Abstract
Centrally presented gaze and arrow cues cause covert shifts of attention even when they are uninformative. The validity effect of the cues is evident on manual reaction time (RT), as responses are faster for targets appearing at cued locations relative to those appearing at uncued locations. Interestingly, previous research on covert orienting to the periphery suggested that early profound deaf adults were less susceptible to uninformative gaze cues, though were equally if not more affected by non-social arrow cues (Heimler et al., 2015). The aim of the present work was to investigate whether spontaneous eye movement behaviour helps explain the absence of social cuing in the deaf observers. We tracked the gaze of age-matched deaf (n = 24) and hearing observers (n = 24) performing a peripheral discrimination task with uninformative central cues (gaze vs. arrow), SOA (250 vs. 750 ms) and cue validity (valid vs. invalid) as within-subject factors. In both groups, the cuing effect on RT was comparable for the gaze- and arrow-cue, although deaf observers responded significantly slower than hearing controls. While deaf and hearing observers responded equally to the cue presented in isolation, deaf observers relied significantly more on eye movements than hearing controls once the discrimination target was presented. Notably, in the deaf group, saccade latency was affected by cue type but not by cue validity, while for landing position the reverse was true. Saccade landing position was strongly related to the magnitude of the validity effect on RT, such that the greater the difference in saccade landing position between invalid and valid trials, the greater the difference in manual RT between invalid and valid trials. This work suggests that the contribution of overt selection in central cuing of attention is enhanced in deaf adults and determines the attentional performance, irrespective of cue type.
Acknowledgement: Autonomous Province of Trento (Italy), call “Grandi Progetti 2012”, project “Characterizing and improving brain mechanisms of attention -ATTEND”