Bimanual interference associated with the selection of target locations

Area of Science:

• Cognitive psychology
• Motor control
• Human movement science

Background:

• Bimanual reaching movements involve coordinating two hands to reach for targets.
• Interference during bimanual tasks can arise from various stages of movement preparation.
• Understanding the source of this interference is crucial for explaining complex motor behaviors.

Purpose of the Study:

• To identify the specific locus of interference during bimanual reaching movement preparation.
• To differentiate between interference occurring during target selection versus motor programming.
• To investigate the role of response rule segregation in bimanual interference.

Main Methods:

• Four experiments were conducted involving bimanual reaching tasks.
• Target locations were defined by color, with same or different color targets for each hand.
• Movement amplitudes and directions were varied across experiments.
• Reaction times were measured for unimanual and bimanual movements with and without distractors.

Main Results:

• Faster movement initiation was observed for movements to same-colored targets compared to different-colored targets.
• Reaction time costs were evident in unimanual movements when presented with distractors for the contralateral hand.
• These findings suggest interference originates in the target selection stage.

Conclusions:

• Interference in bimanual reaching preparation stems from difficulties in target selection, not motor programming.
• The observed interference is linked to challenges in segregating response rules associated with each hand.
• This highlights the importance of distinct response mapping for efficient bimanual coordination.