COMPARISON OF CROSS-FIELD MATCHING AND FORCED-CHOICE IDENTIFICATION IN HEMISPATIAL NEGLECT

The ability of patients with neglect to process information in the con tralateral field was examined by comparing performance on a cross-fiel d matching and a forced-choice identification task. The matching task required participants to judge whether 2 laterally presented pictures were the same or different. The identification task required selection of 1 of 2 centrally presented pictures that were identical to a later alized target. As a group, neglect patients performed at chance on the identification task but significantly above chance on the cross-field matching task. However, the dissociation between matching and identif ication was present only for patients whose identification performance was at chance; patients with above-chance identification performed eq ually well on both tasks. Mechanisms underlying the matching and ident ification performance of both patient subgroups are discussed in light of procedural differences between the tasks.