Using overt rehearsals to explain word frequency effects in free recall

Three experiments examined the word frequency effect in free recall using the overt rehearsal methodology. Experiment 1 showed that lists of exclusively high-frequency (HF) words were better recalled, were rehearsed more, and were rehearsed to more recent serial positions than low-frequency (LF) words. A small HF advantage remained even when these 2 variables were equated. Experiment 2 showed that all these effects were much reduced with mixed lists containing both HF and LF words. Experiment 3 compared pure and mixed lists in a within-subject design and confirmed the findings of Experiments 1 and 2. It is argued that number of rehearsals, recency of rehearsals, and strength of interitem associations cause the word frequency effect in free recall.     

Parental assessment and treatment of food selectivity in natural settings

This study evaluated the effects of a parent-conducted functional analysis and treatment consisting of differential reinforcement of an alternative behavior, escape extinction, and demand fading on food selectivity in a young child with autism. Increases in food acceptance at home and in a restaurant were obtained.     

Rapid assessment of the effects of restraint on self-injury and adaptive behavior

We evaluated the effects of restraint on occurrences of self-injurious behavior (SIB) and adaptive responses exhibited by 2 individuals across eight response-effort conditions: baseline (no restraints); restraint sleeves without stays; restraints with 5, 10, 15, 20, or 25 thin metal stays; and restraints with five thick metal stays. From this analysis, we identified a restraint level for each participant that reduced SIB but did not inhibit adaptive responding.     

The independence of recall and recognition in motor learning

A basic tenet of both current closed-loop theories of motor learning (Adams, 1971; Schmidt, 1975) is that the generation of response specifications during learning is required for the development of recall memory. Two experiments were performed to test this tenet by attempting to demonstrate the development of recall memory in the absence of response specification production. The task in both experiments required blindfolded subjects to learn to produce a rapid, novel criterion movement on a linear positioning device. Control subjects in both experiments actively produced movements during learning with knowledge of results (KR) while experimental subjects in Experiment 1 experienced only the endpoint locations and in Experiment 2 were passively moved to the endpoint locations. Following initial KR trials, both experimental and control groups attempted to actively produce the criterion movement in the absence of KR. The results of both experiments support closed-loop theory that active practice is required to develop recall memory. There was some suggestion, however, that passive experience with sensory feedback may also aid recall memory development, contrary to the two closed-loop theories.     

Additivity in prism adaptation as manifested in intermanual and interocular transfer

Level of adaptation was assessed in both exposed and unexposed eye and/or hand for visual shift (VS), proprioceptive shift (PS), and the eye-hand coordination, negative after effect (NA) measure of both visual and proprioceptive change, following 15-min and 20-diopter base-right displacement viewing of the active hand, under conditions of unconstrained head movement and terminal exposure feedback. Transfer was complete for the VS test, and significant, but incomplete for the PS and NA tests. For both exposed and unexposed eye/hand situations, level of adaptation was greater for the NA than for the PS test, which in turn showed greater adaptation than the VS test. Additivity was virtually perfect for the unexposed eye/hand (VS+PS = NA), but underadditivity appeared for the exposed eye/hand (VS+PS < NA). This underadditivity was approximately equal in magnitude to the amount that transfer on the NA test was less than on the PS test, suggesting that underadditivity was due to a nontransferable, assimilated corrective response in the NA test with the exposed eye/hand. Possible explanations for intermanual transfer are discussed.