The effects of proactive and retroactive demonstrations on learning signedletters

Four groups of adults learned letters of the American manual alphabet with augmented information (demonstrations) provided by a model. The model was p resented either before (proactive) or after (retroactive) attempted perform ances of the letter handshapes, thereby providing different learning contex ts. Acquisition performance was enhanced when the demonstrations were prese nted immediately prior to performance, and degraded when the demonstrations followed performance. Same day and delayed (48 h) retention tests without augmented information revealed a large drop in performance for the proactiv e groups and a slight improvement in performance for the retroactive groups . These findings are compared to related effects which suggest that augment ed information has both negative and positive influences on learning. (C) 1 999 Elsevier Science B.V. All rights reserved.