Affiliations: Department of Cognitive Sciences and Education,
University of Trento, Trento, Italy | Center for Mind/Brain Sciences, University of Trento,
Trento, Italy | Christoph-Dornier-Foundation, Bremen, Germany
Note: [] Corresponding author: Davide Bottari, Dipartimento di Scienze
della Cognizione e della Formazione, Università di Trento, Corso Bettini
31, 38068 Rovereto, Italy. Tel.: +39 464 808674; Fax: +39 464 808654; E-mail:
[email protected]
Abstract: Purpose: 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.
