Chapter 9: Intelligence and Psychological Testing Slides
– Key Concepts in Psychological Testing
Standardization refers to the uniform procedures used in the
administration and scoring of a test.
o Test norms provide information about where a score on a
psychological test ranks in relation to other scores on that
test…allows a psychologist to determine how a person scores
relative to other people.
o The standardization group is the sample of people that the
norms are based on.
Reliability refers to a test‟s consistency; that is, repeated measurements
should yield reasonably similar results.
o Reliability estimates are based on the correlation coefficient.
Two sets of scores from two administrations of the same test
are correlated; the closer the correlation comes to +1.00, the
more reliable the test.
Validity refers to the ability of a test to measure what it was designed to
o Content validity is the degree to which the content of a test is
representative of the domain it is supposed to cover (physics
questions on a psychology test…poor content validity).
o Criterion-related validity is estimated by correlating subjects‟
scores on a test with their scores on an independent
o Construct validity is the extent to which there is evidence that
a test measures a particular hypothetical construct…are we
really measuring intelligence with an IQ test? –
– Principal Types of Psychological Tests
– Psychological tests are standardized measures of behaviour. Most
psychological tests fall under two broad categories, mental ability tests
and personality scales.
Mental ability tests
Mental ability tests include intelligence tests, which are designed to
measure general mental ability, and aptitude tests, which measure
more specific mental abilities.
o Intelligence – general
o Aptitude – specific
Personality measures are usually called scales, rather than tests, as
there are no right or wrong answers.
Personality tests measure a variety of motives, interests, values,
o Measure motives, interests, values, and attitudes
– Fig 9.2 – Correlation and reliability. As explained in Chapter 2, a
positive correlation means that two variables covary in the same
direction; a negative correlation means that two variables covary in the
opposite direction. The closer the correlation coefficient gets to either –
1.00 or +1.00, the stronger the relationship. At a minimum, reliability
estimates for psychological tests must be moderately high positive
correlations. Most reliability coefficients fall between 0.70 and 0.95. –
– Fig 9.3 – Criterion-related validity. To evaluate the criterion-related
validity of a pilot aptitude test, a psychologist would correlate subjects’
test scores with a criterion measure of their aptitude, such as ratings of
their performance in a pilot training program. The validity of the test is
supported if a substantial correlation is found between the two measures.
If little or no relationship exists between the two sets of scores, the data
do not provide support for the validity of the test.
– Fig 9.4 – Construct validity. Psychologists evaluate a scale’s construct
validity by studying how scores on the scale correlate with a variety of variables. For example, some of the evidence on the construct validity of
the Expression Scale from the Psychological Screening Inventory is
summarized here. This scale is supposed to measure the personality trait
of extraversion. As you can see on the left side of this network of
correlations, the scale correlates negatively with measures of social
introversion, social discomfort, and neuroticism, just as one would expect
if the scale is really tapping extraversion. On the right, you can see that
the scale is correlated positively with measures of sociability and self-
acceptance and another index of extraversion as one would anticipate. At
the bottom, you can see that the scale does not correlate with several
traits that should be unrelated to extraversion. Thus, the network of
correlations depicted here supports the
– idea that the Expression Scale measures extraversion.
– The Evolution of Intelligence Testing
Sir Francis Galton (1869)
Sir Francis Galton, 1869, published Hereditary Genius, in which he
put forth the notion that success runs in families because
intelligence is inherited. He developed a crude mental abilities test
based on sensory acuity.
Alfred Binet and Theodore Simon (1905)
Alfred Binet and Theodore Simon published the first intelligence test
in 1905, a test designed to single out youngsters in need of special
training…expressed a child‟s score in terms of mental age…for
example, a 4 year old child with a mental age of 6 performed like
the average 6 year-old on the test.
Binet-Simon Intelligence Scale
Lewis Terman (1916)
Lewis Terman, at Stanford University, revised Binet‟s test for use in
the U.S….the Stanford-Binet.
Terman used a new scoring scheme, the intelligence quotient,
dividing a child‟s mental age by chronological age and multiplying
by 100…this made it possible to compare children of different ages. Stanford-Binet Intelligence Scale
Intelligence Quotient (IQ) = MA/CA x 100
David Wechsler (1955)
David Wechsler was the fist to devise an instrument to measure
intelligence in adults. He later devised downward extensions of his
scale for children. Wechsler is credited with two innovations in
intelligence testing. First, his scales give more emphasis to
nonverbal reasoning, yielding a verbal IQ, a performance IQ, and a
full-scale IQ. Second, Wechsler devised a new scoring system
based on the normal distribution…the deviation IQ. This scoring
system is outlined on the next slide.
Wechsler Adult Intelligence Scale
– Fig 9.7 – Subtests on the Wechsler Adult Intelligence Scale
(WAIS). The WAIS is subdivided into a series of tests that yield
separate verbal and performance (nonverbal) IQ scores. Examples of
low-level (easy) test items that closely resemble
– those on the WAIS are shown on the right.
– Fig 9.8 – The normal distribution. Many characteristics are distributed
in a pattern represented by this bell-shaped curve. The horizontal axis
shows how far above or below the mean a score is (measured in plus or
minus standard deviations). The vertical axis is used to graph the number
of cases obtaining each score. In a normal distribution, the cases are
distributed in a fixed pattern. For instance, 68.26% of the cases fall
between +1 and –1 standard deviation. Modern IQ scores indicate where
a person’s measured intelligence falls in the normal distribution. On most
IQ tests, the mean is set at an IQ of 100 and the standard deviation at
15. Thus, an IQ of 130 means that a person scored 2 standard deviations
above the mean. Any deviation IQ score can be converted into a
percentile score, which indicates the percentage of cases obtaining a lower score. The mental classifications at the bottom of the figure are
descriptive labels that roughly correspond to ranges of IQ scores.
– Validity of IQ Tests
Are IQ Tests Valid?
Sternberg's (1981) categories:
Which do IQ tests measure?
Stanovich (2009) criticisms
– Reliability and Validity of IQ Tests
Exceptionally reliable – correlations into the .90s
Qualified validity – valid indicators of academic/verbal intelligence, not
intelligence in a truly general sense
.40s-.50s with school success
.60s-.80s with number of years in school
Predictive of occupational attainment, debate about predictiveness of
Although they are intended to measure potential, IQ tests inevitably
assess both knowledge and potential.
IQ tests are, however, exceptionally reliable, with reliability coefficients
into the .90s.
IQ tests are reasonably valid indicators of academic intelligence, as they
predict school success and number of years in school.
They are not good measures of social or practical intelligence and do not
measure intelligence in a truly general sense.
IQ scores are positively correlated with high status jobs; this may be
related to the correlation with school success.
There is conflicting evidence regarding whether IQ scores predict
occupational performance. Court rulings and laws now require that tests used in selection of employees measure specific abilities related to job
– Stability and Culture
Stability not seen in infancy/preschool ages
Scores are stable around ages 7 yrs +
Changes can occur (e.g. Headstart Programs)
Used in Western Cultures and not in non-Western Cultures
– Extremes of Intelligence: Mental Retardation
Diagnosis based on IQ and adaptive testing
IQ 2 or more SD below mean
Adaptive skill deficits
Origination before age 18
4 levels: mild, moderate, severe, profound
Mild most common by far
Environmental vs. Biological
Mental retardation is a diagnosis reserved for individuals with subaverage
general mental ability accompanied by deficiencies in adaptive skills,
originating before age 18.
The vast majority of people with mental retardation have mild mental
retardation and are not easily distinguished from the rest of the
Origins of mental retardation may include organic syndromes, as 350
biological conditions that can cause mental retardation have been
identified. Diagnosticians are, however, only able to pin down an organic
cause in <25% of cases.
In fact, cases of mild mental retardation tend to involve unknown origin.
Environmental theories hold that unfavorable environmental factors may
contribute to the development of mild mental retardation; things like
neglect, inadequate nutrition and medical care, and lower quality
– Fig 9.10 – The prevalence and severity of mental retardation. The
overall prevalence of mental retardation is roughly 1 to 3% of the general
population. The vast majority (85%) of the retarded population is mildly
retarded. Only about 15% of the retarded population falls into the
subcategories of moderate, severe, or profound retardation.
– Fig 9.11 – Social class and mental retardation. This graph charts the
prevalence of mild retardation (IQ 60 to 69) and more severe forms of
retardation (IQ below 50) in relation to social class. Severe forms of
retardation are distributed pretty evenly across the social classes, a
finding that is consistent with the notion that they are the product of
biological aberrations that are equally likely to strike anyone. In contrast,
the prevalence of mild retardation is greatly elevated in the lower social
classes, a finding that meshes with the notion that mild retardation is
largely a product of unfavorable environmental factors. (Source: Adapted
from Popper and Steingard, 1994) –
– Extremes of Intelligence: Giftedness
Identification issues – ideals vs. practice
IQ 2 SD above mean standard
Creativity, leadership, special talent?
Stereotypes – weak, socially inept, emotionally troubled
Lewis Terman (1925) – largely contradicted stereotypes
o Lewis Terman initiated a study in the early 1920‟s with 1500
children with IQs of 150 or higher. These children were
followed throughout their lives. As a group, these subjects
exhibited better than average physical health, emotional
stability, and social satisfaction through their adult years.
Ellen Winner (1997) – moderately vs. profoundly gifted
o Ellen Winner (1997) claims that a distinction needs to be
made between moderately gifted (IQ 130-150) and
profoundly gifted (IQ above 180) individuals, asserting that
profoundly gifted children are often introverted and isolated.
Giftedness and high achieving – beyond IQ
Renzulli (2002) – intersection of three factors
Simonton (2001) – drudge theory and inborn talent
There are discrepancies between ideals and practice regarding how gifted
children are identified in the U.S. Usually, identification occurs based on
IQ of 130 or higher, although creativity, leadership, and special talents
are recommended for use in identification as well.
Gifted individuals are often stereotyped as weak, sickly, socially inept,
and emotionally troubled “bookworms.”
Studies of giftedness and achievement in life suggest that more than IQ
determines high achievement. Joseph Renzulli theorizes that there is a
more rare form of giftedness, based in an intersection of 3 factors, that
leads to genuine greatness…high intelligence, high creativity, and high
Drudge theory is captured in the reaction of one talented violinist after a
critic termed him a genius – “A genius! For 37 years I‟ve practiced
fourteen hours a day, and now they call me a genius!” – While clearly obsessive hard work is important in this case, it can be argued that
inborn ability allowed him to work harder because he found his efforts
more rewarding. Simonton proposes an elaborate theory of talent
development that gives roles to both innate ability and environmental
– Intelligence: Heredity or Environment?
Family and twin studies
Cumulative deprivation hypothesis
The Flynn effect
The concept of the reaction range
This issue has far-reaching sociopolitical implications and continues to be
a complex controversy.
Family studies determine only whether genetic influence on a trait is
plausible, not whether it is certain. Family members also share
Twin studies provide evidence regarding the role of genetic factors. The
basic rationale is that identical and fraternal twins develop under similar
environmental conditions, but identical twins share more genes…if
identical twins end up more similar on a given characteristic, it must be
A heritability ratio is an estimate of the proportion of trait variability in a
population that is determined by variations in genetic inheritance. A
heritability estimate is a group statistic and cannot be meaningfully
applied to individuals.
Adoption studies provide evidence that upbringing plays an important role
in mental ability, as adopted children show some resemblance to their
foster parents. Also, siblings reared together are more similar in IQ than
siblings reared apart. In fact, entirely unrelated children who are reared
together show resemblance in IQ. The cumulative deprivation hypothesis holds that children raised in
deprived environments will experience a gradual decline in IQ as they
grow older. Conversely, children removed from deprived environments
and placed in homes that are more conducive for learning show IQ
The Flynn effect is the trend, all over the developed world, for IQ scores
to increase from one generation to the next. Hypotheses for why this
occurs focus on environmental variables, as evolution does not operate in
Clearly, heredity and environment both influence intelligence. Theorists
use the term “reaction range” to refer to genetically determined limits on
IQ. The environment determines whether a person will fall at the upper or
lower end of their genetically determined range.
– Fig 9.13 – Studies of IQ similarity. The graph shows the mean
correlations of IQ scores for people of various types of relationships, as
obtained in studies of IQ similarity. Higher correlations indicate greater
similarity. The results show that greater genetic similarity is associated
with greater similarity in IQ, suggesting that intelligence is partly inherited (compare, for example, the correlations for identical and
fraternal twins). However, the results also show that living together is
associated with greater IQ similarity, suggesting that intelligence is partly
governed by environment (compare, for example,
– the scores of siblings reared together and reared apart). (Data from
McGue et al., 1993)
– Fig 9.14 – The concept of heritability. A heritability ratio is an
estimate of the portion of variation in a trait determined by heredity—
with the remainder presumably determined by environment—as these pie
charts illustrate. Typical heritability estimates for intelligence range
between a high of 70% and a low of 50%, although some estimates have
fallen outside this range. Bear in mind that heritability ratios are
estimates and have certain limitations that are discussed in the text.
– Fig 9.16 – Reaction range. The concept of reaction range posits that
heredity sets limits on one’s intellectual potential (represented by the
horizontal bars), while the quality of one’s environment influences where
one scores within this range (represented by the dots on the bars).
People raised in enriched environments should score near the top of their
reaction range, whereas people raised in poor-quality environments
should score near the bottom of their range. Genetic limits on IQ can be
inferred only indirectly, so theorists aren’t sure whether reaction ranges
are narrow (like Ted’s) or wide (like Chris’s). The concept of reaction
range can explain how two people with similar genetic potential can be
quite different in intelligence (compare Tom and Jack) and how two
people reared in environments of similar quality can score quite
differently (compare Alice and Jack).
– Cultural Differences in IQ
Heritability as an Explanation
Aurthur Jensen (1969)
o Arthur Jensen argued that cultural differences in average IQ
are largely due to heredity.
Herrnstein and Murray (1994) – The Bell Curve o The authors of The Bell Curve, by implying that we are
moving toward a meritocracy based on intellect, ignited the
o These arguments have been challenged on a number of
grounds. First, even if IQ is largely due to heredity, group
differences may not be. Social class and socioeconomic
disadvantage are correlated with ethnicity, so environmental
variables are not equal between groups.
Rushton ―Race, Evolution, and Behaviour‖
o Philippe Rushton‟s book Race, Evolution, and Behavior (1995)
argued that genetics were the cause for intellectual and
behavioural differences between cultural groups. His book
was criticized as being based on bad science, sloppy
reasoning, and inaccuracies.
Environment as an Explanation
Kamin’s cornfield analogy – socioeconomic disadvantage
o Kamin‟s cornfield analogy, presented on the next slide,
depicts this issue.
Steele (1997) - stereotype vulnerability
o Claude Steele argues that derogatory stereotypes create
feelings of vulnerability in the educational domain,
undermining group members‟ achievement and performance
on tests. –
– Fig 9.17 – Genetics and between-group differences on a trait.
Kamin’s analogy (see text) shows how between-group differences on a
trait (the height of corn plants) could be due to environment, even if the
trait is largely inherited. The same reasoning presumably applies to ethnic
group differences in the trait of human intelligence.
– New Directions in the Study of Intelligence
Increased emphasis on specific abilities
Moving beyond Spearman’s g
Guilford’s 150 distinct mental abilities. o Increased emphasis is being placed on specific abilities rather
than a general mental ability that Charles Spearman labeled
g. Spearman used a statistical procedure called factor
analysis to determine intercorrelated, specific mental talents
(s) (concluding that all cognitive abilities share a common
core). In contrast, J.P. Guilford asserts that intelligence is
made up of as many as 150 distinct mental abilities.
Fluid vs. crystallized intelligence
o Cattell and Horn suggest that g should be divided into fluid
intelligence, which consists of reasoning ability, memory
capacity, speed of information processing, and crystallized
intelligence, which consists of the ability to apply acquired
knowledge and skills in problem solving.
Biological Indexes of Intelligence
Reaction time and inspection time
o Other researchers, such as Aurthur Jensen, are searching for
physiological indicators of general intelligence. Reaction time
has been used in these studies, although the “fast is smart”
idea is modest at best. Other measures studied include
inspection time, which is an assessment of how long it takes
to make simple perceptual discriminations that meet a certain
criterion of accuracy. Higher correlations with IQ have been
found with this measure, although much work remains to be
done to discover why.
Cognitive Conceptualizations of Intelligence
Sternberg’s triarchic theory and successful intelligence
o For over a century, intelligence was approached from a
testing perspective. In contrast, the cognitive perspective
focuses on how people use their intelligence. Robert
Sternberg‟s triarchic theory of intelligence consists of three
parts: the contextual, experiential, and componential
subtheories. In more recent years (1999, 2000), Sternberg
has asserted that there are three aspects of what he calls
“successful intelligence” – analytical intelligence, creative
intelligence, and practical intelligence.
Expanding the Concept of Intelligence Gardner’s multiple intelligences
o Other theorists propose an expansion of the concept of
intelligence. Howard Gardner argues that IQ tests emphasize
verbal and mathematical skills and exclude other important
skills. He suggests the existence of a number of human
intelligences, listed in Table 9.3.
Goleman’s emotional intelligence
o Daniel Goleman and others argue for the concept of emotional
intelligence, which is the ability to perceive and express
emotion, assimilate emotion in thought, understand and
reason with emotion, and regulate emotion.
– Fig 9.5 – Spearman’s g. In his analysis of the structure of intellect,
Charles Spearman found that specific mental talents (S1, S2, S3, and so
on) were highly intercorrelated. Thus, he concluded that all cognitive
abilities share a common core, which he labeled g for general mental
– Fig 9.6 – Guilford’s model of mental abilities. In contrast to
Spearman (see Figure 9.18), J. P. Guilford concluded that intelligence is
made up of many separate abilities. According to his analysis, people may
have as many as 150 distinct mental abilities that can be characterized in
terms of the operations, contents, and products of intellectual activity. –
– Fig 9.20 – Sternberg’s triarchic theory of intelligence. Sternberg’s
model of intelligence consists of three parts: the contextual subtheory,
the experiential subtheory, and the componential subtheory. Much of
Sternberg’s research has been devoted to the componential subtheory, as
he has attempted to identify the cognitive processes that contribute to
intelligence. He believes that these processes fall into three groups:
metacomponents, performance components, and knowledge-acquisition
Divergent vs. Convergent thinking
Remote Associates Test (1967)
Personality, Intelligence & Mental Illness
– Chapter 10: Motivation and Emotion Slides
– Motivational Theories and Concepts
Motives – needs, wants, desires leading to goal-directed behavior
Motives are the needs, wants, interests, and desires that propel
people toward behaviour.
Drive theories – seeking homeostasis
Drive theories hold that motivation is based in an internal state of
tension that motivates an organism to engage in activities that
should reduce this tension…organisms seek to maintain
homeostasis, or a state of equilibrium or stability.
Incentive theories – regulation by external stimuli
Incentive theories hold that motivation is regulated by external
stimuli…ice cream, an A, money, etc.
Evolutionary theories – maximizing reproductive success
Evolutionary theories hold that natural selection favors behaviours
that maximize reproductive success…explains affiliation,
achievement, dominance, aggression, and sex drive in terms of
– – The Motivation of Hunger and Eating: Biological Factors
Lateral and ventromedial hypothalamus
o Research in the 40‟s and 50‟s showed that the hypothalamus,
particularly two areas called the lateral hypothalamus (LH)
and the ventromedial nucleus of the hypothalamus (VMH),
are important in hunger. The LH was thought to be the
hunger center, while the VMH was thought to be the satiety
center. Subsequent research indicated that this was an
oversimplified picture, although the LH and VMH are part of
the hunger circuit, they are not the key elements.
o The paraventricular nucleus of the hypothalamus has recently
been implicated as another influential part of the hunger
Glucose and digestive regulation
o Other research has focused on the role of blood glucose and
digestive regulation on hunger; when blood sugar goes down,
hunger goes up. Glucostatic theory proposed that fluctuations
in blood glucose level are monitored in the brain by glucostats
– neurons sensitive to glucose in the surrounding fluid. It
appears likely that hunger is regulated, in part, through
Insulin and leptin
o Hormones circulating in the blood also appear to be related to
hunger. Insulin, secreted by the pancreas, must be present
for cells to use blood glucose. Increases in insulin increase
hunger, and the mere sight and smell of food has been shown
to increase insulin.
o Recently, a new hormone, leptin, has been discovered to be
released from fat cells into the bloodstream. Leptin is believed
to signal the hypothalamus about fat stores in the body,
causing decreases in hunger when fat stores are high. In the early 1900‟s, Walter Cannon and A.L. Washburn hypothesized that
there is an association between stomach contractions and the experience
of hunger; Cannon hypothesized a causal relationship, yet people who
have their stomachs removed still experience hunger. This realization led
to more complicated theories focusing on the brain, blood sugar, and
– – Fig 10.3 – The hypothalamus. This small structure at the base of the
forebrain plays a role in regulating a variety of human biological needs,
including hunger. The detailed blowup shows that the hypothalamus is
made up of a variety of discrete areas. Scientists used to believe that the
lateral and ventromedial areas were the brain’s start and stop centres for
eating. However, more recent research suggests that the paraventricular
nucleus is more crucial to the regulation of hunger.
– The Motivation of Hunger and Eating: Environmental Factors
Learned preferences and habits
When, as well as what
Clearly, hunger is related to biology; however, it is also regulated
by environmental factors like learned preferences. Studies show
that people like foods that are familiar to them; dog meat is a
delicacy in some parts of the world. Exposure and observational
learning appear to play a part in what we like to eat. Learning also
appears to influence when and how much people eat.
Appearance, odour, effort required
Food related cues are environmental cues that have been
associated with eating, such as the appearance or odor of food, the
effort required to eat a particular food, etc. Research shows that
these external cues influence eating behaviour to some extent,
beyond biological hunger.
Link between heightened arousal/negative emotion and overeating
Finally, stress has been shown to be related to increased eating,
with some research indicating that chronic dieters are more likely to
respond to stress with eating. It is unclear whether stress induced
eating is caused by physiological arousal or negative emotion. It is
also unclear whether the effects of stress on hunger are direct or
– Eating and Weight: The Roots of Obesity –
Body Mass Index and adoption study
The concept of set point/settling point
Excessive Eating/Inadequate Exercise, Dietary restraint
Obesity is the condition of being overweight. Criteria differ, but one
definition assumes that people are overweight if their weight exceeds
their ideal body weight by 20%.
Obesity is a significant health problem, elevating mortality risk.
Evolutionary explanations for increases in the prevalence of obesity are
based in food supply changes. Whereas most animals evolved in
environments where competition for food was fierce and food supplies
were unreliable, the vast majority of humans now live in environments
where food is abundant and reliable.
Research suggests that some people can eat more than others without
gaining weight and that this may have a genetic basis. When adults
raised by foster parents are compared to biological and foster parents in
regard to BMI (weight in kilograms divided by height in meters, squared),
adoptees resemble biological parents, not adoptive. Twin studies suggest
that genetic factors account for 61% of the variation in body weight
among men and 73% among women.
Lose weight on a diet, gain it back. The reverse is also true. Intentionally
put on weight and have a hard time keeping it on. Richard Keesy, 1995,
suggests that our bodies have a set point, or natural point of stability in
body weight. This appears to be related to fat cell levels…when fat stores
slip below a crucial level, hunger increases and metabolism decreases.
Settling-point theory (Pinel, et al., 2000) alternatively proposes that
weight hovers near the level at which the constellation of factors that
determine food consumption and energy expenditure achieve an
equilibrium. Thus, according to this theory, weight remains stable as long
as there are no durable changes in any of the factors that influence it.
Researchers have also shown that dietary restraint may contribute to
obesity. Chronic dieters restrain themselves from eating and go hungry
much of the time, but they are constantly thinking about food. When they give in, they become disinhibited and eat to excess…the “I‟ve
already blown it” problem.
– (a) Percentage of adults of normal weight in 1994-95 who became
overweight by 2002-03. (b) Percentage of overweight adults in 1994-95
who became obese by 2003-03. Source: Le Petit & Berthelot (2005).
– Fig 10.6 – The heritability of weight. Body mass index is a measure of
weight that controls for variations in height. Twin studies reveal that
identical twins are much more similar in body mass index than fraternal twins, suggesting that genetic factors account for much of the variation
among people in the propensity to become overweight. (Data from
Stunkard et al., 1990)
– Human Sexual Response
– Sexual Motivation and Behaviour: Determining Desire
Parental Investment Theory (Trivers, 1972)
Drive and Cognition
Erotic materials: The Porn Debate
Featured Study p. 458
Hormones exert considerable influence on sexual behaviour in many
animals, but human sexuality is influenced by much more than hormones.
Research suggests that hormones do have at least a small role in human
sexual behaviour, as testosterone fluctuations are correlated with sexual
A pheromone is a chemical secreted by one animal that affects the
behaviour of another, usually detected through the sense of smell.
Research on pheromones in humans is inconclusive with regard to sexual desire; however, they have been linked to synchronized ovulation among
women who live together.
Aphrodisiacs are substances thought to increase sexual desire. Research
shows that oysters, vitamin E, etc., have no real impact on sexual desire.
Pharmaceutical companies are, however, working on developing
aphrodisiacs, and there are promising leads. Viagra is not a sexual
stimulant, improving performance, not desire.
Erotic materials have been shown to elevate sexual desire only for a few
hours, but they may have an enduring effect on attitudes about sex.
Aggressive pornography may make sexual coercion seem less offensive
and may contribute to date rape.
Attraction to a partner is a critical determinant of sexual interest. The
phenomenon of a new sexual partner reviving sexual interest is termed
the Coolidge effect.
Evolutionary factors in human sexual behaviour are theorized to hinge on
parental investment, with females being more discriminating in choosing
partners and less likely to engage in casual sex. This has been used to
explain sex differences such as males thinking about sex more frequently,
males emphasizing youthfulness and attractiveness in a potential partner,
and females emphasizing status and financial prospects in a potential
– Fig 10.9 – Parental investment theory and mating preferences. Parental
investment theory suggests that basic differences between males and
females in parental investment have great adaptive significance and lead
to gender differences in mating propensities and preferences, as outlined
– Fig 10.10 – The gender gap in how much people think about sex.
This graph summarizes data on how often males and females think about
sex, based on a large-scale survey by Laumann, et al., (1994). As
evolutionary theorists would predict, based on parental investment
theory, males seem to manifest more interest in sexual activity than their
– Fig 10.12 – Gender and potential mates’ financial prospects.
Consistent with evolutionary theory, Buss (1989) found that females
place more emphasis on potential partners’ financial prospects than males
do. Moreover, he found that this trend transcended culture. The specific
results for 6 of the 37 cultures studied by Buss are shown here.
– Fig 10.13 – Gender and potential mates’ physical attractiveness.
Consistent with evolutionary theory, Buss (1989) found that all over the
world, males place more emphasis on potential partners’ good looks than
do females. The specific results for 6 of the 37 cultures studied by Buss
are shown here.
– The Mystery of Sexual Orientation
Heterosexual – Bisexual – Homosexual
Theories explaining homosexuality
Sexual orientation refers to a person‟s preference for emotional and
sexual relationships with individuals of the same sex (homosexuality), the
other sex (heterosexuality), or either sex (bisexuality).
Recent conceptualizations of sexuality hold that homosexuality and
heterosexuality are endpoints on a continuum.
Data on the prevalence of homosexuality suggests that 5-8% of the
population may have a homosexual orientation.
Many environmental theories explaining homosexuality have been put
forth historically. Freud held that a person must identify with the same
sexed parent, or homosexuality results. behaviourists assert that
homosexuality is learned through conditioning. Research has failed to
support either theory. What has been found is that most men and women
with homosexual orientations can trace their leanings back to early
childhood, suggesting a biological basis.
Biological research suggests that there is a genetic predisposition to
homosexuality, possibly based on the X chromosome. Anatomical
differences between gay and straight men in the size of the anterior
hypothalamus have also been found. This structure is larger in men than
in women, and this study showed that gay men had a 50% smaller AH
than straight men.
Some theorists believe that anatomical brain differences such as these
may be due to the organizing effects of prenatal hormones on
The interactionist view holds that genes and prenatal hormones shape a
child‟s temperament, which initiates a chain of events that ultimately
shapes sexual orientation.
– Fig 10.15 – Homosexuality and heterosexuality as endpoints on a
continuum. Sex researchers view heterosexuality and homosexuality as
falling on a continuum rather than make an all-or-none distinction. Kinsey
and his associates (1948, 1953) created this seven-point scale (from 0 to
6) to describe people’s sexual orientation. They used the term ambisexual
to describe those who fall in the middle of the scale, but such people are
commonly called bisexual today.
– Fig 10.16 – How common is homosexuality? The answer to this
question is both complex and controversial. Michaels (1996) brought
together data from two large-scale surveys to arrive at the estimates
shown here. If you look at how many people have actually had a same-
sex partner in the last five years, the figures are relatively low, but if you
count those who have had a same-sex partner since puberty the figures
more than double. Still another approach is to ask people whether they
are attracted to others of the same sex (regardless of their actual
behaviour). This approach suggests that about 8% of the population
could be characterized as homosexual.
– Fig 10.17 – Genetics and sexual orientation. A concordance rate
indicates the percentage of twin pairs or other pairs of relatives who
exhibit the same characteristic. If relatives who share more genetic
relatedness show higher concordance rates than relatives who share less
genetic overlap, this evidence suggests a genetic predisposition to the
characteristic. Recent studies of both gay men and lesbian women have
found higher concordance rates among identical twins than fraternal
twins, who, in turn, exhibit more concordance than adoptive siblings.
These findings are consistent with the hypothesis that genetic factors
influence sexual orientation. (Data from Bailey & Pillard,
– 1991; Bailey et al., 1993)
– Affiliation and Achievement Motivation
Affiliation motive = need for social bonds
Devote more time to interpersonal activities
Worry more about acceptance
Achievement motive = need to excel
Work harder and more persistently Delay gratification
Pursue competitive careers
Situational influences on achievement motives
Thematic Apperception Test (TAT)
Affiliation motivation is the need to associate with others and to maintain
social bonds. People who are relatively high in affiliation motivation tend
to devote more time to interpersonal activities and to worry more about
acceptance than others do.
Achievement motivation involves the need to excel, especially in
competition with others.
People who are relatively high in the need for achievement work harder
and more persistently, they tend to delay gratification well and to pursue
Both affiliation and achievement motivation are generally measured using
the TAT, a projective test which requires a subject to write or tell stories
about what is happening in pictures of people in ambiguous scenes.
Situational factors have been shown to influence achievement motivation,
causing it to increase when the probability of success and the incentive
value of success are high. Additionally, the pursuit of achievement can
be influenced by a fear of failure, so that the motive to avoid failure
– – Fig 10.19 – Determinants of achievement behaviour. According to
John Atkinson, a person’s pursuit of achievement in a particular situation
depends on several factors. Some of these factors, such as need for
achievement or fear of failure, are relatively stable motives that are part
of the person’s personality. Many other factors, such as the likelihood and
value of success or failure, vary from one situation to another, depending
on the circumstances.
– The Elements of Emotional Experience
Subjective conscious experience
Bodily (autonomic) arousal
Characteristic overt expressions
The cognitive component of emotion involves subjective feelings that
have an evaluative aspect…a cognitive appraisal of an event is an
important element in emotional experience. Researchers have, in the
past, focused primarily on negative emotions, consistent with the bias in
the field of psychology toward studying pathology, weakness, and
suffering. In recent years, however, a group of psychologists have
advocated for positive psychology…increasing research on contentment,
well-being, human strength, and positive emotion.
The physiological arousal associated with emotion occurs through the
actions of the autonomic nervous system. The autonomic nervous system
is responsible for the highly emotional fight-or-flight response. The
galvanic skin response (GSR) measures autonomic activation – the device
that measures autonomic fluctuations while a person is questioned is
called a polygraph or lie detector (really an emotion detector). Polygraph
tests measure emotion, which may or may not be due to deceit; they are
inaccurate often enough that they are deemed not reliable enough to be
submitted as evidence in most types of courtrooms. In the brain, the limbic system is the emotional circuit (the
hypothalamus, the amygdala, and adjacent structures); Joseph LeDoux
(1996) has shown that the amygdala plays a particularly central role in
behaviourally, emotions are expressed through body language and facial
expressions. Research indicates considerable cross-cultural similarities in
the ability to differentiate facial expressions of emotion. The facial-
feedback hypothesis holds that facial muscles send signals to the brain
that help it recognize the emotion being experienced…smile and feel
Cross-cultural similarities have also been found in the cognitive and
behavioural components, although display rules, or norms for regulating
appropriate expression of emotion, vary from culture to culture.
– – Fig 10.22 – The amygdala and fear. Emotions are controlled by a
constellation of interacting brain systems, but the amygdala appears to
play a particularly crucial role. According to LeDoux (1996), sensory
inputs that can trigger fear arrive in the thalamus and then are routed
along a fast pathway (shown in red) directly to the amygdala, and along a
slow pathway (shown in green) that allows the cortex time to think about
the situation. Activity in the fast pathway allows for rapid responses to
threats, which has probably had
– adaptive significance for humans. Activity in this pathway also quickly
elicits the autonomic
– arousal and hormonal responses that are part of the physiological
component of emotion.
– Cross-cultural comparisons of people’s ability to recognize
emotions from facial expressions. Ekman and Friesen (1975) found
that people in highly disparate cultures showed fair agreement on the
emotions portrayed in these photos. This consensus across cultures
suggests that facial expressions of emotions may have a biological basis.
– Theories of Emotion
Feel afraid because pulse is racing Cannon-Bard
Thalamus sends signals simultaneously to the cortex and the
autonomic nervous system
Schacter’s Two-Factor Theory
Look to external cues to decide what to feel
Innate reactions with little cognitive interpretation
The James-Lange theory of emotion holds that you see a snake, your
pulse races, and you feel afraid because your pulse is racing.
The Cannon-Bard the