Making choice a routine part of mealtimes for persons with profound mental retardation

Despite increased recognition of the importance of providing routine choice opportunities for persons with severe handicaps, this population continues to experience a typical lack of such opportunities. We evaluated a program for increasing the amount of choices made during routine mealtimes by persons with profound mental retardation and minimal communication skills. The choice provision program, involving systematic presentation of alternative food and drink items in a step-wise fashion during the course of the meal, was implemented with three persons in a residential facility. Results indicated that after implementation of the choice program, all three participants made consistently more choices concerning the foods and beverages they consumed relative to baseline. The choice provision program was conducted without extending the amount of time typically allotted to mealtime within the residential setting. Results are discussed in regard to additional research needed to continue developing means of assisting persons with profound mental retardation to exert control over meaningful events in their lives.     

Teaching minority high school students to recruit helpers to attain personal and educational goals

Recruiting help from mentors and other potential helpers is a promising strategy for helping disadvantaged and minority youths meet their personal and educational goals. Three African-American high school seniors participated in a project designed to evaluate the effectiveness of training procedures that would allow them to ask for help in attaining educational and other personal goals. A behavioral training procedure that included instructional materials, role-play practice, praise, and feedback was used. Targeted skills included goal setting and 30 responses involved in the process of meeting with a potential helper. Role-play situations were used to evaluate participants' help-recruiting skills before and after training. Participants increased their help-recruiting skills from an average of 38% during baseline, to an average of 75% after training. Self-reported measures of goal attainment suggested that the students benefited from the training. Implications for mentoring programs designed to increase minority students' opportunities to reach educational goals were discussed.     

Microsecond resolution timing with Sun workstations

A high-resolution clock is often indispensable for the accurate measurement of millisecond or microsecond resolution intervals, and it is impossible to measure the probability distribution of short intervals without one. This paper describes a microsecond clock for Sun 3 and 4 workstations that we designed, built, and have made publicly available. It also explains how to measure intervals shorter than a computer’s clock resolution, and derives confidence intervals for such measurements.     

Personality,stress, smoking,and genetic predisposition as synergistic risk factors for cancer and coronary heart disease

Risk factors for cancer have been found in the past to act synergistically in a number of studies. However, these studies were not always designed to test the hypothesis of synergism, and have sometimes failed to equate for important variables, which might influence the results. The present study tests the hypothesis that psychosocial variables and physical ones (personality/stress, smoking, and genetic predisposition) interact in a synergistic fashion in the causation of lung cancer and coronary heart disease (CHD).     

Human classical conditioning

Recent reports of failure to obtain blocking in human galvanic skin response (GSR) conditioning, together with our own equivocal results with eyelid conditioning, have motivated us to re-examine the status of the conditioned stimulus (CS) in human conditioning studies. The issues raised by compound stimuli, by contextual cues and occasion setting stimuli, and by cross-modal transfer are considered in the light of data from our laboratories. These data include observations on the interchangeability of stimulus modalities during acquisition, the use of varying information loads embedded in occasion setting displays, the comparison of alternative blocking designs and the analysis of response topography in relation to stimulus variability. They suggested that an adequate account of the CS in human conditioning studies must recognize that it is dynamically processed and reprocessed both during and after acquisition.     

Describing parent-child interaction during exploration: situation definitions and negotiations

A coding scheme based on Wertsch's (1983) extension of Vygotsky's ideas about adult-child interaction in the zone of proximal development was used to analyze parent-child interaction during exploration. Sixty children, 3 to 6 years old, were videotaped while exploring novel objects in 15-min sessions with their mothers and fathers. Clusters of verbal and nonverbal behavior were used to code how participants defined the situation in each 15-s interval of each session in terms of one of nine categories. When parent-child mismatches occurred, the participants' negotiations of an intersubjective definition were coded, and child and parent questions were coded for complexity, complexity and appropriateness of response, and function. Results indicated that parent and child definitions matched almost 80% of the time, usually around exploration by the child with attention of or collaboration by the adult. Fathers tended to be more didactic than mothers.     

The time course of extinction-induced aggressive behavior in humans: Evidence for a stage model of extinction

Three experiments examined the effects of extinction on aggressive responding in male college students. In Experiment 1 subjects initially performed on a task where shuttle responding was either continuously or partially reinforced with tokens while either a nonaggressive button-pressing response or an aggressive pad-striking response was concurrently reinforced by escape from a moderately aversive tone. During shuttle acquisition there was clear preference for the escape response of button pressing, but when shuttle responding was extinguished subjects began to respond aggressively by striking the pad to escape. The time course of aggressive escape responses during concurrent shuttle extinction was an inverted U; aggressive responding rose to a peak and then declined. Aggressive responding began earlier in extinction following continuous- as contrasted with partial-reinforcement shuttle training. Experiment 2 showed that similar extinction-induced aggression was precipitated by both moderate and extended continuous-reinforcement shuttle training, with earlier onset after extended reinforcement. Experiment 3 ruled out the possibility that the emergence of the pad-striking response during extinction was simply induced response variation. These data were interpreted within the theoretical framework of P.T.P. Wong's recently advanced stage model of extinction (Animal Learning and Behavior, 1978,6, 82–93).     

Sensory superstition on multiple interval schedules.

Pigeons were exposed to multiple schedules in which an irregular repeating sequence of five stimulus components was correlated with the same reinforcement schedule throughout. Stable, idiosyncratic, response-rate differences developed across components. Components were rank-ordered by response rate; an approximately linear relation was found between rank order and the deviation of mean response rate from the overall mean rate. Nonzero slopes of this line were found for multiple fixed-interval and variable-time schedules and for multiple variable-interval schedules both when number of reinforcements was the same in all components and when it varied. The steepest function slopes were found in the variable schedules with relatively long interfood intervals and relatively short component durations. When just one stimulus was correlated with all components of a multiple variable-interval schedule, the slope of the line was close to zero. The results suggest that food-rate differences may be induced initially by different reactions to the stimuli and subsequently maintained by food.     

Interval and ratio reinforcement of a complex sequential operant in pigeons

Pigeons were required to produce exactly four pecks on each of two keys in any order for reinforcement. Correct response sequences were reinforced on either fixed-interval two-minute or fixed-ratio four schedules, with each correct sequence treated as a single response. Each pigeon developed a particular dominant sequence that accounted for more than 80% of all sequences. Sequence stereotypy was relatively unaffected by the temporal properties of the fixed-interval and fixed-ratio schedules. Response time (time from the first response in each sequence to the last) was also relatively unaffected by the temporal properties of the schedules. In contrast, response latency (time from end of one sequence to the beginning of the next) was markedly affected by the schedules. Latencies were long early in the interreinforcement interval and got shorter as the interreinforcement interval progressed. These data suggest that stereotyped response sequences become functional behavioral units, resistant to disruption or alteration by reinforcement variables that ordinarily influence the temporal spacing of individual responses.