Contribution of a common ability in average and variability judgments.

Area of Science:

• Cognitive Psychology
• Visual Perception
• Psychophysics

Background:

• Ensemble perception allows estimation of statistical properties (mean, variance, numerosity) of visual features in object groups.
• Previous research suggested independent abilities for different statistical judgments (e.g., mean vs. variance).

Purpose of the Study:

• To investigate the independence of abilities for judging average and variability of the same visual feature.
• To provide robust evidence by testing a large sample with a pre-registered sequential design.

Main Methods:

• A large-scale study using a pre-registered open-ended sequential design.
• Estimation of shared variance in abilities for ensemble judgments (average size, size variability).
• Control for individual differences in discriminating single object sizes.

Main Results:

• Abilities to judge average size and size variability of circles are positively correlated.
• This correlation persists even when controlling for single-item size discrimination ability.

Conclusions:

• The findings refute the hypothesis that judging average and variability for the same feature rely on completely independent cognitive abilities.
• Ensemble perception of statistical properties may involve partially shared underlying mechanisms.