Cross-modal congruency between haptic and visual objects affects involuntary shifts in spatial attention

Previous research has shown that task-irrelevant auditory/haptic input semantically congruent with a target visual object facilitates visual search, indicating that cross-modal congruency influences goal-directed attentional control. The present study examined whether haptic input involuntarily shifts spatial attention to the congruent visual object even though it was not a search target. Participants identified the arrow direction presented above or below a central gaze fixation point while clasping a specifically shaped item in their hand. Two task-irrelevant pictures with specific shapes preceded the arrow. Results showed a significant interaction between visual and haptic shapes: Participants responded faster when the visual object shared the shape of the item clasped in their hand than when the two shapes differed, indicating that haptic-visual shape congruency modulates spatial attention. Thus, cross-modal congruency can affect involuntary attentional orienting as well as goal-directed attentional control.