Tool Use and Generalized Motor Programs: We All Are Natural Born Poly-Dexters

Area of Science:

• Cognitive Neuroscience
• Motor Control
• Human Evolution

Background:

• The common belief posits human tool use relies on hand-specific motor programs.
• This implies using non-hand body parts (end-effectors) for tool manipulation should be difficult.
• Existing theories suggest manual dexterity is primary for tool use.

Purpose of the Study:

• To investigate if tool-use motor programs are hand-centered.
• To explore the adaptability of tool-use actions across different end-effectors.
• To challenge the traditional view of manual dexterity preceding tool-use skills.

Main Methods:

• Participants performed three distinct tool-use actions.
• Four different end-effectors were utilized: right foot, right elbow, left hand, and right hand.
• Spatiotemporal parameters of tool use were analyzed across end-effectors.

Main Results:

• Participants effectively performed tool-use actions with all tested end-effectors.
• Crucially, the spatiotemporal parameters of tool use remained consistent across different end-effectors.
• This demonstrates a phenomenon termed 'poly-dexterity'.

Conclusions:

• Tool use is not reliant on hand-specific motor programs.
• General motor programs can be applied to various end-effectors for tool manipulation.
• Manual dexterity may have evolved after, rather than before, tool-use capabilities.