Hand Dominance Increases During Concurrent Bimanual Tracking: The Role of Gaze Contingencies and Visual Display

Area of Science:

• Neuroscience
• Human Factors
• Motor Control

Background:

• Operators often perform distinct tasks with each hand simultaneously.
• Limited research exists on how dual-tasking affects the inherent right-hand visuomotor advantage in right-handed individuals.

Purpose of the Study:

• To investigate the impact of dual-tasking on hand dominance during a bimanual visuomotor task.
• To determine if the right-hand advantage persists, increases, or diminishes when performing concurrent tasks with both hands.

Main Methods:

• Twenty-eight right-handed participants performed 2D visuomotor tracking under unimanual and bimanual conditions.
• Tracking performance was assessed by measuring the mean cursor-target distance for each hand.
• Gaze contingencies and visual displays were manipulated, including free gaze and head-straight fixation.

Main Results:

• A significant right-hand advantage was observed in unimanual conditions.
• In bimanual tasks with free gaze, performance decreased for both hands, with a greater deficit in the left hand, amplifying the right-hand advantage.
• Fixating straight ahead substantially reduced manual asymmetry without compromising overall tracking performance.

Conclusions:

• Right-handed individuals exhibit a natural prioritization of their dominant hand during bimanual visuomotor tasks.
• Instructing participants to fixate straight ahead effectively mitigates this hand dominance.
• Fixating straight ahead may be a beneficial strategy for operators, such as pilots, needing to divide tasks equally between hands.