Cross-modal exogenous attention and distance effects in vision and hearing

In the present study we investigated cross-modal orienting in vision and he aring by using a cueing task with four different horizontal locations. Our main interest concerned cue-target distance effects, which might further ou r insight in the characteristics of cross-modal spatial attention mechanism s. A very consistent pattern was observed for both the unimodal (cue and ta rget were both visual or auditory) and the cross-modal conditions (cue and target from different modalities). RTs to valid trials were faster than for invalid trials, and, most interestingly, there was a distance effect: RTs increased with greater cue-target distance. This applied to detection of vi sual targets and to localisation of both visual and auditory targets. The t ime interval between cue and target was also varied. Surprisingly, there wa s no indication of inhibition of return even with the longest cue-target in tervals. In order to assess the role of endogenous (strategic) factors in e xogenous spatial attention we increased in two additional experiments the c ue validity from 25% to 80%. This appeared to have no large influence on th e cueing pattern in both the detection and localisation tasks. Currently, i t is assumed that spatial attention is organised in multiple strongly linke d modality-specific systems. The foregoing results are discussed with respe ct to this supposed organisation.