Neuropsychologia 40 (2002) 1516–1522 Note Sex and spatial position effects on object location memory following intentional learning of object identities Gerianne M. Alexander a,∗ , Mark G. Packard b , Bradley S. Peterson c a Yale Child Study Center, 230 South Frontage Road, New Haven, CT 06520, USA b Yale Department of Psychology, 2 Hillhouse Avenue, New Haven, CT 06520, USA c Department of Child and Adolescent Psychiatry, New York State Psychiatric Institute, College of Physicians and Surgeons, ColumbiaUniversity, New York, NY, USA Received 20 February 2001; received in revised form 29 October 2001; accepted 29 October 2001 Abstract Memory for object location relative both to veridical center (left versus right visual hemispace) and to eccentricity (central versus peripheral objects) was measured in 26 males and 25 females using the Silverman and Eals Location Memory Task. A subset of participants (17 males and 13 females) also completed a measure of implicit learning, the mirror-tracing task. No sex differences were observed in memory for object identities. Further, in both sexes, memory for object locations was better for peripherally located objects than for centrally located objects. In contrast to these similarities in female and male task performance, females but not males showed better recovery of object locations in the right compared to the left visual hemispace. Moreover, memory for object locations in the right hemispace was associated with mirror-tracing performance in women but not in men. Together, these data suggest that the processing of object features and object identification in the left cerebral hemisphere may include processing of spatial information that may contribute to superior object location memory in females relative to males. © 2002 Elsevier Science Ltd. All rights reserved. Keywords: Human evolution; Spatial ability; Gender; Cognition 1. Introduction Sex differences in human spatial abilities are consistent with the predictions of evolutionary theory and the hypothe- sized social roles of early women and men [7,36]. If hunters were predominantly male, then it is reasoned that selec- tion pressures might contribute to spatial abilities in men that enhance the hunt and capture of animals. If gatherers were predominantly female, then similar selection pressures might contribute to a female advantage on different spatial tasks. The successful gathering of plant food, for example, may require abilities to identify the shape and color of ed- ible plants and to associate landmarks (e.g. a particular tree or rock) with their locations. The adaptive significance of sex-specific spatial abilities is consistent with the present day male advantage in spatial navigation [11,30,35] and the accurate aim of projectiles [41]. In addition, tasks developed specifically to test the novel hypothesis of a female advan- ∗ Corresponding author. Tel.: +1-203-432-4671; fax: +1-203-432-7172. E-mail address: gerianne.alexander-packard@yale.edu (G.M. Alexander). tage on other spatial tasks show that women and young girls outperform men and young boys in their memory for objects identities and their locations in a visual spatial array [7,36]. Research of visual and spatial processing suggests that these present day sex-typed spatial abilities (e.g. spatial nav- igation or locating objects in an array) may have distinct neu- ral bases that evolved from the diverse processing require- ments of hunting and gathering. The gathering of animal food through hunting involves the identification of spatial position and movement, whereas the gathering of plant food involves identification of object features, including color. In primates, the identification of objects and their locations is accomplished by two functionally and anatomically distinct pathways that ultimately project to the frontal cortex [19,38]. Object recognition and the identification of visual patterns and colors are processed through the parvocellular pathway (the “what” pathway), which proceeds ventrally from the vi- sual cortex to the inferior temporal region. Spatial locations, object movements, and global analyses of visual scenes are processed through the magnocellular pathway (the “where” pathway), which proceeds dorsally from the visual cortex to the posterior parietal cortex. 0028-3932/02/$ – see front matter © 2002 Elsevier Science Ltd. All rights reserved. PII:S0028-3932(01)00215-9