Human behavioral complexity peaks at age 25.

Area of Science:

• Cognitive Psychology
• Developmental Psychology
• Neuroscience

Background:

• Random Item Generation (RIG) tasks are utilized to evaluate higher cognitive functions like inhibition and sustained attention.
• These tasks also engage an individual's approximate sense of complexity.
• Previous research indicates aging negatively impacts pseudo-random productions, but the lifespan trajectory of cognitive complexity remains underexplored.

Purpose of the Study:

• To investigate the developmental trajectory of cognitive complexity across the human lifespan.
• To assess the utility of Random Item Generation tasks in estimating cognitive abilities throughout life.

Main Methods:

• Analysis of human responses to five common Random Item Generation tasks.
• Utilized a large sample size (n = 3429) to examine complexity across different age groups.
• Employed algorithmic complexity estimation on response strings as short as 10 items.

Main Results:

• The developmental curve for estimated algorithmic complexity mirrors expected patterns for higher cognitive abilities.
• A performance peak was observed around age 25, with a noticeable decline beginning around age 60.
• Reliable complexity estimation and age-dependent decline documentation are achievable with very short response strings (10 items).

Conclusions:

• Random Item Generation tasks provide valid estimations of cognitive abilities across the lifespan.
• Cognitive complexity, as measured by RIG tasks, follows a developmental curve with a peak in early adulthood and a subsequent decline.
• The findings support the use of RIG tasks for studying age-related cognitive changes.