intelligence: ageing and life outcomes

Are clever children, clever adults?

• some stability was observed over the lifespan but not perfect

• People tended to score better in 1998 (age 77) vs 1932 (age 11) but those who performed well previously also did well later on in life

Murman 2015 - development of cognitive abilities with age

processing speed went down (fluid intelligence) but crystallised abilities (vocabulary) improved

Risk factors of dementia

• education

• Hearing loss

• TBI

• Alcohol

• Obesity

• Smoking

• Depression

• Air pollution

Cognitive reserve

Protective factors to prevent cognitive decline

Schoentgen et al 2020 - cognitive reserve factors

• activities

• Environments

• Biology

• Psychology

• Education

Guzman-velez & tranel 2015 - bilingualism and cognitive reserve

Found bilingualism contributed to cognitive reserve and delayed the onset of Alzheimer’s disease symptoms

Intelligence and educational achievement - deary et al 2007

• IQ at age 11 was a powerful predictor of educational attainment at age 16 (accounting for just over half the difference)

• Shows IQ is a substantial component of GCSE success but not the whole story

Spinath et al - school achievement and cognitive ability

• g proved to be the strongest predictor but self perception and motivation also predict achievement

• Liping et al tried to replicate these findings in china and found no influence of motivation (domain specific?)

IQ and job performance - Schmidt & hunter 1998

age is not a good predictor but intelligence tests, interviews, conscientiousness and integrity are

Emotional intelligence

• Goleman argued EI matter twice as much as IQ and explains 90% difference in performance

• Associated with better social and work relationships, variations in personal heartbeat, ability to recognise and reason about emotional consequences and lower scores of distress.

Batty et al 2009 - IQ and longevity

every SD increase in IQ associated with 32% decrease in mortality risk 20 years later

Calvin et al 2017 - IQ and cause of death

higher IQ associated with lower risk of dying from stoke and heart disease

Deary - IQ and longevity

the benefit to longevity from higher IQ seems to increase all the way up the intelligence scale so that very smart people live longer than smart people who live longer than those with lower IQ

IQ and mental health

• lower childhood IQ associated with an increased risk of schizophrenia, PTSD and depression

• A SD increase in IQ score in youth associated with a risk reduction between 13-43% in mental health difficulties faced in adulthood

Iverson et al 2023 - childhood IQ and self harm/ suicide later in life

Higher childhood IQ significantly associated with reduced risk of self harm but was not significantly associated with suicide risk

Ball et al 2024 - childhood IQ and risk of depression in later life

Higher childhood IQ associated with reduced risk of depression in later life