Sensorimotor mechanisms selective to numerosity derived from individual differences

Area of Science:

• Cognitive Neuroscience
• Psychology
• Sensory Systems

Background:

• Previous research indicated a sensorimotor numerosity system influencing perceived quantity through finger-tapping adaptation.
• This system's existence was previously evidenced solely through adaptation paradigms.

Purpose of the Study:

• To extend findings on the sensorimotor numerosity system using covariance analysis.
• To investigate the neural basis of number-action translation by identifying underlying channels.

Main Methods:

• Employed a covariance technique to analyze precision in reproducing target number presses without counting.
• Utilized factor analysis and principal component analysis to identify numerical processing channels.
• Conducted control experiments to exclude non-numerical strategies like tapping frequency.

Main Results:

• High positive correlations in reproduction precision for nearby target numbers, decreasing with numerical distance, indicating tuning selectivity.
• Factor analysis identified two distinct factors for low and high numbers.
• Principal component analysis revealed two bell-shaped covariance channels with different numerical peaks.

Conclusions:

• The findings support the existence of a sensorimotor numerosity system.
• Evidence suggests at least two distinct sensorimotor number channels translate symbolic numbers into action sequences.