Intelligence in Historical Perspective

• Sir Francis Galton: Quantifying Mental Ability

  • Influenced by Darwin’s theory on evolution

  • He developed measures of reaction speed, hand strength, and sensory acuity

  • Even measured the size of people’s skulls, believing that skull size reflected brain volume and hence intelligence

• Alfred Binet’s Mental Tests

  • Created IQ tests, building off Galton’s theories

• Intelligence Quotient (IQ): was the ratio of mental age to chronological age, multiplied by 100: IQ = (mental age/chronological age) x 100

The Nature of Intelligence

• Fluid Intelligence: the ability to deal with novel problem-solving situations for which personal experience does not provide a solution

• Three-statum Theory of Cognitive abilities: establishes three levels of mental skills— general, broad, and narrow—arranged in a hierarchical model.

• Cognitive Process Theories: explore the specific information-processing and cognitive processes that underlie intellectual ability

• Metacompontents: addresses both the psychological processes involved in intelligent behavior and the diverse forms that intelligence can take

• Performance Components: are the higher-order processes used to plan and regulate task performance.

• Knowledge Acquisition Components: allow us to learn from our experiences, store information in memory, and combine new insights with previously acquired information

• Personal Intelligence: the ability to understand who one is and who one wants to be

The Measurement of Intelligence

• Achievement Test:  designed to find out how much they have learned so far in their lives

• Aptitude Test: containing novel puzzlelike problems that presumably go beyond prior learning and are thought to measure applicants’ potential for future learning and performance

• Psychological Test: a method for measuring individual differences related to some psychological concept, or construct, based on a sample of relevant behavior in a scientifically designed and controlled situation.

• Reliability: refers to consistency of measurement.

• Test-Retest Reliability: which is assessed by administering the measure to the same group of participants on two (or more) separate occasions and correlating the two (or more) sets of scores

• Internal Consistency: has to do with consistency of measurement within the test itself.

• Interlude Reliability:  refers to the consistency of measurement when different people observe the same event or score the same test.

• Validity:  refers to how well a test actually measures what it is designed to measure

• Construct Validity:  exists when a test successfully measures the psychological construct it is designed to measure, as indicated by relations between test scores and other behaviors that it should be related to

• Content Validity: refers to whether the items on a test measure all the knowledge or skills that are assumed to underlie the construct of interest

• Criterion-related Validity:  refers to the ability of test scores to correlate with meaningful criterion measures.

• Standardization: has two meanings: (1) the development of norms and (2) rigorously controlled testing procedures

• Normal Distribution:  a bell-shaped curve with most scores clustering around the center of the curve

• Static Testing: The traditional approach to testing, in which the test is administered under highly standardized conditions

• Dynamic Testing: the standard testing is followed up with an interaction in which the examiner gives the respondent guided feedback on how to improve performance and observes how the person utilizes the information

Heredity, Environment, and Intelligence

• Intelligence is determined by interacting hereditary and environmental factors.

• Genes account for between 50 and 70 percent of population variation in IQ

• Heritability estimates of intelligence can vary, depending on sample characteristics

Group Differences in Intelligence

• Outcome Bias:  refers to the extent that a test underestimates a person’s true intellectual ability.

• Predictive Bias: occurs if the test successfully predicts criterion measures, such as school or job performance, for some groups but not for others.

• Sterotype Threat:  if they believe that certain behaviors on their part would confirm a negative stereotype in the minds of others

Extremes of Intelligence

• Even people with IQs in the 150s often show discrepancies between specific skills.