Matsuyoshi, D., Osaka, M., Osaka, N.
Age and individual differences in visual working memory deficit induced by overload
Frontiers in Psychology, 5, 394、2014
Many studies on working memory have assumed that one can determine an
individual’s fixed memory capacity. In the current study, we took an individual
differences approach to investigate whether visual working memory (VWM) capacity
was stable irrespective of the number of to-be-remembered objects and participant age.
Younger and older adults performed a change detection task using several
objects defined by color. Results showed wide variability in VWM capacity across
memory set sizes, age, and individuals. A marked decrease in the number of objects
held in VWM was observed in both younger and older adults with low memory capacity,
but not among high-capacity individuals, when set size went well beyond the limits of
VWM capacity. n addition, a decrease in the number of objects held in VWM was
alleviated among low-capacity younger adults by increasing VWM encoding time; however,
increasing encoding time did not benefit low-capacity older adults. These findings
suggest that low-capacity individuals are likely to show decreases in VWM capacity
induced by overload, and aging exacerbates this deficit such that it can not be
recovered by simply increasing encoding time. Overall, our findings challenge the
prevailing assumption that VWM capacity is fixed and stable, encouraging are
vision to the strict view that VWM capacity is constrained by a fixed number of
distinct “slots” in which high-resolution object representations are stored.