Hand preference on unimanual and bimanual tasks in Barbary macaques (Macaca sylvanus)

Area of Science:

• Primate Behavior
• Comparative Psychology
• Neuroscience

Background:

• Group-level handedness in non-human primates is debated due to inconsistent research findings.
• Bimanual tasks are considered more effective than unimanual tasks for revealing hand preferences in primates.

Purpose of the Study:

• To investigate manual lateralization in Barbary macaques (Macaca sylvanus).
• To compare hand preferences during unimanual and bimanual tasks.
• To assess the validity of bimanual tasks for studying primate handedness.

Main Methods:

• Fifteen Barbary macaques performed unimanual food reaching and a bimanual task involving holding an apparatus while reaching for food.
• Hand use data were collected for both task types.
• Statistical analysis was used to determine group-level and individual-level hand preferences.

Main Results:

• No significant group-level hand preference was observed in the unimanual task.
• A significant right-hand bias was found in the bimanual task.
• Individual-level hand preferences were more prevalent and stronger in the bimanual task compared to the unimanual task.

Conclusions:

• Barbary macaques exhibit a right-hand preference in coordinated bimanual tasks.
• Bimanual tasks are more sensitive and appropriate for assessing handedness in non-human primates.
• These findings contribute to the understanding of primate lateralization and the evolution of handedness.