Interindividual Differences in Cognitive Variability Are Ubiquitous and Distinct From Mean Performance in a Battery...

Area of Science:

• Cognitive psychology
• Neuroscience
• Psychometrics

Background:

• Cognitive task performance exhibits moment-to-moment fluctuations within individuals.
• Historically, cognitive variability has been treated as measurement error, overshadowing its potential significance.
• Research has predominantly focused on aggregate performance metrics, like mean performance, rather than response variability.

Purpose of the Study:

• To investigate cognitive variability as a crucial and intrinsic phenotype.
• To analyze dense trial-by-trial data using advanced time-series methodologies.
• To determine if cognitive variability represents reliable individual differences across diverse tasks.

Main Methods:

• Utilized dense trial-by-trial data from over 7 million trials across eleven distinct cognitive tasks.
• Applied novel time-series analytical methods to quantify cognitive fluctuations.
• Examined interindividual differences in response variability and compared them to mean performance.

Main Results:

• Identified highly reliable interindividual differences in cognitive variability across all examined tasks.
• Demonstrated that these variability differences are qualitatively and quantitatively distinct from mean performance.
• Found that a single, global dimension cannot adequately explain cognitive variability across tasks.

Conclusions:

• Cognitive variability is a fundamental aspect of cognition, not merely error.
• Individual differences in cognitive variability offer a novel phenotype for understanding cognitive function.
• Findings challenge existing global mechanisms of cognitive variability and suggest more nuanced models are needed.