Examining the locus of age effects on complex span tasks

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human Aging Research

Background:

• Complex span tasks are widely used to assess working memory capacity.
• Aging is associated with declines in various cognitive functions, including working memory and processing speed.

Purpose of the Study:

• To identify the specific cognitive mechanisms underlying age-related differences in complex span task performance.
• To differentiate the contributions of working memory components and processing speed to age effects.

Main Methods:

• Hierarchical regression analyses were employed to statistically control for individual differences in storage capacity and processing speed.
• Complex span task performance was evaluated across different age groups.
• Span size was calibrated to individual word span performance to assess storage capacity effects.

Main Results:

• Significant age differences were observed in storage capacity, language processing speed, and lower-level processing speed.
• Controlling for storage capacity and lower-level processing speed substantially reduced the age effect on complex span tasks.
• The combined effect of storage capacity and lower-level processing speed accounted for the majority of the age-related variance in complex span performance.

Conclusions:

• Working memory storage capacity and processing speed are key determinants of age-related differences in complex span tasks.
• These factors play independent and significant roles in cognitive aging.
• Alternative explanations, such as inhibition or concurrent task demands, do not fully account for the observed age effects.