title: Variations in cognitive abilities across the life course: Cross-sectional evidence fromUnderstanding Society: The UK Household Longitudinal Study.
abstract: BACKGROUND
  Populations worldwide are aging. Cognitive decline is an important precursor of dementia, illness and death and, even within the normal range, is associated with poorer performance on everyday tasks. However, the impact of age on cognitive function does not always receive the attention it deserves.
  
  
  METHODS
  We have explored cross-sectional associations of age with five cognitive tests (word recall, verbal fluency, subtraction, number sequence, and numerical problem solving) in a large representative sample of over 40,000 men and women aged 16 to 100 living in the UK.
  
  
  RESULTS
  Women performed better on word recall tests and men had higher scores for subtraction, number sequence and numerical problem solving. However, age-cognition associations were generally similar in both genders. Mean word recall and number sequence scores decreased from early adulthood with steeper declines from the mid-60s onwards Verbal fluency, subtraction and numerical problem solving scores remained stable or increased from early to mid-adulthood, followed by approximately linear declines from around age 60. Performance on all tests was progressively lower in respondents with increasingly worse self-rated health and memory. Age-related declines in word recall, verbal fluency and number sequence started earlier in those with the worst self-rated health. There was no compelling evidence for age dedifferentiation (that the general factor of cognitive ability changes in strength with age).
  
  
  CONCLUSIONS
  We have confirmed previously observed patterns of cognitive aging using a large representative population sample.
authors.affiliation: Institute for Social and Economic Research, University of Essex, Colchester CO4 3SQ, UK; MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Glasgow G12 8RZ, UK.
authors.forename: Elise
authors.initials: E
authors.lastname: Whitley
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, Edinburgh, UK.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, Edinburgh, UK.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Ritchie
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, Edinburgh, UK; Department of Epidemiology and Public Health, University College London, London, UK.
authors.forename: G David
authors.initials: GD
authors.lastname: Batty
authors.affiliation: Institute for Social and Economic Research, University of Essex, Colchester CO4 3SQ, UK.
authors.forename: Meena
authors.initials: M
authors.lastname: Kumari
authors.affiliation: Institute for Social and Economic Research, University of Essex, Colchester CO4 3SQ, UK.
authors.forename: Michaela
authors.initials: M
authors.lastname: Benzeval
keywords: Age differences; Aging; Cognitive ability; Memory