Evidence for dissociable effects of handedness and consistency of hand preference in allocation of attention and movement planning: An EEG investigation

- EEG evidence that handedness and consistency of hand preference can be dissociated.
- Allocation of attention is mainly influenced by handedness.
- Movement planning is modulated by consistency of hand preference.
- Posterior hemispheric asymmetry depends on both aspects of hand laterality.

We studied the potentially dissociable effects of handedness and consistency of hand preference on allocation of attention and movement planning. EEG was recorded from an equally balanced group of left- and right-handed participants with consistent or inconsistent hand preference. The participants viewed photos of graspable objects and responded to the direction of an arrow that was overlaid on the object 1000 ms after object onset. Attention-related ERPs elicited between 100 and 250 ms after object onset were primarily modulated by the participants' handedness. On the other hand, ERPs related to late movement planning processes were modulated only by the consistency of hand preference. Our results suggest that the effects of the consistency of hand preference could be dissociated from those of handedness, the former influencing movement planning processes and the latter more related to allocation of attention.