Intelligence, Health and Wellbeing

Intelligence, Health and Wellbeing

1. What is Intelligence?

   • A latent construct defined as:
     • Ability to carry out abstract thinking (Terman, 1916)
     • Ability to learn to adjust oneself to the environment (Calvin, 1923)
     • What intelligence tests measure
     • Global concept that involves an individual's ability to act purposefully, think rationally, deal effectively with environment
     • General ability to reason, plan, solve problems, think abstractly, learn quickly, learn from experience
   • IQ: Intelligence Quotient
     • Originally a measure of deviation of mental age from chronological age
     • Wechsler (1975) - standardised score showing deviation
   • Intelligence Test Items
     • Digit span
     • Letter number sequencing
     • Proverb task
     • Trail-Making
     • Reasoning tasks
   • G(eneral) Intelligence
     • Charles Spearman (1863-1945)
       • Common mental energy underlying performance on all tasks
       • Indifference of the indicator
     • Hierarchy of intelligence
       • No consensus on precise hierarchical structure/content
       • Individual differences
       • Cognitive psychology

2. Cognitive Epidemiology

   • Intelligence and Health
     • Chamorro-Premuzic (2013)
       • IQ correlates with academic achievement, job performance and longevity
     • Cognitive epidemiology
       • The examination of cognition/IQ as a correlate of health and mortality (Deary and Batty, 2007)
       • Reverse causation
       • Confounding effects, e.g. SES
       • Longitudinal designs help to establish causality
       • Scottish Birth Cohort Studies
         • The Scottish Mental Surveys
         • Samples of these participants were traced and recruited into cohort studies
         • Moray House test
         • Whalley and Deary (2001) - significant correlation between age 11 IQ and age of death
       • Cohort Studies
         • Swedish Conscripts Study
         • Nun Study
         • Danish Metropolit Study
         • Limitations
           • Dataset not originally geared for a cognitive epidemiology study
           • Differ in validity of IQ measures
           • Differ in robustness of SES estimates

3. Mechanisms of IQ Effects

   • IQ-Health Causal Mechanisms
     • Deary (2008)
       • High IQ confers a survival advantage - more likely higher SES status
       • High IQ leads to high health literacy
       • Early life event that impacts on early brain development
       • Higher IQ is a marker of body system integrity
   • Intelligence and Happiness
     • Ali et al. (2013)
       • Mixed results from previous studies
       • Representative sample of 7,403 English adults
       • Measured happiness that was intentionally very simple
       • Verbal IQ measured with NART
       • Measured potential mediating variables that may accoutn for any IQ-happiness relationship
       • High IQ predicted likelihood of being happy
       • Relationship mediated by several things
       • Further studies needed to test mechanisms longitudinally