Effects of reinforced directed rehearsal on expressive sign language learning by persons with mental retardation

This study used a multielement design to compare standard training (prompting and reinforcement) with and without reinforced directed rehearsal as a correction procedure in teaching expressive sign language to 10 nonverbal students with moderate to severe mental retardation. Standard training consisted of either sequential prompting or graduated guidance and 5 students were randomly assigned to each condition. Directed rehearsal involved 10 practices of the correct sign contingent on an error or no response; praise was given during directed rehearsal for cooperation and attempted signing. A stimulus control analysis revealed that only 6 of the 10 students (3 from each standard training condition) completely discriminated the trained signs within the maximum training period of 160 trials (3 of the 4 students who failed the stimulus control test were hearing impaired; the remaining 6 who showed stimulus control were not). Using only these six students' data, we found that directed rehearsal increased: (a) accuracy (percent correct), (b) speed of learning (required fewer trials to criterion), (c) efficiency (decreased total instruction time), and (d) generalization (across trainers, objects, and settings). There were no obvious interactions between directed rehearsal and the type of prompting strategy employed. Very little agitated behavior occurred in any of the sessions, and a treatment acceptability survey indicated that 10 of 14 direct-care staff and the trainers in this study preferred corrective directed rehearsal (as used in this study) over standard training alone. The results indicate that directed rehearsal may be a valuable adjunct to sign language training with nonverbal students with mental retardation.     

The contribution of morphology to word recognition

Summary Evidence of morphological processing was investigated in three word recognition tasks. In the first study, phonological ambiguity of the base morpheme in morphologically complex words of Serbo-Croatian was exploited in order to evaluate the claim that the base morpheme serves as the unit by which entries in the lexicon are accessed. An interaction of base morpheme ambiguity and affix characteristics was obtained and this outcome was interpreted as evidence that all morphological constituents of a word participate in lexical access. In the second study, facilitation due to morphological relatedness of prime and target was observed with Serbo-Croatian materials in the lexical decision and naming versions of the repetition priming task and results were interpreted as evidence of a morphological principle of organization among wholeword forms in the lexicon. In the third study, morphological affixes of both English and Serbo-Croatian words were segmented from a source word and affixed to a target word more rapidly than phonemically matched controls. Results suggest that the morphological constituents of complex words are available in some word recognition tasks and that morphological knowledge is represented in the speaker's lexicon.     

Integration of form across saccadic eye movements.

To perceive a stable world, one must somehow be able to relate visual information from successive fixations. Little is known, however, about the nature of the integrative process. By using a task which requires the integration of spatial position information from different fixations, it is demonstrated that visual information from previous fixations is preserved in a world-centered representation which is precise enough to support judgements of geometric shape. It is also shown that successive views are aligned with respect to common visual features, indicating that visual stability may be normally accomplished by a visual matching strategy in combination with cancellation by an eye-position signal.     

Primacy effects in self-attribution of ability1

Primacy effects in self-attribution of ability were investigated in an experiment. Subjects' performance on a 30-item test was experimentally manipulated to reflect one of three patterns: ascending, descending, or random success. It was predicted that there would be a primacy effect in self-attribution of ability regarding the task when subjects had no previous expectation or anchor to which performance could be assimilated, but that the primacy effect would be attenuated when a previous anchor existed. The presence or absence of a prior anchor was manipulated by describing the task as either a test related to intelligence or a test of an unsual ability, unrelated to previous experience. Results supported the hypothesis that there is a primacy effect in self-attribution of ability, and that this effect occurs most strongly where an individual has no prior anchor or expectation regarding his ability.     

Taste familiarity and apomorphine-induced taste aversions in humans

Human volunteers learned taste aversions to a relatively novel cranberry flavor paired with apomorphine-induced illness. These aversions were significantly reduced by pretreatment familiarization to the flavor unless an unpalatable interfering flavor was introduced just prior to the administration of apomorphine. The outcomes have implications for taste-aversion learning in humans and for the control of flavor preferences in patients undergoing illness-inducing chemotherapy.     

The alleviation of short-term retention decrements with reactivation

Retention of spatial information by rats was shown to decrease significantly over a 90-sec retention interval. However, this decrement was alleviated significantly when a reactivation or cueing treatment was presented during the 90-sec interval. Further, the rate of forgetting following reactivation was shown to be similar to that which occurs following original information input. The implications of these findings for information loss models of forgetting were discussed.