The present research demonstrates that the limitations of congenitally blind people in tasks requiring the processing of mental images are specifically related to the absence of binocular vision and not to the absence of vision per se. We contrasted three different groups of participants: sighted; visually impaired, with reduced binocular vision; monocular, with a normal visual acuity although in one eye only. Visually impaired participants (i.e. blurred vision) show a pattern of performance comparable to that of the sighted. In contrast, monocular participants show a similar pattern of performance to congenitally blind individuals despite being able to see perfectly well. These results shed new light on the relationship between perception and imagery and on the characteristics of sequential and simultaneous processes in the human brain.
aDepartment of Psychology, University of Pavia, Pavia
bOphthalmology Unit, Melegnano Hospital, Melegnano
cDepartment of General Psychology, University of Padova, Padova
dLaboratory of Clinical Biochemistry, University of Pisa, Pisa, Italy
Correspondence and requests for reprints to Dr Tomaso Vecchi, PhD, Department of Psychology, University of Pavia, P.za Botta 6, 27100 Pavia, Italy
Fax: +390382986272; e-mail: firstname.lastname@example.org
Sponsorship: This research was supported by the European Union (Grant IST-2001–38040), by the Italian Ministero dell'Istruzione, dell'Università e della Ricerca (Grant RBNE018ET9-003 and Grant 2004118414), and in part by grants from the Fondazione Cassa di Risparmio di Pisa (Pisa, Italy) and Fondazione CARIPLO (Milano, Italy).
Received 14 February 2006; accepted 17 February 2006