Visual Memory for Shapes in Deaf Signers and Nonsigners and in Hearing Signers and Nonsigners: Atypical Lateralization and Enhancement Allegra Cattani, John Clibbens, and Timothy J. Perfect University of Plymouth Deaf and hearing individuals who either used sign language (signers) or not (nonsigners) were tested on visual memory for objects and shapes that were difficult to describe verbally with a same/different matching paradigm. The use of 4 groups was designed to permit a separation of effects related to sign language use (signers vs. nonsigners) and effects related to auditory deprivation (deaf vs. hearing). Forty deaf native signers and nonsigners and 51 hearing signers and nonsigners participated in the study. Signing individuals (both deaf and hearing) were more accurate than nonsigning individuals (deaf and hearing) at memorizing shapes. For the shape memory task but not the object task, deaf signers and nonsigners displayed right hemisphere (RH) advantage over the left hemisphere (LH). Conversely, both hearing groups displayed a memory advantage for shapes in the LH over the RH. Results indicate that enhanced memory performance for shapes in signers (deaf and hearing) stems from the visual skills acquired through sign language use and that deafness, irrespective of language background, leads to the use of a visually based strategy for memory of difficult-to-describe items. Keywords: deaf nonsigners, deaf signers, hearing signers, laterality, visual memory Supplemental materials: http://dx.doi.org/10.1037/0894-4105.21.1.114.supp Anecdotal accounts by hearing adult students taking sign lan- guage (SL) courses have indicated that the experience of learning SL places great demands on visuospatial memory. For example, one training exercise in use (Smith, Lentz, & Mikos, 1988) in- volves the memorization of the composition of four or five build- ing blocks of different shapes and colors. The SL teacher shows this composition for a short time (1–2 s), and then the task is to reproduce it by choosing the correct pieces from a basket contain- ing other blocks of several shapes and colors. The anecdotal evidence has suggested that deaf signers possess better visuospa- tial memory, although it is not clear whether this is due to altered sensory experience or to altered language experience stemming from early acquisition of a visuospatial language: the SL spoken by the deaf community. Experiential factors have significant influence on the devel- opment of the visual system. Different parts of the visual system appear to be sensitive to different aspects of environ- mental input and as such are likely to have different develop- mental trajectories (Bavelier & Neville, 2002; Proksch & Bave- lier, 2002). Developmental changes could be due to auditory deprivation (AD). In that sense, AD seems to have a large impact on spatial processing. More specifically, deaf individu- als have shown enhanced spatial skills in peripheral vision but not in central vision when compared with hearing populations (Bavelier et al., 2001; Bavelier & Neville, 2002; Bavelier et al., 2000; Neville & Lawson, 1987a, 1987b, 1987c; Parasnis & Samar, 1985; Proksch & Bavelier, 2002). Findings from these studies that involved the detection of the onset of a stimulus, the direction of motion, and the ability to switch visual attention toward a target indicated that visual perception in the peripheral field of deaf signers as opposed to hearing signers and nonsign- ers may be enhanced because of their AD. The visual compen- sation because of AD is likely to improve perceptual spatial processes involving parafoveal detection tasks and the spatial distribution of visual attention in peripheral fields. Therefore, in the absence of the auditory modality to orient toward extraper- sonal space, deaf individuals must rely more heavily on mon- itoring peripheral visual space to detect new information in their environment. SL use seems to affect performance on visual processing. It has been postulated that SL use does not create a general enhancement of visual cognitive processes. Rather, it appears to have a selective effect on certain processes that may be involved in SL production and comprehension such as face discrimination and mental rota- tion of images (Chamberlain & Mayberry, 1994; Emmorey, Kosslyn, & Bellugi, 1993; see also Emmorey, 2002, for a review). Evidence further has suggested that SL use affects memory for particular kinds of items. Arnold and Mills (2001) reported that SL Allegra Cattani and John Clibbens, School of Applied Psychosocial Studies, University of Plymouth; Timothy J. Perfect, School of Psychol- ogy, University of Plymouth. This research was supported by Marie Curie Fellowship HPMF-CT- 2000-000651 from the European Community program to Allegra Cattani. Special thanks go to those who volunteered in this study. We thank many Italian and British people who contributed to the realization of this re- search. From the British side, we thank Plymouth and Torquay Deaf Clubs, national and local sites (Plymouth, Bristol, and Cardiff) of the Royal National Institute for the Deaf, Bristol and City Universities, British Deaf Association, Plymouth Hearing and Sight Center, and Plymouth City Council. From the Italian side, we thank the National Council for Research, the Institute for the Deaf located in Rome, and Ente Nazionale Sordomuti located in Genoa and Palermo. Laura Gian Greco Marotta, Maria Teresa Ferrisi, and Caterina Bagnara helped enormously in recruitment of partic- ipants. Thanks also to Mike Tucker for the development of the experimen- tal software. Correspondence concerning this article should be addressed to Allegra Cattani, School of Applied Psychosocial Studies, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom. E-mail: a.cattani@ plymouth.ac.uk CORRECTED MAY 4, 2007; SEE LAST PAGE Neuropsychology Copyright 2007 by the American Psychological Association 2007, Vol. 21, No. 1, 114 –121 0894-4105/07/$12.00 DOI: 10.1037/0894-4105.21.1.114 114 This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.