A COMPREHENSIVE EVALUATION OF REINFORCER IDENTIFICATION PROCESSES FOR PERSONS WITH PROFOUND MULTIPLE HANDICAPS

We evaluated comprehensively a preference assessment for identifying reinforcers for persons with profound multiple handicaps. Four experiments were conducted involving 18 individuals. Results of Experiment 1 replicated previous findings in that the assessment identified student preferences for respective stimuli, and caregiver opinion of preferences did not coincide with the systematic assessment. Results of Experiment 2 indicated highly preferred stimuli were likely to function as reinforcers in training programs, whereas stimuli not highly preferred did not function as reinforcers. Results of Experiment 3 suggested the 12 stimuli used in the assessment represented a comprehensive stimulus set for identifying preferences, although the utility of the set sometimes could be enhanced by caregiver opinion. Results of Experiment 4 indicated the assessment identified preferences likely to be maintained over time. Overall, results are discussed in terms of identifying limits and alternatives to a behavioral teaching technology when applied to persons with profound multiple handicaps.     

Economic substitutability of electrical brain stimulation, food, and water.

Concurrent variable-ratio schedules of electrical brain stimulation, food, and water were paired in various combinations as reinforcement of rats' lever presses. Relative prices of the concurrent reinforcers were varied by changing the ratio of the response requirements on the two levers. Economic substitutability, measured by the sensitivity of response ratio to changes in relative price, was highest with brain stimulation reinforcement of presses on both levers and lowest with food reinforcement of presses on one lever and water reinforcement of presses on the other. Substitutability with brain stimulation reinforcement of presses on one lever and either food or water reinforcement for presses on the other was about as high as with brain stimulation for presses on both levers. Electrical brain stimulation for rats may thus serve as an economic substitute for two reinforcers, neither of which is substitutable for the other.     

Decreasing junk-food consumption through the use of self-management procedures: a case study

By using a self-management program, a 25-yr.-old white male was able to decrease the amount of junk food and beverage consumed while increasing the amount of healthier food and beverage ingested during evening snacks. This change was evident at 6 wk. and at a 6-mo. follow-up. Factors contributing to this success were discussed.     

Integral processing of visual place and auditory voicing information during phonetic perception.

Results of auditory speech experiments show that reaction times (RTs) for place classification in a test condition in which stimuli vary along the dimensions of both place and voicing are longer than RTs in a control condition in which stimuli vary only in place. Similar results are obtained when subjects are asked to classify the stimuli along the voicing dimension. By taking advantage of the "McGurk" effect (McGurk & MacDonald, 1976), the present study investigated whether a similar pattern of interference extends to situations in which variation along the place dimension occurs in the visual modality. The results showed that RTs for classifying phonetic features in the test condition were significantly longer than in the control condition for the place and voicing dimensions. These results indicate a mutual and symmetric interference exists in the classification of the two dimensions, even when the variation along the dimensions occurs in separate modalities.     

A computerized infrared monitor for following movement in aquatic animals

Reliable monitoring of the movement of small aquatic animals presents some unique problems. In the case of the larval salamander, the animal may be less than an inch long and move in sporadic short bursts. A device is described that utilizes infrared emitters and wide-band sensors inter-faced to a computer for monitoring location and movement of animals between light and dark environments over extended periods of time. The system employs a multiplexed digital input, is inexpensive, and can be easily expanded to deal with a range of monitoring problems that may occur with a wide range of both aquatic and terrestrial species.     

Acquisition and extended retention of a conditioned taste aversion in preweanling rats

The time course of memory decay for infant rats may shed light on the processes responsible for infantile amnesia. A taste aversion conditioning procedure appropriate for both neonatal and adult rats was employed in four experiments to investigate the ontogeny of extended retention. In Experiment 1, rats trained at 1, 10, 20, or 60 days of age were tested for retention of the taste aversion 25 days later. At testing, only those rats conditioned when 20 or 60 days old demonstrated significant taste aversions. Experiments 2 and 3 established that rats 14-15 days old and older were able to retain significant taste aversions following a 25-day retention interval. Younger rats did, however, acquire and retain the aversion for several days and showed a gradual retention loss over progressively longer retention intervals (Experiment 4). These findings suggest that preweanling rats demonstrate initial consolidation, storage, and retrieval of conditioned taste aversions. It is only after this initial period that retention deficits become evident.     

Biculturalism,Locus of Control,and Leader Behavior in Ethnically Mixed Small Groups1

The study examined the interactive effects of degree of biculturalism and locus of control on leader behavior in supportive and nonsupportive ethnically mixed small groups. Subjects were 36 male Chicano college students who participated in a small group discussion composed of four members: a naive subject who invariably served as group leader, and three confederates representing distinct ethnic groups (Anglo, Black, and Chicano). Behavioral observations revealed several interesting interactions involving group support. High biculturals, in comparison to low biculturals, adopted a more active leader role in nonsupportive than in supportive groups, asking for more opinions and evaluations, and making more clarification statements. Furthermore, while low bicultural externals and high bicultural internals tended to be more interpersonally assertive and to make more clarification statements under supportive conditions, it was low bicultural internals and high bicultural externals who exhibited the most active leader roles in nonsupportive groups. Additional findings revealed that statements made by the Anglo confederate were clarified more often in the supportive condition, while statements made by either the Black or the Chicano confederate were clarified more often in the nonsupportive condition. The results are discussed in relation to previous literature and the need to develop a more responsive social psychology of interethnic dynamics.     

Patterns of perceived similarity cannot be generalized from long to short exposure durations and vice versa

Subjects rated the perceived similarity between patterns and their 180-deg rotational variants. The stimuli, adapted from Halpern, Fishbein, and Warm (1979), were randomly generated dot patterns and line drawings and polygons generated from the dot patterns. Inspection time was varied in a between-subject design. As in the Halpern et al. (1979) study, it was found that the variables of form type (dots, lines, polygons) and axis of rotation (x, y, z) had no effect on perceived similarity in the long exposure conditions. However, when inspection time was limited to 150 msec, both variables had a substantial impact. This finding undermines the frequent practice of selecting stimuli for use in reaction time or other experiments with limited inspection time on the basis of similarity ratings gathered under typical free inspection conditions.     

Cerebral laterality and verbal-performance discrepancies in intelligence

The cerebral laterality of children with various configurations of verbal-performance discrepancies was inferred with an objective measure of lateral preference. Specifically, Verbal and Performance IQ scores of the WISC-R were used to divide 90 learning-disabled children into three equal groups: (a) Verbal significantly higher than Performance, (b) Performance significantly higher than Verbal, and (c) Verbal not significantly different from Performance. Analysis of the scores on the Laterality Preference Schedule showed children in the Verbal > Performance group were significantly more bilateral in their preference patterns than either of the other groups. Data on familial laterality showed this Verbal > Performance group to also have parents who were significantly more mixed in their preference patterns than either the VSIQ < PSIQ or VSIQ = PSIQ groups. The results were interpreted as lending support to the notion of competition antagonism between cortical hemispheres and a possible genetic relationship.