Examination of the common cause account in a population-based longitudinal study with narrow age cohort design.
BACKGROUND
The common cause account suggests that there is a third factor causing aging effects in both sensory and cognitive functioning, hypothesized to be the integrity of the central nervous system [Lindenberger and Baltes; Psychol Aging 1994;9:339-355]. Importantly, the common cause account was developed based on cross-sectional data, which are especially biased by cohort effects. However, cohort effects can be controlled for in narrow age cohort (NAC) designs and by longitudinal examination. Findings from the few longitudinal studies that have studied the relation between age-related changes in sensory and cognitive functions are complex and give only partial support to the common cause account.


OBJECTIVE
The present paper examines the common cause account within a longitudinal setting.


METHODS
Our study is unique in the sense that it tests the common cause account within a longitudinal NAC design using data from the Betula project. The participants (n = 1,057) were in the age range of 45-90 years.


RESULTS
The findings indicate that the relationship between sensory and memory functioning in both a longitudinal age-heterogeneous and a longitudinal NAC design are much weaker than that detected by an age-heterogeneous cross-sectional design.


CONCLUSIONS
The demonstrated weak age-associated sensory-cognitive link raises questions regarding the explanatory value of the common cause account and related theoretical accounts for accounting for age-related cognitive changes.
Sternäng
Ola
O
Department of Psychology, Stockholm University, Stockholm, Sweden. ola.sternang @ psychology.su.se
Jonsson
Bert
B
Wahlin
Ake
A
Nyberg
Lars
L
Nilsson
Lars-Göran
LG
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology; D002490:Central Nervous System / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D015988:Cohort Effect; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D012107:Research Design; D012677:Sensation / Q000502:physiology*; D013223:Statistics as Topic; D013548:Sweden / Q000453:epidemiology