Hand use for grasping in a bimanual task: evidence for different roles?

Area of Science:

• Neuroscience
• Human Motor Control
• Cognitive Psychology

Background:

• Bimanual object interaction often involves specialized roles for each hand.
• The proposed division of labor suggests the right hand performs precise manipulation, while the left hand stabilizes the object.

Purpose of the Study:

• To investigate if the proposed division of labor influences hand use during visually guided grasping.
• To determine how environmental constraints affect hand specialization in bimanual tasks.

Main Methods:

• Three experiments were conducted with right-handed individuals assembling 3D models using building blocks.
• Participants built models on a tabletop, with variations in base plate size (comfortable, large, small).
• Hand use for grasping and stabilizing was recorded during the visually guided task.

Main Results:

• In the absence of constraints, the right hand was predominantly used for grasping, and the left for stabilization.
• A large base plate increased left-hand grasping, potentially due to reduced need for stabilization and interference with contralateral movements.
• A small base plate maintained right-hand grasping preference, indicating stabilization duties were more critical than contralateral movement interference.

Conclusions:

• Environmental constraints significantly modulate hand use during bimanual object interaction.
• The findings support a left-hemisphere advantage for right-hand control in grasping.
• Hand specialization in bimanual tasks is adaptable and influenced by task demands and environmental factors.