What is Intelligence? Definition: 3 main characteristics 1) 2) 3)

Brief History of Intelligence Testing

Alfred Binet

Lewis Terman (Mental Age) (Chronological Age) X 100 = IQ (Intelligence Quotient)

The Normal Curve and Stanford-Binet IQ Scores IQs less than 70 = Intellectually Disabled. More than 130 = gifted Fig. 8.1

Problems with the IQ Formula

David Wechsler

Intelligence Tests Today Updated versions of Stanford-Binet and Wechsler tests are most commonly used intelligence tests today IQ score no longer determined by dividing mental age by chronological age Now compare total score to others at age level Average score = 100 Other scores based on amount of deviation from average “normal curve” Score reflects relative standing within population of your age

Psychological Test Concepts

Types of Psychological Tests Intelligence Tests Aptitude Tests A test designed to measure a person’s capacity to learn certain things or perform certain tasks SAT, ACT, and GRE (verbal and quantitative components), Wonderlic Look to measure “potential” Achievement Tests A measure of what a person has accomplished or learned in a particular area MCA tests, AP Psychology Exam Personality Tests

Aptitude v. Achievement Tests

How do we construct Intelligence tests? Tests must be:

Standardization The test must be pre-tested to a representative sample of people and Form a normal distribution or bell curve

Determining Test Quality Standardizing Conditions surrounding a test are as similar as possible for everyone who takes it Helps eliminate possible bias of those giving or scoring the test – objective Norms Description of frequency at which particular scores occur, allowing scores to be compared statistically Standardization group Representative sample of people pretested to determine meaningful scores Percentile score Percent of individuals in normative group whom the individual has scored above

Reliability Spilt halves or test–retest method.

Reliability The degree to which a test can be repeated with the same results “Test-Retest Reliability” A group of people take the same test twice “Alternate Form Reliability” Different, but similar test on 2nd trial – reduce practice effects “Split-half” method Correlation is calculated b/w person’s scores on two comparable halves of test (“Internal Consistency Reliability”) Inter-Rater reliability Determine degree to which different raters/observers give consistent estimates of same phenomenon

Does Intelligence Change Over Time?

Validity Content Validity: does the test sample a behavior of interest Predictive Validity: does the test predict future behavior. Criterion related validity

Validity The degree to which test scores are interpreted correctly and used appropriately Content validity Content of a test is a fair, representative sample of what the test is supposed to measure Criterion-related validity (predictive validity) Correlation between test scores and an independent measure of what it is supposed to assess Construct validity Extent to which scores suggest test is measuring theoretical construct it claims to measure

Flynn Effect

The Flynn Effect Performance on IQ scores has steadily increased over generations Environmental factors?

Test Bias? Tests do discriminate. But some argue that their sole purpose is to discriminate. We have to look at the type of discrimination.

Group Differences in Intelligence Test Scores The Bell curve is different for Whites v. Black. Math scores are different across genders and the highest scores are for Asian males. Why? Nature or Nurture

Theories of Intelligence

Is intelligence one general trait or many specific abilities?

Is intelligence one general trait or many specific abilities? L.L. Thurstone

Information Processing Approach Theory that attempts to understand intelligence by examining the mental operations (i.e. attention, memory) involved in intelligent behavior

Triarchic Theory of Intelligence Robert Sternberg (Tufts University) 3 types of intelligence: Analytic: Creative: Practical:

Multiple Intelligences (MI) Theory Howard Gardner (Harvard)

Multiple Intelligences (MI) Theory Linguistic Logical-mathematical Spatial Musical Body-kinesthetic Intrapersonal Interpersonal Naturalistic Commonly measured in intelligence tests Suggests they interact, but can function with some independence Some can become more developed than others Critics suggest that many of these are better labeled as “skills” than “intelligences” Also, don’t really have dependable measures

Emotional Intelligence Daniel Goleman, Peter Salovey, John D. Mayer, & others

Is intelligence one thing or several different abilities? To find out scientists use FACTOR ANALYSIS: He saw using FA that doing well in one area of a test predicted that you will do well in another.

Multiple Intelligences Howard Gardner disagreed with Spearman’s g and instead came up with the concept of multiple intelligences. He came up with the idea by studying savants (a condition where a person has limited mental ability but is exceptional in one area).

Gardner’s Multiple Intelligences? Visual/Spatial Verbal/Linguistic Logical/Mathematical Bodily/Kinesthetic Musical/Rhythmic Interpersonal Intrapersonal Natural Learn More about Gardner

Sternberg’s Three Aspects of Intelligence Gardner Simplified Analytical (academic problem solving). Creative (generating novel ideas) Practical (common sense).

Gardner’s Three New Intelligences Naturalistic intelligence Spiritual intelligence Existential intelligence

Types & Characteristics of Tests Aptitude: person’s capability Achievement: person’s knowledge of subject Characteristics Validity: the ability of the test to measure what you say it will measure Reliability: the ability of the test to measure a construct with consistency Standardization: the use of reference scores for interpreting an individual’s performance

Types of Validity & Reliability of Tests Content: Complete range of material Criterion: Compare to other tests of the same measure (high on SAT, high on ACT) Predictive: future performance (MCAT) Construct: theoretical or hypothetical construct (depression, intelligence) Reliability Test-retest: Alternate form: Inter-rater:

Brain Size and Intelligence Is there a link? Small +.15 correlation between head size and intelligence scores (relative to body size). Using an MRI we found +.44 correlation with brain size and IQ score.