Enhanced reactivity to visual stimuli in deaf individuals.
OBJECTIVE
Several studies have reported faster response time to visual stimuli in profoundly deaf individuals. This result is often linked to the processing of peripheral targets, and it is assumed to occur in relation to attention orienting. We evaluated whether enhanced reactivity to visual events in profoundly deaf individuals can be explained by faster orienting of visual attention alone.


METHODS
We examined 11 deaf individuals and 11 hearing controls, in a simple detection task and in a shape discrimination task. While simple detection can be performed under distributed attention, shape discrimination requires orienting of spatial attention to the target. The same visual targets served for both tasks, presented at central or peripheral locations and corrected for cortical magnification.


RESULTS
The simple detection task revealed faster RTs in deaf than hearing controls, regardless of target location. Moreover, while hearing controls paid a cost in responding to peripheral than central targets, deaf participants performed equally well regardless of target eccentricity. In the shape discrimination task deaf never outperformed hearing controls.


CONCLUSIONS
These findings reveal that enhanced reactivity to visual stimuli in the deaf cannot be explained only by faster orienting of visual attention and can emerge for central as well as peripheral targets. Moreover, the persisting advantage for peripheral locations in the deaf, observed here under distributed attention, suggests that this spatially-selective effect could result from reorganised sensory processing rather than different attentional gradients.
Bottari
Davide
D
Department of Cognitive Sciences and Education, University of Trento, Trento, Italy. davide.bottari@unitn.it
Nava
Elena
E
Ley
Pia
P
Pavani
Francesco
F
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D003638:Deafness / Q000503:physiopathology*; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011930:Reaction Time / Q000502:physiology*; D017603:Signal Detection, Psychological / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult