psyc 102 lec 7

Spearman's G Factor (early 1900s)

Proposed intelligence consists of a general factor "g" (most important) and specific factors "s" (s1, s2, s3, s4) unique to particular tests

G Factor – Advantages

Can be represented with an IQ score; good predictor of academic success

G Factor – Disadvantages

Neglects other types of abilities such as motor, musical, practical, and creative skills

Thurstone's Primary Mental Abilities (1938)

Analyzed 56 different mental ability tests using factor analysis and identified 7 primary mental abilities

Thurstone – Verbal Comprehension

The ability to understand and use language effectively

Thurstone – Word Fluency

The ability to generate a large number of words or ideas quickly

Thurstone – Numerical Ability

The ability to work with numbers and mathematical concepts

Thurstone – Spatial Ability

The ability to perceive and manipulate visual images and spatial relationships

Thurstone – Memory

The ability to store and retrieve information

Thurstone – Perceptual Speed

The ability to quickly and accurately perceive and identify visual stimuli

Thurstone – Inductive Reasoning

The ability to recognize patterns and make generalizations based on specific instances

Fluid Intelligence (Cattell-Horn CHC)

The ability to reason abstractly, identify patterns, form concepts, and use logic to solve novel problems, regardless of previous knowledge or experience

Crystallized Intelligence (Cattell-Horn CHC)

The use of information acquired from previous experiences, including verbal comprehension, social skills, and general knowledge

CHC Theory of Intelligence

The most scientifically supported theory of intelligence; proposes intelligence is made up of multiple abilities organized in a hierarchy from specific to broad abilities

Gardner's Multiple Intelligences (1983)

Howard Gardner's theory that intelligence is not a single unified concept but a combination of relatively independent abilities or intelligences

Gardner's Definition of Intelligence

The ability or skill to solve problems or fashion products that are valued within one or more cultural settings

Sternberg's Triarchic Theory

Criticized Spearman's g as too narrow; defined intelligence through three types of reasoning: analytic, problem solving, and practical

Binet's Definition of Intelligence

The ability to judge well, to understand well, and to reason well

Terman's Definition of Intelligence

The capacity to form concepts and grasp their significance

Wechsler's Definition of Intelligence

The aggregate or global capacity of the individual to act purposefully, think rationally, and deal effectively with the environment

Sternberg's Definition of Intelligence

The mental capacity to automatize information processing and emit contextually appropriate behaviour in response to novelty

Reliability

The extent to which a measurement tool measures something consistently; includes consistency among scores, raters, and over time

Inter-Rater Reliability

A measure of agreement between two or more raters on their ratings of performance or behaviour; computed by correlating scores or calculating percentage agreement

Test-Retest Reliability

Administering the same test to the same people at two different times and correlating the scores; only valid for traits that remain stable over time

Test-Retest Reliability – Concerns

Can be influenced by learning, memory, fatigue, motivation, and maturation effects, which may change responses over time

Split-Half Reliability

Dividing test items into two halves (e.g., odd/even), scoring each separately, and calculating the correlation; greater number of items produces greater reliability

Validity

The extent to which inferences made from a test are appropriate, meaningful, and useful; whether a test measures what it is intended to measure

Content Validity

The extent to which test items represent a fair sample of all possible questions in the domain being measured; reflects time spent teaching each topic

Concurrent Validity

How well a test correlates with an independent criterion measured at the same time; high correlation = evidence of validity

Predictive Validity

How well a test predicts future performance on a criterion (e.g., MCAT scores predicting medical school success)

Binet-Simon Intelligence Scale (1904)

Developed to identify children who would struggle in school; based on age differentiation and the concept of mental age vs. chronological age

Mental Age

The age level of tasks a person can successfully complete, regardless of their chronological age (e.g., a 7-year-old completing tasks a 10-year-old can = mental age of 10)

IQ (Intelligence Quotient)

A score that relates mental age to chronological age; adapted for use in the U.S. by Lewis Terman at Stanford University

Wechsler Adult Intelligence Scale (WAIS)

Developed in 1939 to address limitations of the Stanford-Binet for adults; produces multiple scores rather than one; designed for ages 16 to 90 years 11 months

WAIS-IV – Verbal Comprehension Scale

Measures ability to understand and use verbal information; subtests include Similarities, Vocabulary, Information, and Comprehension

WAIS-IV – Perceptual Reasoning Scale

Measures ability to reason and problem-solve using visual-spatial and nonverbal information; subtests include Block Design, Matrix Reasoning, Visual Puzzles, Picture Completion, and Figure Weights

WAIS-IV – Working Memory Scale

Measures ability to temporarily hold and manipulate information in memory; subtests include Digit Span, Arithmetic, and Letter-Number Sequencing

WAIS-IV – Processing Speed Scale

Measures ability to process simple or routine information quickly and accurately; subtests include Symbol Search, Coding, and Cancellation

Average IQ Score

100, with a standard deviation of 15; ~68% of people score between 85–115; ~95% score between 70–130; ~99% score between 55–145

The Flynn Effect

A steady increase in IQ scores over time (13.8 point increase between 1932 and 1978); greater gains found in nonverbal and performance-based measures; may be due to education, environment, or test development

IQ and Real-World Performance

IQ scores correlate with academic performance, years of schooling, occupational and social achievements, income, and health-related behaviours; correlation does not mean causation

Nature vs. Nurture in Intelligence

Identical twins correlate at .86 vs. fraternal twins at .60; heritability of IQ is ~50%; education is the most consistent means for increasing IQ; early intervention can support development in deprived environments

Brain Size and Intelligence

There may be a causal link; human brain volume has tripled over 3 million years, associated with higher intelligence

Neural Density and Intelligence

Intelligence may be higher in individuals with more neurons, particularly in the frontal lobe

Processing Speed and Intelligence

People with higher intelligence typically process information and make decisions more quickly

Neural Efficiency and Intelligence

Individuals with higher IQs show lower brain activity during low to moderate cognitive difficulty tasks

Cortical Maturation and Intelligence

Changes in cortical thickness may relate to intelligence; thicker cortexes are associated with higher intelligence