Cognitive Decline

Question 1

Distinguish fluid intelligence from crystalised

Answer 1

Fluid intelligence refers to the core cognitive mechanisms involving mental abilities to help us solve novel problems and reason.

Crystalised intelligence is acquired through learning and experience, including numeracy, verbal ability and the knowledge of facts. Crystalised skills decline at a slower rate compared to fluid intelligence.

Whilst these two forms of intelligence tap into different cognitive mechanisms, they are positively correlated, indicating an underlying common “g” factor.

Question 2

Outline general intelligence

Answer 2

General cognitive ability - “g” factor has been found to be a predictor of school achievement and later professional achievement.

Cognitive ability has also been associated with longevity, even when socio-economic factors have been controlled for.

Question 3

Describe age-associated cognitive decline

Answer 3

Age-associated cognitive decline is loss of cognitive performance due to chronological ageing, rather than other factors such as brain injury.

Cognitive decline typically starts at middle age and accelerates with age. It is dependent on what type of cognitive skill is being assessed, with crystalised skills showing a slower rate of decline compared to fluid intelligence.

Cognitive decline is less understood that general cognitive performance.

Factors such as genetics, socio-economic status and lifestyle have been found to account for 81% of the variance within cognitive performance, but only 16% of the variance in cognitive decline.

Differences within cognitive decline between individuals tends to be smaller in earlier adulthood, but these gaps can become much larger in older age. This makes the trajectory of cognitive decline hard to predict.

Question 4

Describe dementia

Answer 4

Dementia is the general term for impaired thinking, memory and ability to reason.

It occurs when cognitive decline reaches a certain threshold, degrading ability to function cognitively.

Certain biomarkers have been identified for dementia in recent years, possibly allowing for more targeted treatments. However, there still remains little predictive power in early phases.

Question 5

Describe the relationship between education and cognitive decline with reference to a study.

Answer 5

Higher education is often associated with lower rates of dementia. Dementia is similarly related to cognitive decline. However, no such association has been found between education and cognitive decline.

Sala et al., 2023 conducted a longitudinal study across 25 years on over 1800 individuals aged 40-80 from Japan.

Across 9 measurement waves their crystallised and fluid intelligence was measured.

Adults who started the study at a younger age typically showed a slower rate of cognitive decline than those starting at an older age.

Education is positively associated with the baseline for general intelligence and is correlated with better lifestyles and environments. Therefore, more educated people start at a higher baseline and are at a reduced risk for pathological brain damage.

Education is not a substantial protective factor in against age-associated cognitive decline; instead it lowers dementia risk by raising the baseline for cognitive decline and improving overall brain health