Lecture 9 - Intelligence Flashcards
What is intelligence?
Latent construct defined as:
Ability to carry out abstract thinking (Terman, 1916), ability to learn/having learned, to adjust oneself to the environment (Calvin, 1923), what intelligence tests measure (Boring, 1923)
Global concept that involves individual’s ability to act purposefully, think rationally, deal effectively with environment (Wechsler, 1953)
General ability to reason/plan/solve problems, think abstractly, learn quickly, learn from experience (Gottfredson, 2000)
What is IQ? (intelligence quotient)
Originally measure of deviation from mental age/chronological age
IQ = (mental age/chronological age) x 100
Wechsler (1975) redefined as standardised score showing deviation from average score, normally distributed w/ SD of 15
What are examples of intelligence test items?
Digit Span: repeat each string of numbers in order said
Letter Number Sequencing: rearrange items so you say numbers first in ascending order than letters in alphabetical order
Proverb task (what does this proverb mean?)
Trail making: join circles in numerical order as quickly as possible
Reasoning tasks
What is g (general) intelligence?
Charles Spearman (1863-1945)
Common mental energy underlying performance on all tests, indifference of the indicator
What is the hierarchy of intelligence?
4 broad domains under g – verbal ability, working memory, visual-spatial reasoning, processing speed - with diff tasks measuring them
Verbal ability: vocab reading, synonyms
Working memory: digit span, letter-number sequencing
Visual-spatial reasoning: box folding, hidden figures
Processing speed: reaction time, trail-making
No consensus on precise hierarchical structure/content
How are intelligence and health linked?
Chamorro-Premuzic (2013): IQ correlates w/ academic achievement, job performance, longevity
What is cognitive epidemiology?
Examination of cognition/IQ as correlate of health/mortality
Reverse Causation: poor health can influence IQ
Confounding effects of (eg.) Socio-economic status
What do longitudinal designs do for health/intelligence research?
Longitudinal designs help establish causality
What are examples of longitudinal studies for health/intelligence?
Scottish Birth Cohort Studies: 1931, gathered to plan how to measure mental ability of Scottish nation’s children, tested entire nation
Samples of participants traced/recruited into cohort studies
Moray House Test: 71 items including math, following directions, proverbs, analogies, reasoning, etc. (test took that year), scores correlate with Raven’s Matrices + Stanford-Binet à valid measures of 11 year old IQ
Found average of those who were dead was lower than those still alive, smaller effect in men than women
Significant correlation between age-11 IQ + age of death after controlling for SES
What are examples of cohort studies?
Swedish Conscripts Study (men took IQ test in military service), Nun Study (linguistic measures from autobiographies), Danish Metropolit Study (boys in Copenhagen given IQ test in social mobility study)
What did Batty/Deary/Gottfredson find in their systematic review?
9 studies show higher IQ in first 20 years of life linked with lower mortality even after adjusting for childhood SES
What are possible pathways for IQ-Health link?
Deary (2008):
IQ to education to employment prospects to adult SES status
Adjusting for adult SES reduces IQ-longevity association
IQ to health literacy/health behaviours (medication adherence, health eating/physical activity/wearing seatbelts/hangover frequencies)
Suboptimal neural development to IQ/Psychiatric Burden
Low IQ associated with psychiatric disorders BUT controlling for birth weight does not eliminate IQ-longevity links
Body system integrity to IQ/health problems
Bodily symmetry associated with IQ
What are links between intelligence and happiness?
Ali et al. (2013): mixed results from previous studies, recruited representative sample of 7403 English adults + measured happiness + verbal IQ with National Adult Reading Test + potential mediating variables that may account for IQ-happiness relationship
Found that high IQ predicted likelihood of being happy
What variables mediate link between intelligence and happiness?
Dependency in activities of daily living, income, neurotic symptoms, self-reported health, marital status, social participation
Further studies needed to test mechanisms longitudinally
