When One Hand Aims for a Target with Some Index

Question

When one hand aims for a target with some index of difficulty ID), its movement time
A) Shortens if the other hand aims for a target with a larger ID
B) Shortens if the other hand aims for a target with a smaller ID
C) Lengthens if the other hand aims for a target with a larger ID
D) Lengthens if the other hand aims for a target with a smaller ID

Accepted Answer

When both hands are involved in aiming tasks simultaneously, movement time is longer compared to a situation when only one hand is used. This effect can be explained by the interference that occurs between the two movement plans. If the other hand aims for a target with a larger ID, it will require more cognitive and motor resources, which will interfere with the movement of the other hand and lead to a longer movement time. Therefore, the movement time of the hand aiming for a target with a smaller ID may also be affected, but it will be less than the effect on the hand with a larger ID.