| |
Abstract:
A novel experiment was designed to investigate goal-relevant
behaviour in a group of 38 normal elderly subjects. All subjects
showed neglect of task requirements even though they were
understood and subsequently recalled. Performance on the task was
highly correlated with measures of fluid intelligence (Spearman's
g), with subjects at the lower end of the g distribution producing
almost complete neglect of one or more requirements on all trials.
The critical aspect of this task demanded the suppression of a
combined response tendency arising from simultaneously activated,
but no longer relevant, requirements ("cognitive reversal"). In a
group of 29 subjects matched for age and g, removal of this element
from the task eradicated the relationship with g. The relationship
with g demonstrated by the original experiment was subsequently
replicated in a group of younger subjects. A neuropsychological
study was set up with 20 patients with unilateral lesions
restricted to the frontal lobes. A sample of normal subjects,
matched for age, sex, education and premorbid intelligence were
also assessed. In both groups, the relationship between performance
and g was maintained. Interactions between task performance, g and
side of lesion were also observed. Anatomical and theoretical
explanations for the results are discussed.
|
