is any consequence that strengthens behavior.
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Operant Conditioning: Types of Reinforcers
Primary and conditioned reinforcers
Primary reinforcer: An unlearned, innately reinforcing stimulus, such as one that satisfies biological needs
Conditioned (secondary): A stimulus that gains power through association with primary reinforcer
Immediate and delayed reinforcers
Immediate: Occurs immediately after a behavior
Delayed: Involves a time delay between the desired response and delivery of the reward
Reinforcement Schedules (part 1)
Reinforcement schedule: A pattern that defines how often a desired response will be reinforced
Continuous reinforcement schedule: Reinforcing the desired response every time it occurs
Partial (intermittent) reinforcement schedule: Reinforcing a response only part of the time; results in slower acquisition of a response but much greater resistance to extinction than does continuous reinforcement
Reinforcement Schedules (part 2)
Fixed-ratio schedule: Reinforcing a response only after a specified number of responses
Variable-ratio schedule: Reinforcing a response after an unpredictable number of responses
Fixed-interval schedule: Reinforcing a response only after a specified time has elapsed
Variable-interval schedule: Reinforcing a response at unpredictable time intervals
Intermittent Reinforcement Schedules
Skinner’s (1961) laboratory pigeons produced four reinforcement schedules. (Reinforcers are indicated by diagonal marks.)
For people, as for pigeons, reinforcement linked to number of responses (a ratio schedule) produces a higher response rate than reinforcement linked to amount of time elapsed (an interval schedule).
The predictability of the reward also matters. An unpredictable (variable) schedule produces more consistent responding than does a predictable (fixed) schedule.
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Reinforcement Schedules (part 3)
Fixed Variable
Ratio Every so many: reinforcement after every nth behavior, such as buy 10 coffees, get 1 free, or pay workers per product unit produced After an unpredictable number: reinforcement after a random number
of behaviors, as when playing slot machines or fly fishing
Interval Every so often: reinforcement for
behavior after a fixed time, such as Tuesday discount prices Unpredictably often: reinforcement for
behavior after a random amount of time, as when checking our phone for
a message
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Punishment (part 1)
Punishment administers an undesirable consequence or withdraws something desirable in an attempt to decrease the frequency of a behavior (e.g., a child’s disobedience).
Positive punishment: Presenting a negative consequence after an undesired behavior is exhibited, making that behavior less likely to happen in the future.
Negative punishment: Removing a desired stimulus after a particular undesired behavior is exhibited, resulting in reducing that behavior in the future.
Punishment (part 2)
Fixed Variable
Ratio Every so many: reinforcement after every nth behavior, such as buy 10 coffees, get 1 free, or pay workers per product unit produced After an unpredictable number: reinforcement after a random number
of behaviors, as when playing slot machines or fly fishing
Interval Every so often: reinforcement for
behavior after a fixed time, such as Tuesday discount prices Unpredictably often: reinforcement for
behavior after a random amount of time, as when checking our phone for
a message
Table 7.3
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Four Major Drawbacks of Physical Punishment
The punished behavior is suppressed, but not forgotten. This temporary state may (negatively) reinforce parents’ punishing behavior.
Punishment teaches discrimination among situations—perhaps only selectively decreasing the undesired behavior.
Punishment can teach fear.
Physical punishment may increase aggression by modeling violence as a way to cope with problems.
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Applications of Operant Conditioning
At school: Electronic technologies and adaptive learning software used in teaching and learning have helped realize Skinner’s goal of individually paced, customized instruction with immediate feedback.
In sports: Behavioral methods are used to shape behavior in athletic performance.
At work: Rewards have been successfully used to increase productivity and skill development.
At home: Basic rules of shaping are used in parenting, and to reinforce our own desired behaviors.
Reinforcing Desired Behaviors and Extinguishing Undesired Behaviors
State a realistic goal in measurable terms.
Decide how, when, and where you will work toward your goal.
Monitor how often you engage in your desired behavior.
Reinforce the desired behavior.
Reduce the rewards gradually.
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Contrasting Classical and Operant Conditioning
Classical Conditioning Operant Conditioning
Basic idea Learning associations between events we do not control. Learning associations between our behavior and its consequences.
Response Involuntary, automatic. Voluntary, operates on environment.
Acquisition Associating events; NS is paired with US and becomes CS. Associating a response with a consequence (reinforcer or punisher).
Extinction CR decreases when CS is repeatedly presented alone. Responding decreases when reinforcement stops.
Spontaneous recovery The reappearance, after a rest period, of an extinguished CR. The reappearance, after a rest period, of an extinguished response.
Generalization The tendency to respond to stimuli similar to the CS. Responses learned in one situation occurring in other, similar situations.
Discrimination Learning to distinguish between a CS and other stimuli that do not signal a US. Learning that some responses, but not others, will be reinforced.
Both classical and operant conditioning are forms of associative learning.
Both involve acquisition, extinction, spontaneous recovery, generalization, and discrimination.
Classical conditional involves respondent behaviors; operant conditioning involves operant behaviors.
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Biology, Cognition, and Learning
Biopsychosocial influences on learning: Our learning results not only from environmental experiences, but also from cognitive and biological influences.
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Biological Limits on Classical Conditioning
(part 1)
Biological constraints: Evolved biological tendencies that predispose animals’ behavior and learning, making certain behaviors easier to learn than others.
Example: Garcia and Koelling’s taste-aversion research
Animals, including humans, seem biologically prepared to learn some associations rather than others.
Conditioning is stronger when the CS is ecologically relevant.
The genetic predisposition to associate a CS with an US that follows predictably and immediately is adaptive.
Biological Limits on Classical Conditioning
(part 2)
Nature limits species’ capacity for operant conditioning.
Biological constraints predispose organisms to learn associations that are naturally adaptive.
Instinctive drift occurs as animals revert to biologically predisposed patterns.
Cognition and Classical Conditioning
(part 1)
Mental information that guides behavior is acquired through cognitive learning.
Animals learn the predictability of an event (Rescorla & Wagner, 1972).
The more predictable the association between a neutral stimulus and an unconditioned stimulus, the stronger the conditioned response.
It’s as if the animal learns an expectancy—an awareness of how likely it is that the US will occur.
Cognition and Classical Conditioning
(part 2)
Skinner acknowledged the biological underpinnings of behavior but has been criticized for discounting the importance of cognition.
Evidence of cognitive processes
Animal response on a fixed-interval reinforcement schedule
Development of cognitive maps in rats (latent learning that becomes evident only when there is an incentive to demonstrate it)
Intrinsic motivation: A desire to perform a behavior effectively for its own sake
Extrinsic motivation: A desire to perform a behavior to receive promised rewards or avoid threatened punishment
Cognition and Classical Conditioning
(part 3)
Classical Conditioning Operant Conditioning
Biological influences Natural predispositions constrain what stimuli and responses can easily be associated. Organisms most easily learn behaviors similar to their natural behaviors; unnatural behaviors instinctively drift back toward natural ones.
Cognitive influences Organisms develop an expectation that a CS signals the arrival of a US.
Organisms develop an expectation that a response will be reinforced or punished; they also exhibit latent learning, without reinforcement.
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Learning by Observation
Observational learning: Higher animals, especially humans, learn without direct experience by watching and imitating others.
Albert Bandura is the pioneering researcher of observational learning
His Bobo doll experiment showed direct imitation by children of adult behavior.
Modeling: The process of observing and imitating a specific behavior.
Vicarious reinforcement and vicarious punishment are experienced by watching models.
The Bobo Doll Experiment
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Mirrors and Imitation in the Brain
Mirror neurons: Frontal lobe neurons that some scientists believe fire when a person performs certain actions or observes another doing so; provide a neural basis for everyday imitation and observational learning.
The brain’s mirroring of another’s action may enable imitation and empathy.
In humans, imitation is pervasive: So strong is the human predisposition to learn from watching adults that children will overimitate, copying even irrelevant adult actions.
The brain response to observing others makes emotions contagious.
Experienced and Imagined Pain in the Brain
Brain activity related to actual pain (left) is mirrored in the brain of an observing loved one (right). Empathy in the brain shows up in emotional brain areas, but not in the somatosensory cortex, which receives the physical pain input.
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Applications of Observational Learning
(part 1)
Prosocial effects
Prosocial modeling of behavior can have prosocial effects.
Behavior modeling enhances learning of communication, sales, and customer service skills in new employees.
Modeling nonviolent, helpful behavior prompts similar behavior in others.
Research across seven countries showed that viewing prosocial media increased later helping behavior.
Socially responsive toddlers tend to have a strong internalized conscience as preschoolers.
Models are most effective when they include consistent actions and words.
Applications of Observational Learning
(part 2)
Antisocial effects
Abusive parents may have aggressive children.
Watching TV and videos may teach children:
Bullying is an effective tool for controlling others.
Free and easy sex doesn’t have later consequences.
Men should be tough; women should be gentle.
The violence-viewing effect is demonstrated when viewing media violence triggers violent behavior.
Watching cruelty may foster indifference.
Memory
Chapter 8
EXPLORING PSYCHOLOGY
DAVID G. MYERS | C. NATHAN DEWALL
Chapter Overview
Studying and Encoding Memories
Storing and Retrieving Memories
Forgetting, Memory Construction, and Improving Memory
Studying and Encoding Memories
Memory
Persistence of learning over time through the encoding, storage, and retrieval of information
Evidence of memory
Recalling information
Recognizing it
Relearning it more easily on a later attempt
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Measuring Retention
Three measures of memory retention:
Recall: A measure of memory in which the person must retrieve information learned earlier, as on a fill-in-the-blank test.
Recognition: A measure of memory in which the person identifies items previously learned, as on a multiple-choice test.
Relearning: A measure of memory that assesses the amount of time saved when learning material again.
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Ebbinghaus’ Retention Curve
Ebbinghaus found that the more times he practiced a list of nonsense syllables on day 1, the less time he required to relearn it on day 2. Speed of relearning is one measure of memory retention (Baddeley, 1982).
Tests of recognition and of time spent relearning demonstrate that we remember more than we can recall.
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Memory Models (part 1)
Psychologists use memory models to think and communicate about memory.
Information-processing model
Compares human memory to computer operations
Involves three processes: encoding, storage, and retrieval
Connectionism information-processing model
Focuses on multitrack, parallel processing—the processing of many aspects of a problem simultaneously
Views memories as products of interconnected neural networks
Encoding: Process of getting information into the memory system.
Storage: Process of retaining encoded information over time.
Retrieval: Process of getting information out of memory storage.
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Memory Models (part 2)
Three processing stages in the classic Atkinson-Shiffrin (1968) model:
We record to-be-remembered information as a fleeting sensory memory, the immediate, very brief recording of sensory information.
We then process information into short-term memory (activated memory that holds a few items briefly), where we encode it through rehearsal.
Finally, information moves into long-term memory, the relatively permanent and limitless storehouse of the memory system of knowledge, skills, and experiences, for later retrieval.
Sensory memory: The immediate, very brief recording of sensory information in the memory system.
Short-term memory: Activated memory that holds a few items briefly, such as the seven digits of a phone number while calling, before the information is stored or forgotten,
Long-term memory: The relatively permanent and limitless storehouse of the memory system; includes knowledge, skills, and experiences.
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A Modified Three-Stage Processing Model of Memory
Atkinson and Shiffrin’s classic three-step model helps us to think about how memories are processed, but today’s researchers recognize other ways that long-term memories form. For example, some information slips into long-term memory via a “back door,” without our consciously attending to it (automatic processing). Also, so much active processing occurs in the short-term memory stage that many now prefer the term working memory.
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Memory Models (part 3)
Working memory
Stresses the active processing occurring in the second memory stage
Is a newer understanding of short-term memory that adds conscious, active processing of incoming auditory and visual-spatial information, and of information retrieved from long-term memory
In Baddeley’s (2002) model, this focused processing is handled by a central executive.
Encoding Memories
Dual-Track Memory: Effortful Versus Automatic Processing
Explicit memory (declarative memory): Memory of facts and experiences that one can consciously know and “declare.” We encode explicit memories through conscious effortful processing.
Implicit memory (nondeclarative memory): Retention of learned skills or classically conditioned associations independent of conscious recollection. We encode implicit memories through automatic processing, without our awareness.
Automatic Processing and Implicit Memories
(part 1)
Implicit memories include procedural memory for automatic skills and classically conditioned associations among stimuli
Information is automatically processed about:
Space
Time
Frequency
Automatic Processing and Implicit Memories
(part 2)
Automatic processing happens effortlessly.
With experience and practice, learned skills such as reading and driving become automatic.
Many skills are developed this way.
Effortful Processing and Explicit Memories
Sensory memory
Sensory memory feeds our active working memory, recording momentary images of scenes or echoes of sounds.
Two types of sensory memory are iconic memory and echoic memory.
Sensory Memory
Sensory memory: First stage in forming explicit memories
Iconic memory: Picture-image memory of visual stimuli lasting no more than a few tenths of a second
Echoic memory: Sound memory of auditory stimuli; can be recalled within 3 or 4 seconds
Total Recall—Briefly
When George Sperling (1960) flashed a group of letters similar to this for one-twentieth of a second, people could recall only about half the letters. But when signaled to recall any one row immediately after the letters had disappeared, they could do so with near-perfect accuracy.
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Short-Term Memory Capacity
Short-term memory holds a few items briefly (such as the seven digits of a phone number while dialing) before the information is stored or forgotten.
George Miller (1956) proposed the magical number 7: People can store about seven bits of information (give or take two).
Baddeley and colleagues (1975) have confirmed that without distraction, we can recall about seven digits or about six letters or five words.
Capacity varies by age and distractions at the time of memory tasks.
Effortful Processing Strategies
Chunking: Organization of items into familiar, manageable units; often occurs automatically.
Mnemonics: Memory aids, especially techniques that use vivid imagery and organizational devices.
The peg-word system harnesses our superior visual-imagery skill.
Hierarchies: Organization of items into a few broad categories that are divided and subdivided into narrower concepts and facts.
Distributed Practice
Spacing effect: Encoding is more effective when it is spread over time.
Distributed practice produces better long-term retention than is achieved through massed study or practice.
Massed practice produces speedy short-term learning and feelings of confidence, but leads to quick forgetting.
Testing effect:
Enhanced memory after retrieving, rather than simply rereading, information.
Repeated self-testing (using the Retrieve It and Testing Effect questions in this text, for example) does more than assess learning: It improves it.
Practice may not make perfect, but smart practice—occasional rehearsal with self-testing—makes for lasting memories.
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Levels of Processing
Verbal information is processed at different levels, which affects long-term retention.
Shallow processing encodes on a very basic level (a word’s letters) or on a more intermediate level (a word’s sound).
Deep processing encodes semantically, based on word meaning.
The deeper (more meaningful) the processing, the better our retention.
Making Material Personally Meaningful
New information is processed easily when it is meaningful or related to our experience.
Ebbinghaus estimated that learning meaningful material requires one-tenth of the effort compared with learning nonsense material.
We have especially good recall for information we can relate to ourselves—a tendency referred to as the self-reference effect.
The amount of information remembered depends both on the time spent in learning it and on your making it meaningful for deep processing.
Memory Storage
Our capacity for storing long-term memories is essentially limitless.
This is contrary to the belief that we can add more items only if we discard old ones.
Retaining Information in the Brain (part 1)
Despite the brain’s vast storage capacity, we do not store information as libraries store their books, in single, precise locations.
Instead, brain networks encode, store, and retrieve the information that forms our complex memories. That is, the brain distributes the components of a memory across a network of locations in the brain.
Some of the brain cells that fired when we experienced something fire again when we recall it.
Retaining Information in the Brain (part 2)
We have two conscious memory systems:
Semantic memory: Explicit memory of facts and general knowledge
Episodic memory: Explicit memory of personally experienced events.
Hippocampus: A neural center located in the limbic system, which registers and temporarily holds elements of explicit memories before moving them to other brain regions for long-term storage
Memory consolidation: Neural storage of long-term memories
Explicit-Memory System: The Hippocampus
Explicit memories for facts and episodes are processed in the hippocampus (orange structures) and fed to other brain regions for storage.
The Hippocampus
Separate brain regions process explicit and implicit memories.
During sleep, the hippocampus and brain cortex display rhythmic patterns of activity, as if they were talking to each other (Euston et al., 2007; Mehta, 2007). Researchers suspect that the brain is replaying the day’s experiences as it transfers them to the cortex for long-term storage.
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Implicit Memory System: Cerebellum and Basal Ganglia
The cerebellum plays an important role in forming and storing implicit memories created by classical conditioning.
The basal ganglia—deep brain structures involved in motor movement—facilitate formation of our procedural memories for skills.
Infantile amnesia
Conscious memory of the first three years is blank.
Command of language and a well-developed hippocampus is needed for such memory.
The hippocampus is one of the last brain structures to mature.
The Amygdala, Emotions, and Memory
Excitement or stress triggers hormone production and provokes the amygdala (two emotion-processing clusters in the limbic system) to engage memory.
Emotions often persist with or without conscious awareness.
Emotional arousal causes an outpouring of stress hormones; the hormones lead to activity in the brain’s memory-forming areas.
Flashbulb memories—clear memories of emotionally significant moments or events—occur via emotion-triggered hormonal changes and rehearsal.
Key Memory Structures in the Brain
Frontal lobes and hippocampus: Explicit memory formation
Cerebellum and basal ganglia: Implicit memory formation
Amygdala: Emotion-related memory formation
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Synaptic Changes
Long-term potentiation (LTP)
Increase in a synapse’s firing potential after brief, rapid stimulation
After LTP, the brain will not erase memories
Believed to be a neural basis for learning and memory
Kandel and Schwartz (1982):
Observed synaptic changes during learning in the neurons of the California sea slug, Aplysia.
Pinpointed changes in sea slugs’ neural connections: With learning, more serotonin is released and cell efficiency is increased.
Aplysia
Aplysia, the California sea slug, which neuroscientist Eric Kandel studied for 45 years, has increased our understanding of the neural basis of learning and memory.
After LTP has occurred, an electric current passing through the brain won’t erase old memories—but the same current will wipe out very recent memories.
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Doubled Receptor Sites
Electron microscope image (a) shows just one receptor site (gray) reaching toward a sending neuron before long-term potentiation. Image (b) shows that, after LTP, the receptor sites have doubled. This means that the receiving neuron has increased sensitivity for detecting the presence of the neurotransmitter molecules that may be released by the sending neuron. (From Toni et al., 1999.)
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Our Two Memory Systems
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Memory Retrieval: Retrieval Cues
Memories are held in storage by a web of associations.
Retrieval cues serve as anchor points for pathways to memory suspended in this web.
When you encode into memory the name of the person sitting next to you in class, you associate it with other bits of information about your surroundings, mood, seating position, and so on.
The best retrieval cues come from associations formed at the time a memory is encoded.
Priming: Activation, often unconsciously, of particular associations in memory.
Retrieval Cues (part 1)
Priming
After seeing or hearing rabbit, we are later more likely to spell the spoken word hair/hare as h-a-r-e (Bower, 1986).
Associations unconsciously activate related associations.
Figure 8.13
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Retrieval Cues (part 2)
Context-dependent memory
Recall of specific information improves when the contexts present at encoding and retrieval are the same.
Cues and contexts specific to a particular memory will be most effective in helping recall.
Retrieval Cues (part 3)
State-dependent memory
Emotions that accompany good or bad events become retrieval cues.
Mood-congruent memory: The tendency to recall experiences that are consistent with one’s current good or bad mood.
Passions are exaggerated:
In a bad mood, we may read someone’s look as a glare and feel even worse.
In a good mood, we may encode the same look as interest and feel even better.
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The Serial Position Effect
Serial position effect: Our tendency to recall best the last (recency effect) and first (primacy effect) items in a list.
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Why Do We Forget?
William James (1890): “If we remembered everything, we should on most occasions be as ill off as if we remembered nothing.”
It’s surely a blessing that most of us discard the clutter of useless or out-of-date information—but our sometimes unpredictable memory can be frustrating.
Anterograde amnesia: Inability to form new memories.
Retrograde amnesia: Inability to retrieve information from one’s past.
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When Do We Forget?
Forgetting can occur at any memory stage.
When we process information, we filter, alter, or lose most of it.
Encoding Failure
Much of what we sense, we never notice.
What we fail to encode, we will never remember.
Age: Encoding lag is linked to age-related memory decline.
Attention: Failure to notice or encode contributes to memory failure,
You have surely seen the Apple computer logo thousands of times. Can you draw it? In one study, only 1 of 85 UCLA students (including 52 Apple users) could do so accurately (Blake et al., 2015). Without encoding effort, many potential memories never form.
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Forgetting as Encoding Failure
We cannot remember what we have not encoded.
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Storage Decay
Even after encoding something well, we sometimes later forget it.
The course of forgetting is initially rapid, but then levels off with time.
Physical changes in the brain occur as memory forms (memory trace).
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Ebbinghaus’ Forgetting Curve
After learning lists of nonsense syllables, such as YOX and JIH, Ebbinghaus studied how much he retained up to 30 days later. He found that memory for novel information fades quickly, then levels out. (Data from Ebbinghaus, 1885.)
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Retrieval Failure (part 1)
Sometimes even stored information cannot be accessed, which leads to forgetting.
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Retroactive Interference
More forgetting occurred when a person stayed awake and experienced other new material.
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Retrieval Failure (part 2)
Interference
Proactive (forward-acting) interference: Prior learning disrupts recall of new information.
Retroactive (backward-acting) interference: New learning disrupts recall of older information.
Motivated forgetting
Sigmund Freud argued that we repress painful or unacceptable memories to protect our self-concept and to minimize anxiety.
Today’s researchers think repression rarely, if ever, occurs.
Forgetting is more likely when information is neutral, not emotional; we often have intrusive memories of the very same traumatic experiences we would most like to forget.
Repression: In psychoanalytic theory, the basic defense mechanism that banishes from consciousness anxiety-arousing thoughts, feelings, and memories.
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Memory Construction Errors (part 1)
Memory is not precise. We don’t just retrieve memories, we reweave them.
Elizabeth Loftus and Katherine Ketcham (1994): “Our memories are flexible and superimposable, a panoramic blackboard with an endless supply of chalk and erasers.”
Reconsolidation: A process in which previously stored memories, when retrieved, are potentially altered before being stored again.
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Misinformation and Imagination Effects
Misinformation effect: Corruption of a memory by misleading information.
Even repeatedly imagining fake actions and events can create false memories.
Digitally altered photos can produce imagination inflation—that is, memories of events that people have not actually experienced.
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Memory Construction
In this experiment, people viewed a film clip of a car accident (left). Those who later were asked a leading question recalled a more serious accident than they had witnessed (Loftus & Palmer, 1974).
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Memory Construction Errors (part 2)
Source amnesia (source misattribution): Attributing to the wrong source an event we have experienced, heard about, read about, or imagined.
Source misattribution, along with the misinformation effect, is at the heart of many false memories.
Déjà vu: That eerie sense that “I’ve experienced this before.” Cues from the current situation may unconsciously trigger retrieval of an earlier experience.
Discerning True and False Memories
False memories feel like real memories and can be persistent, but are usually limited to the gist of the event.
False memories are often a result of faulty eyewitness testimony.
Memory construction helps explain:
Why dating partners who have fallen in love overestimate their first impressions of each other.
Why people asked how they felt 10 years ago about certain social issues recall attitudes closer to their current views than to the views they actually reported a decade earlier.
Children’s Eyewitness Recall
Studies by Ceci and Bruck (1993, 1995):
The effect of suggestive interviewing techniques.
How easily children’s memories can be molded: In one study, 58 percent of preschoolers produced false stories about one or more unexperienced events.
Children can often accurately recall events when nonleading questions are asked by a neutral person, in words the children can understand, and the questions are asked soon after the event (ideally before children have talked much to involved adults).
Can Memories of Childhood Sexual Abuse Be Repressed and Then Recovered? (part 1)
The debate between memory researchers and some well-meaning therapists focuses on whether most memories of early childhood abuse are repressed and can be recovered during therapy using “memory work” techniques that may involve “guided imagery,” leading questions, hypnosis, or dream analysis.
Two tragedies of child abuse:
When people don’t believe abuse survivors
When innocent people are falsely accused
There’s a need to find a sensible common ground.
Can Memories of Childhood Sexual Abuse Be Repressed and Then Recovered? (part 2)
Those committed to protecting abused children and those committed to protecting wrongly accused adults have agreed on the following points:
Sexual abuse happens.
Injustice happens.
Forgetting happens.
Recovered memories are commonplace, but this doesn’t necessarily mean the unconscious mind repressed them.
Memories of things happening before age 3 are unreliable.
Memories “recovered” under hypnosis or the influence of drugs are especially unreliable.
Memories, whether real or false, can be emotionally upsetting.
Improving Memory
The SQ3R (Survey, Question, Read, Retrieve, Review) study technique used in this book incorporates several learning strategies:
Rehearse repeatedly.
Make the material meaningful.
Activate retrieval cues.
Use mnemonic devices.
Minimize interference.
Sleep more.
Test your own knowledge, both to rehearse it and to find out what you do not yet know.
