A comparison of multiple versus single examples of the correct stimulus on task acquisition and generalization by persons with developmental disabilities

In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.     

On the validity of scalp recordings of the auditory evoked potential

Simultaneous recording from scalp and cortical electrodes in unanesthetized and unrestrained cats revealed essentially no differences between the superficial and deep recordings of the auditory evoked responses. Human recordings taken under two conditions of muscular contraction contained no major differences from 30 to 300 msec after stimulus onset.     

Student Political Campaigners: Who Campaigns and What Effect Does It Have on Them?

What characterizes students who become involved in political campaigns and what effects does their campaigning have on them? During a 2-week election recess, about one-third of the students at Princeton University chose to campaign. Those students who did so were liberal rather than radical in their political orientation. Those who participated seemed predisposed to campaign because they thought campaigning was an effective way of bringing about the changes that they sought. Campaigners were more likely than their fellow students to have engaged in political activity before. Such efforts may be evidence of their beliefs that political activity causes change, or might have been the forming experience for those beliefs. If the candidate for whom the student campaigned won the election, the student by and large strengthened or maintained his original attitudes about the efficacy of campaigning. If his candidate lost, the student became more pessimistic about the efficacy of campaigners whose candidates won also changed in an internal direction on a personal-control subscale of Rotter's (1966) internal-external scale; those whose candidates lost tended to change in an external direction.     

Facilitation and suppression of human loss-avoidance by signaled, unavoidable loss

A 15-sec stimulus followed by unavoidable monetary loss was presented to human subjects who were avoiding loss on a free-operant schedule. As has been observed in studies where shock is the aversive event, initial reactions to the pre-loss stimulus were transient increases in overall and stimulus rates. Unlike shock studies, continued training produced decreased rates, in the presence of the 15-sec stimulus, which were maintained in two of three subjects. Subsequent observations indicated that lowered rates were a function of the subject's rate of avoidance responding, the duration of the stimulus, and the scheduling of avoidable losses. Increasing the duration of the stimulus eliminated lowered rates in the presence of the stimulus and subsequent exposures to conditions which previously produced lowered rates did not result in recovery of the phenomenon. Introduction of the pre-loss stimulus on an extinction baseline (avoidable losses were omitted), however, reinstituted lowered rates. It is proposed that the pre-loss stimulus assumed discriminative control over low rates because responding in the presence of the stimulus was ineffective in avoiding the unavoidable loss. Recovery from lowered rates is attributed to the occurrence of avoidable losses during the stimulus period, and maintenance of lowered rates on the extinction schedule to the omission of such avoidable losses.     

Self-concept in educable mentally retarded and emotionally handicapped children

A total of 48 educable mentally retarded (EMR) and emotionally handicapped (EH) children ( \(\overline {CA} \) =137.7 months) were pretested on Coopersmith's Self-Esteem Inventory (SEI), Nowicki-Strickland's Locus of Control Scale for Children (LCSC), and 3 behavioral measures: (1) risk-taking, (2) a chance/skill task, and (3) delay of gratification. One group of 12 children from each population was then exposed to either a self-confident or a control model. After exposure, Ss were given an opportunity to perform successfully on an ambiguous task and answer questions about their success, and were readministered the SEI, LCSC, and 3 behavioral choices. Correlational analyses of pretreatment data revealed significant relationships between defensiveness and LCSC, SEI, and delay of gratification and a near-significant relationship between LCSC and SEI. EMR and EH Ss were both lower on self-esteem than the general population, while EMR Ss were more defensive, more external, and less likely to delay gratification than EH Ss. Both treated groups matched more of the behavioral choices than the control groups, while only treated EH Ss were more likely to attribute their success to internal causes. It was concluded that EMR and EH children differ in self-concept development and that future attempts to modify self-concept should include greater modeling exposure as well as increased opportunity for performance with its resultant feedback.     

The quantitative measure of pattern representation in images using orientation-specific color aftereffects

A quantitative method is developed for assessing the quality of pattern information in imagery, using the magnitude of color aftereffects as an objective index. Subjects were given instructions to project imagined bar patterns of particular width and orientation onto adapting color fields, in such a manner as to simulate standard conditions for establishing the McCollough effect. Our control procedures indicate that the resulting orientation-specific complementary color aftereffects cannot be attributed to the conditioning of particular directions of eye scanning movements to color processing during adaptation, or to other possible sources of experimental bias. Furthermore, subjects who rated themselves prior to the adaptation procedure as having relatively vivid imagery showed significantly larger aftereffects than those who reported having relatively low imagery. These results not only provide an important confirmation of our earlier finding that imagination can replace physical pattern information in the formation of basic color-feature associations in the human visual system, but also demonstrate that these aftereffects can provide a practical measure of the fidelity of pattern representation in visual images.