Finger Counting and (2D:4D) Digit Ratio in Spatial-Numerical Association

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human Behavior

Background:

• Spatial-numerical association is influenced by cultural finger counting habits.
• Digit ratio (2D:4D ratio), an indicator of prenatal androgen exposure, affects spatial-numerical representation.
• The independent or interactive effects of finger counting habits and digit ratio on spatial-numerical association remain unclear.

Purpose of the Study:

• To investigate the independent and interactive effects of finger counting habits and digit ratio on spatial-numerical association.
• To explore how these factors influence number-to-position tasks, digit string bisection, and physical line bisection.

Main Methods:

• Study 1: Recorded digit ratio and finger counting mapping in right-handers performing numerical tasks.
• Study 2: Recorded digit ratio and finger counting mapping in both right and left-handers.
• Utilized number-to-position, digit string bisection, and physical line bisection tasks.

Main Results:

• A finger counting effect was observed in the number-to-position task, with a significant interaction between factors.
• A digit ratio effect was found in the digit string bisection task.
• Finger counting habit influenced spatial biases in both numerical tasks for all participants.
• A significant interaction between finger counting and digit ratio was found in numerical tasks for left-handers.

Conclusions:

• Finger counting habits and digit ratio independently and interactively influence spatial-numerical associations.
• The findings highlight the embodied nature of spatial-numerical cognition.
• Left-handers show a more pronounced interaction between finger counting and digit ratio in numerical tasks.