Intelligence & Reasoning

Your Implicit Theories of Intelligence

Intelligent Unintelligent

1986 Expert Definitions

Adaptation to environmentBasic mental processesReasoning, problem solving, decision

makingMetacognition –

Intelligence

Consider Albert Einstein (1879 - 1955)

German-born U.S. physicisttheory of general relativity exploitation of atomic energy

won a Nobel prize in 1921"einsteinium" named after

Einstein

How intelligent was Einstein?Estimated IQ = 160

Can you think of others thought to be intelligent?

And why?

What is IQ? An estimate of intellectual ability

Wechsler - "capacity of the individual to act purposefully, to think rationally, and to deal effectively with [the] environment“

True IQ can not be known

It’s a quantification of a concept…

…except it’s an often misunderstood and misused concept

History of Intelligence Testing

Sir Francis Galton (1822-1911) Cousin of Darwin English Intellectual Correlation coefficient Eugenics – forbidding certain

individuals to bear children, etc. Pioneer in Intelligence Invented first comprehensive test of

intelligence (Adults)

Galton cont’d

Two general qualities distinguished individuals who were more intelligent from those less intelligent

1. Energy = speed or neural quickness

2. Sensitivity = sensory acuity or accuracy Had people close their eyes and put objects that looked

and felt the same in order based on weight. Similar for touch: wires of differing fineness, taste = salt, hearing = pitch, smell = different amounts of perfume.

Intelligence is _______________________

Alfred Binet (1857-1911)

Found that Galton's tasks did not discriminate between children and adults

His work represented the beginning of modern intellectual testing.

History of the Study of Intelligence

Binet and Simon (early 1900s) Higher-Order Mental Abilities Central to Intelligence

1. Direction: knowing what has to be done and how it is accomplished.

2. Adaptation: task selection and monitoring.

3. Control: Ability to criticize one’s thoughts and actions: If you notice the sum is smaller than one of the numbers you realise you have to do it again.

History of the Study of Intelligence

Binet and Simon (early 1900s)

All forms of making judgments, decision-making, strategizing = executive functioning

Believed intelligence could be improved through instruction and practice

General Intelligence

Charles Spearman’s Psychometric Model (1904) Developed a new set of tests and the statistical

technique “factor analysis” to make sense of the results. It finds patterns of correlations among scores or measures of identify sets of underlying abilities.

FA finds patterns of correlations among scores Identified two separate factors influencing

performance on intelligence tests: g = general intelligences = specific ability

Spearman’s Psychometric Model

g = general intelligenceUsed to explain why most intelligence tests

correlated with each other (ranging from 0.30 to 0.60)

Some common denominator = biologically based s = specific ability

Used to explain why correlations were not perfectLearned ability

Score is a combination of both g and s

Two Kinds of g (general intelligence)

Raymond Cattell (1971) – worked with Spearman and later modified Spearman’s theory to include two kinds of g:

Fluid Intelligence Reason abstractly and think flexibly Perceive relationships or differences Peaks between 20-25 years of age and then

declines Crystallized Intelligence

Derived from previous experience Accumulated knowledge (words, cultural practices) Increases until age 50

Modern Intelligence Tests

Stanford-Binet Intelligence TestDeveloped by Lewis Terman at Stanford in 1916Influenced by Binet & Simon

Grounded in competencies central to schoolingIdentify body parts of a dollSimilarities and differences (how are a dog and a

cat similar? different?)Arithmetic word problems

Binet-based tests, cont’d

Intelligence Quotient (IQ)

Mental Age = match the individual’s test score to the age group whose average score was similar

e.g., Mental Age = 10 any child whose score was similar to an average 10-year-old

Mental age/actual (chronological) age x 100 = IQ E.g., 10/10 = 1 x 100 = 100 E.g., 10/8 = 1.25 x 100 = 125 An IQ of 100 is average for your age group This concept of IQ is not bad for children, but…Absurd to say

that a 20 year old who performs as well as a 60 year old has an IQ of 300.

Wechsler Scales Developed by David Wechsler in 1930s Kept term “IQ” but adapted the meaning to compare

performance to the average person.Verbal subtests: vocabulary, similarities,

information, comprehension, digit span, letter-number sequencing, arithmetic

Performance subtests: block design, picture completion, picture arrangement, object assembly, matrix reasoning, digit-symbol coding, symbol search

Wechsler Scales

Standardized Scoring:compare your score to those from a

large sample of individuals of the same age

Mean = 100Standard deviation = 15 We’ll see more on this later

WISC-III = ___________

David Weschler

Wechsler’s Innovations…

a. based the scoring scheme on the normal distribution - discarded the idea of IQ based on mental age

b. involve verbal and performance scales

c. relied less on verbal ability than previous measures of intelligence

WAIS

Full Scale IQVerbal IQPerformance IQ

WAIS-III Verbal Subtests

Information: what is the capital of France?

Comprehension: what should you do if you find a wallet on the street?

Arithmetic: If you have 4 apples and eat 3 how many are left?

Similarities: How are dog and cat alike?

Vocabulary: define chair, asylum,etc

Digit span: repeat number sequences in forward and reverse

order Letter-Number sequencing:

Repeat list of letters and numbers in chronological order

WAIS-III Performance Subtests

Digit symbol: copy designs associated with different numbers

Picture completion:determine what is missing from a picture

Block design: arrange blocks to match a picture

Picture arrangement: arrange pictures so they tell a story

Object assembly:put a puzzle together

Matrix Reasoning: Determine what goes next in a pattern

Symbol Search: Determine if the target symbols match any of

the symbols in the search group

WAIS and Binet Tests

are individual tests

usually administered on an one to one basis

Two pitfalls:

expensive to administer

time consuming to administer

Common Uses - Past

Binet - detection of mental deficiencies or giftedness in children and mentaldeficiencies in adults

Terman-______________________

Wechsler- assess learning disabilities and neuropsychological evaluation

More on INTELLIGENCE to come later:

but for now, let’s look at tests

in general

Measures of psychological constructs: applications and strategies

What’s a psychological test?Assesses of a sample of behaviour. Interpret it

cautiously (do we know the test is valid? Can we infer from the sample to day-to-day reality?).

• Best to use more than one test (increases reliability + trust in the result).

Ex: Applying to Grad School

graduate school criteria: GRE scores, references letters, statement of purpose, experience, publications, marks and personal interviews. Participation in an Honours program also important for Psychology.

Looking for more than high grades.

when assessing some psychological construct, use... 1. 2.

Assessing the person…

Person

Recommendation

Grades

Publications

GRE

Letter ofIntent

The higher the better

Know refereesWell…

Rare for students

HigherThe Better

MagicNumber1800 (top score 2400)

Is it clear? Do they know what they want, and want to research?

Categories of other Psychological Tests

Personality

Mental Abilities

Others?

Personality Tests

Objective: Projective

Thematic Apperception Test – personality said to be revealed depending on stories told about pictures of ambiguous scenes.

Minnesota Multiphasic Personality Inventory. Multiple scales with multiple items.

Mental Abilities Tests

Mental ability tests

1) Intelligence test

2) Aptitude

3) Achievement tests

Mental Abilities Tests

intelligence tests are intended to measure general mental ability

aptitude tests are intended to measure specific types of mental abilities: _________________________?

achievement tests are intended to gauge a person's mastery and knowledge of various subjects: _______

What Makes a Test Good?

A Test Must Be:Reliable Valid

Reliable = consistentValid = measuring what it

is suppose to measure

Reliability and Validity

Target Practice …!

Reliability and ValidityReliable but not validReliable but not validReliable but not validReliable but not valid

Reliability and ValidityNeither reliable nor validNeither reliable nor validNeither reliable nor validNeither reliable nor valid

Reliability and ValidityReliable and validReliable and validReliable and validReliable and valid

Definition of Reliability

reliability = refers to test's precision, dependability, consistency

A reliable test minimizes error and provides repeatable consistent results.

Classical Test TheoryClassical Test Theory

ObservedObservedscorescore

ObservedObservedscorescore ==

TrueTrueabilityabilityTrueTrue

abilityability++ RandomRandom

errorerrorRandomRandom

errorerror

Classical Test Theory

Suppose my true weight is 140 lbs Suppose my scale is cheap (unreliable)

Assessed Weight X = 135, 143, 141, 144

E = -5, 3, 1, 4

Types of Reliability

• Test-retest• Alternate Forms• Internal Consistency• Inter-rater

(1) Test-Retest Reliability

Administering the same test to the same set of examinees on two separate occasions.

Test-Retest Reliability

Questionnaire (Completed 9/20)

___ I feel I do not have much proud of.

___ On the whole, I am satisfied with myself

___ I certainly feel useless at times

___ At times I think I am no good at all

___ I have a number of good qualities

___ I am able to do things as well as others

Questionnaire (Completed 9/27)

___ I feel I do not have much proud of.

___ On the whole, I am satisfied with myself

___ I certainly feel useless at times

___ At times I think I am no good at all

___ I have a number of good qualities

___ I am able to do things as well as others

432143

441144

(2) Alternate Forms

Two versions of the same test with similar content.

Forms must be equal

(3) SPLIT HALF

Measures internal consistency.

Correlate two halves such as odd versus even items.

Works only for tests with homogeneous content

Odd

Even

(4) Interrater Reliability

Measures scorer or inter-rater reliability

Do different judges agree?

Cronbach’s alpha – commonly used for assessing psychological tests. How well do the items hang together? Does someone who ranks one question as a “5” rank most other questions as “5,” for instance?Example on next slide:

Is this a good measure of sleep quality?

1 = Completely disagree, 5 = Completely agree I had a good sleep last night. I tossed and turned last night. My life is full of stress. I woke up this morning feel refreshed. I feel awake enough to accomplish

today’s tasks. My bed is very comfy.

Validity

The ability of a test to measure what it is supposed to measure.

Types of Validity

Face Content Criterion Construct Factorial

Types of Validity:Face Validity

Concerns mere

appearance of

test –

Types of Validity: Content

Content - the degree to which the content of a test is representative of the domain it's supposed to cover. Is it covering all aspects of the construct in

question? (sleep quality, intelligence, etc.)

Types of Validity: Criterion

Most important form of validity: criterion. Criterion validity: is estimated by correlating

subjects' scores on a test with their scores on an independent criterion

In other words: accuracy with which test scores can be used to predict another variable of interest (the criterion). For example:

Types of Validity: Construct Construct – The extent to which a measurement

method accurately represents a construct and produces an observation distinct from that produced by a measure of another construct.

In other words: The degree to which inferences can legitimately be made from the “working definitions” in your study to the theoretical constructs on which those definitions were based.

Construct validity cont’d

Construct validity involves generalizing from your program or measures to the concept of your program or measures. You might think of construct validity as a "labeling" issue. When you measure what you term "self esteem" is that what you were really measuring?

Your “self esteem” scale might be measuring some construct, but is it actually self esteem, or might it be that you are actually assessing another construct such as optimism or confidence?

Back to our discussion of intelligence…

Deviation IQ Scores

the intelligence quotient developed by Terman has now been replaced by the deviation IQ

deviation IQ = scores that locate subjects precisely within the normal distribution, using standard deviation as the unit of measurement

average deviation IQ is set at 100 standard deviation of 15 a score of 100 lies at the 50th percentile

Deviation IQ Scores

based on deviation IQ scores, there are a variety of mental classifications

these categories are arbitrary

55 to 70 = retarded70 to 85 = borderline85 to 115 = average 115 to 130 = superior130 to 145 = gifted

Does school make you smarter?

Emerging evidence that education influences intelligence. However, effect may be due to students self-selecting for college & university (more able students may stay in school longer, thus confounding results).

Research that is able to rule out other influences indicates that education_____________________

Extremes of Intelligence

mental retardation (MR) and giftedness

MR = subnormal mental ability accompanied by deficiencies in everyday living skills

Less than two standard deviations below a mean of 100.

the cutoff point is...

Mental Retardation

85% of persons classified as mentally retarded have a score between_____

which means they have about a grade 6 level of functioning and often can be self-supporting

Causes of Mental Retardation

organic causes such as Down syndrome, hydrocephaly (“water on the brain”)

organic causes only account for 25% of the known cases

cause is not known in 75% of the cases

Retarded Savants Severe mental handicaps

But retarded savants have spectacular islands of ability or brilliance.

Some have skills that are remarkable in contrast to the handicap; others have an ability that would be spectacular even in a non-retarded individual.

6x more common in males than in femalesOccurs for a very narrow range of skills: calendar

calculating, music (piano almost exclusively), mathematical calculations, mechanical ability, prodigious memory, or, rarely, unusual sensory discrimination abilities (smell or touch).

How? One theory:

Underlying all savant abilities is a seemingly limitless memory. Savant art, for example, is remarkable not for its creativity but for its realism – exact copies of animals or people or scenes done from memory.

Savants do not have distractions; the brain is dedicated entirely to the task at hand. The rest of us get distracted – nine times seven, carry the two, how did that stain get on my shirt, and four sevens is…

Giftedness

Book of World Records: 4 year old Korean boy with IQ over 200.

Many of us think of the gifted child as weak, socially inept and emotionally troubled.

Terman (1921): gifted individuals tend to be physically superior, emotionally adjusted and socially mature.

Giftedness

Renzulli (1986) giftedness may be the result of three things:

exceptional intelligence in a specific domain, task-motivation, and creativity i.e. “brains” aren’t enough – the person must be creative and wish to put their intelligence to use, too.

 

IQ tests reliable and valid?

Exceptionally reliable But are intelligence tests valid? Do they measure what they are supposed to measure?

yes, intelligence tests usually measure one facet of intelligence

the correlation between academic achievement and IQ is .5 to .6the correlation between number of years of school and IQ is around .7. What other factors affect school performance?

IQ tests are reasonably valid indexes of school-related intellectual achievement

Layperson’s Conception

The limited ability of intelligence tests to tap the full range of intellect is captured by the average person's conception of IQ

the average person believes that IQ consists of verbal, practical and social intelligence. IQ tests generally fail to assess all of these factors, although they certainly assess verbal abilities and many analytical skills.

Influence of Environment individuals raised in impoverished environments tend to be

lower in IQ . This is known as the cumulative deprivation hypothesis.

parents who run an orderly household, are warm, affectionate and highly involved with their children tend to have children with higher IQ scores.

Homes that encourage exploration, experimentation and independence also foster IQ scores.

 

Providing age appropriate toys and speaking articulately to their children

 

Encouraging hard work and rewarding your children when they do well is also quite important

Reaction Range

Are there upper limits to one’s intellectual potential?

Sandra Scarr has suggested that genetics or heritability imposes limits on IQ scores - this is known as the reaction range

We will discuss this topic again at the end of the chapter when we take a closer look at heritability.

within this range, the quality of one's environment determines where one will sit along this range

This may explain certain differences among cultural groups.

The implication of this theory suggests that so-called racial differences are actually due to ______________________

Cultural Bias?

Another reason for so called racial differences is related to cultural bias.

IQ tests are slanted in favor of white middle class Americans at the expense of lower-class minorities. The tests ask questions that depend on having access to certain ideas and opportunities.

Cultural Slant?

These days the slant on IQ tests is modest

IQ differences are more likely to be the result of impoverished environment than test bias.

many school districts are shifting away from IQ tests to achievement and aptitude tests

more of an emphasis toward specific abilities

Attacks on IQ Construct

Flynn IQ tests merely measure abstract problem

solving ability, not intelligence

LezacGlobal IQs are impure and meaningless

IQ doesn't predict success in life. IQ tests are misused

IQ Tests Do Not Measure…

Other Conceptions of Intelligence

HornTwo Factor Theory

SternbergTriarchic Theory

GardnerMultiple Intelligences

Goleman EQ

Horn

Two Factor Theory of Intelligence: Fluid Intelligence - non-verbal, relatively culture

free, independent of specific instruction (i.e. memory of digits).

Crystallized Intelligence - acquired skills and knowledge that are dependent on exposure to a culture as well as to formal and informal education (i.e. vocabulary).

Robert Sternberg

Triarchic TheoryAnalyticalCreativePractical

Sternberg’s Triarchic Theory of Intelligence:

1) Componential intelligence (mental abilities most closely related to success on traditional IQ and achievement tests => analytical ability).

2) Experiential Intelligence (creative thinking and problem solving => creative ability).

3) Contextual Intelligence (practical intelligence or “street smarts” => practical ability).

Howard GardnerMultiple Intelligences

To Gardner (1985, 1993), an intelligence is any skill universal to humans and that is organised through a system of mental symbols and rules for manipulating or structuring them.

Postulates distinct brain mechanisms underlying each intelligence, which is why brain injury or developmental disorders can affect intelligences differently.

Gardner has identified what he thinks are seven distinct intelligences: linguistic, logical-mathematical, spatial , musical, bodily-kinesthetic, interpersonal, intrapersonal.

Three of his intelligences are measured by standard IQ tests (linguistic, logical-mathematical, and spatial). The others are not usually considered as part of intelligence.

Some say Gardner has stretched the definition of intelligence too far. The non-standard aspects of intelligence that he describes are called talents by others. [is this all just semantics?]

Part of his message is that some abilities are overly valued at the expense of other abilities.

There is little statistical or other objective evidence for his seven separate intelligences, however.

Emotional Intelligence: Goleman

(1) awareness of and ability to manage one’s emotions

(2) the ability to motivate oneself (3) empathy (4) the ability to handle relationships successfully

IQ Stability?

generally stable by age 7 or 8 but not set in stone -- in some people there can be substantial changes

how could these changes take place? ... knowledge of words, brain damage, what else?

Nature or Nurture?

Nature: biological inheritance, genes Nurture: environmental conditions Both are essential for any trait to develop Are differences in intelligence among

individuals due more to differences in their genes or environments?

Controversial Topic

Galton emphasized heritability (influence of genetics versus environmental influences)

typical estimates of heritability and intelligence lie to

between: 50 & 70%

consensus for intelligence hovers around 60% contribution from genetics (others argue more or less)

 

Review

When genetics or another reason puts a limit on possible IQ, what is this called? Reaction Range

What American test was created to demonstrate cultural bias? Chitling Test

Who argued that IQ tests are impure and meaningless? Lezac

Let’s examine HERITABILITY

Do you think the differences among this class group in extroversion are due mainly to differences in the environments in which you grew up, or do you think they are due mainly to differences in your genes?

Hereditability: degree to which variation in a particular trait, within a particular group of individuals ____________________________In other words, heritability is the proportion of

variance that’s caused by genetic differences among individuals within groups.

Heritability

Heritability = __________variance due to genes___________

variance from genes + variance from environment

(i.e. genetic variance / total variance)

Heritability applies to GROUPS, not to individuals.

Heritability cont’d Suppose you were all adoptive siblings, all raised in

the same home by the same parents. Do you think the differences among you in extroversion would be due more to genes or more to environment?Assuming being raised in the same home reduces

the environmental contribution to typical variability, the remaining variability will be due more to genes.

Suppose all of you were genetic clones. Now would the differences be due more to genetics or to environment? In this case, all differences must be due to

environment, and heritability = __________

Thus, heritability for any given multiply-influenced trait can be high or low depending on the degree to which members of a population differ in the relevant genes or in relevant aspects of environments.

Differences among people can be accounted for in part by the genetic differences among them. Heritability is a measure of how big that part is.

An increase in the genetic diversity of a group increases the “heritability coefficient.”

An increase in the environmental diversity of a group decreases the heritability coefficient.

Heritability cont’d

Results from Twin Studies IQs of identical twins correlate more strongly than

IQs of fraternal twins Gap widens in adulthood Studies suggest that genetic differences account for

about ½ IQ variance in children and adolescents and more among adults

In childhood environment – home/school – choices are constrained and thus contribute more to IQ. The environment constrains genetics.

In adulthood, environments are chosen based on genetics. Genetics constrain the environment.

Role of Culture

Most heritability studies conducted with white, North American and European , upper middle-class samples

Because theses samples are more uniform (participants are more similar) than representative samples of the entire population, heritability is high

When more environmental variation is introduced, heritability will decrease

Cultural Origin of IQ Differences

John Ogbu Studied Black-White differences in US,

Buraku-Ippan and Korean-Ippan differences in Japan

Minority groups, on average, typically score lower on IQ tests than majority culture

Due to caste status: membership is determined at birth, unlike social class, which is acquired after birth and can change throughout life

Involuntary minorities Showed that when Buraku-Japanese children

moved to the U.S., they performed as well as Ippan-Japanese children living in Japan and in the U.S.

Same for Korean children in U.S. compared to Korean children living in Japan

Social designation, not biology, that contributes to group differences

Problem Solving

PSYCO 105

Inductive Reasoning

Infer a new principle or proposition from a set of observations of facts

Hypothesis construction Educated guess But: biases exist in people’s strategies

Biases lead to incorrect inferences

Representativeness

The text describes how we judge the likelihood of things in terms of how well they seem to represent or match a particular prototype.

Linda is a 31, single, outspoken, and very bright. She majored in philosophy in university. As a student, she was deeply concerned with discrimination and other social issues, and she participated in antinuclear demonstrations. Which statement is more likely:

Representativeness

While representativeness works well most of the time, it leads to errors when its conclusions run counter to the laws of chance.

Information that seems typical or representative is often ______________________________

If a test to detect a disease whose prevalence is 1 in 1000 has a false positive rate of 5% (i.e. the percentage of times the test mistakenly indicates the disease is present), what are the chances that a person found to have a positive result actually has the disease, assuming you know nothing else about the person?

Base-Rate Fallacy

The base-rate fallacy is the tendency to ignore or underuse base-rate information and instead to be influenced by the distinctive features of the case being judged.

Ward Casscells and his colleagues gave this problem to physicals and med students at four Harvard Medical School teaching hospitals. They obtained an average response of _____________________________

The correct answer is about _______________

The base rate indicates that the majority of people do not have the disease, and the vast majority of positive tests come from people who do not have the disease.

Which of the following are the more frequent causes of death in the United States?

Which country has the larger population?

Availability Bias

_________________________________________

Fischoff et al. (1977) report that the more ___________ cause of death is actually more prevalent. However, _____

___________________________________________ Similarly, Brown & Siegler (1993) report that less familiar

countries have ________________________________

Other examples? Most ppl fear flying > driving

Plane crashes more vivid and memorable Flying actually much safer – ppl know this and still

feel fear

Jaws: swimmers fear sharks now No factual data to support this (It’s a risk, but typically a small one).

When thinking of buying a new car, whose testimony is more persuasive – that of a friend who has had problems that a particular model, or that of Consumer Reports, which on the basis of dozens or more reports recommends the car?

Do the media sometimes lead us to have a distorted view of the frequency of certain

events by overexposing us to some events and underexposing us to others?

The FBI classifies crime in the U.S. into two categories – violent crimes (murder, rape, robbery, assault, etc.) and property crimes (burglary, car theft, etc.). What percentage of crimes would you estimate are

violent rather than property crimes? What percentage of accused felons plead insanity? What percentage of those pleading insanity are

acquitted? What percentage of convictions for felony crimes are

obtained through trial instead of plea bargaining?

Ranking Countries by Population

Dr. Norman Brown and colleagues (2002) have continued to examine this issue.

Participants were primed with selected country names then asked to estimate populations of 109 countries __________

Chinese – Canadian comparisons:Chinese students estimated larger

populations for Asian countriesNon-Chinese Canadian students

estimated larger populations for European countries

Populations for countries equally familiar and unfamiliar were estimated similarly

Imagine 4 cards

Card 1: Black circle (black triangle on the back)Card 2: Red circle (black triangle on the other side)Card 3: Red triangle (black circle on the other side)Card 4: Black triangle (red circle on the other side)

Assuming each card has a triangle on one side and a circle on the other, which card or cards need to be turned over to TEST THIS STATEMENT: “Every card that has a black triangle on one side has a red circle on the other’”

Card 1: Black circle (black triangle on the back)Card 2: Red circle (black triangle on the other side)Card 3: Red triangle (black circle on the other side)Card 4: Black triangle (red circle on the other side)

Confirmation Bias ______________________________ Leads to errors

Can have implications for our social judgments. Eldar Shafir (1993) presented research participants with the following scenario:

Imagine that you serve on the jury of an only-child sole custody case following a relatively messy divorce. The facts of the case are complicated by ambiguous economic, social, and emotional considerations, and you decide to base your decision solely on the following few observations. To which parent would you award sole custody of the child?

Parent A, who has an average income, average health, average working hours, a reasonable rapport with the child, and a relatively stable social life. OR

Parent B, who has an above-average income, minor health problems, lots of work-related travel, a very close relationship with the child, and an extremely active social life.

Here’s the twist:

½ were asked to choose which parent to AWARD custody to and the other ½ to choose which parent to DENY custody:

Confirmation Bias

David Levy’s (1997) Tools of Critical Thinking devotes a number of chapters to common cognitive biases like this.

We often employ strategies for eliciting information from others that supports our initial beliefs about them. For example, in one study college students were instructed to conduct interviews with other students to assess the presence of certain personality traits. Half were asked to determine if the person was an extrovert and have asked to determine if the person was an introvert.

The interviewers asked extrovert-related questions when they wanted to see if someone was an extrovert. Ex: What would you do if you wanted to liven up a party?

They asked introvert-related questions to decide if the person was an introvert. Ex: What factors make it really hard for you to open up to people?

As you can imagine, ____________________

Tree-Planting Problem

You have 10 trees to plant on a large, flat area of your rural Alberta farm. They must be planted in a pattern so that the ten trees form

Mental Sets

Well established habits of perception or thought patterns

Tree-Planting Problem:

Solving problems and using insight provides a sense of satisfaction. The solution to a riddle of the joy of a joke may come in our sudden comprehension of an unexpected ending or double meaning.

Consider the game Mindtrap (Great American Puzzle Factory, Inc.), which includes the following teasers:

What number is next in this series: 10, 4, 5, 11, 15…?

Aside from the fact that it doesn’t make much sense, what is so unusual about this sentence: