Nature of Intelligence

• Intelligence- The construct measured by traditional intelligence tests and portrayed by an IQ score.

• Definition of intelligence varies, however, Anastasi defines as, "the ability necessary for survival and advancement within a particular culture".

• These abilities differ from time to time and culture to culture.

• Different abilities are more valuable in different cultures.

Etiology of Intelligence

• Heritability Index and IQ- • The HI is the degree to which IQ is determined by inherited biological factors vs. environmental factors.

• Difficult to precisely determine HI due to the difficulty teasing out environmental factors from biological factors.

• For example, when Identical twins are separated at birth, they are not randomly assigned to different environments.

Etiology of IQ (continued)

• Problems with generalizing from twin research due to the greater susceptibility of twins to prenatal traumas.

• HI's are applicable to populations not specific individuals.

• Also, does not measure the degree of modifiability.

• IQ is modifiable and even though HI percentages are high, the amount of variance not explained is significant.

Etiology of Intelligence• Bidirectional

•Personality characteristics determine the degree to which individual spend learning regarding activities within their environments (Atkinson Schema).

•Intelligence also influences the degree to which environmental characteristics direct individual’s attention.

Etiology of Intelligence• Biological Factors

• Prenatal and perinatal environments• Nutritional • Stimulation factors

• Personal/Cultural Factors • Low achievement drive

• Antisocial attitudes toward authority

• Poor self-concept

Nature of Intelligence

• Fluid vs. Crystallized Intelligence-

• Fluid Intelligence- Nonverbal, less culturally determined mental abilities.

• Crystallized Intelligence- Typically more verbal, learned skills/abilities that are more culturally dependent.

Factor Analysis

• Early Factorization of Intelligence-

• Single Factor- “Big G”(General Factor)- (Charles Spearman)

• Multiple Factors “Little g’s” (L. L. Thurstone) Different types of IQ including verbal comprehension, word fluency, arithmetical abilities, spatial abilities, and associative memory

Factor Analysis (continued)

• Hierarchical Model- • General Ability – Full-Scale IQ

• Major Factors – Verbal vs. Performance abilities.

Factor Analysis (continued)

• Minor Factors • Stanford-Binet

– Fluid Reasoning– Knowledge– Abstract/Visual Reasoning – Quantitative Reasoning– Working Memory.

• WISC-IV– Verbal Comprehension– Perceptual Reasoning– Working Memory– Processing Speed.

Factor Analysis (continued)

• Specific Factors (examples)– Vocabulary– Information– Block Design– Picture Completion

Derivation of IQ Factors

• Factors are derived by examining the intercorrelations among different subscale from intelligence tests.

• Factors may contain different subscales depending on the age of the individuals being tested.

Nonfactors in Traditional IQ Tests

• Many items which could be measures of intelligence have never been assessed as such:

• Creativity• Musical/artistic ability• Emotional insight• Attitudinal variables such as "eagerness to please”

Summary

• The construct of IQ continues to be most closely aligned with academically based, verbal measures of performance.