Compatibility between object size and response side in grasping: the left hand prefers smaller objects, the right...

Area of Science:

• Cognitive Neuroscience
• Motor Control
• Human Sensorimotor Performance

Background:

• The brain may use a unified neural metric for processing various quantities, including spatial and magnitude information.
• This unified system is hypothesized to be intrinsically linked to motor control processes for sensorimotor transformations.

Purpose of the Study:

• To investigate the compatibility effects between physical object size and spatial response location during a sensorimotor task.
• To determine how the interaction between object size and the hand used for grasping influences movement planning and execution.

Main Methods:

• Participants performed reaching and grasping movements towards objects of varying physical sizes (small or large).
• Movements were executed using either the dominant right hand or the non-dominant left hand.
• Kinematic data, including movement initiation time and grip aperture, were analyzed.

Main Results:

• Movement initiation was faster for the left hand grasping a small object and for the right hand grasping a large object.
• A significant compatibility effect was observed between object size and the hand used, influencing movement planning.
• This interaction also affected the timing of grip aperture kinematics during the grasp.

Conclusions:

• The findings support a strong link between the cognitive representation of object size and spatial parameters in sensorimotor control.
• Object size and response hand compatibility significantly impact the planning and execution of grasping movements.
• This research reinforces the concept of a common neural metric underlying quantity representation and motor control.