Indexador

Rats were trained in shock‐induced aggression, free operant avoidance, or were presented with unavoidable shocks. Fighting in response to shock was subsequently measured by intermatching individual animals that had received the three training procedures. The fighting probabilities of animals with histories of avoidance and dominant animals with histories of fighting were higher than the fighting probabilities of non‐dominant fighting rats or rats with a history of unavoidable shocks. Animals with higher fighting probabilities disrupted avoidance baselines more than animals with lower fighting probabilities. Control experiments suggested that fighting decrements produced by administration of prior grid‐shock were due to the acquisition of behaviors incompatible with aggression.

Several studies have shown that behavior modification procedures aimed at a single behavior may have effects on other, nonmanipulated behaviors. A young retarded boy engaged in excessive conversation with his preschool teacher. The teacher then began to ignore his initiated conversation during free‐play periods, and it decreased. In addition, (1) social behavior relative to children increased, and (2) use of girls' toys decreased during free play. Also, (3) appropriate behavior at group academics declined, while (4) disruptions rose. In a second study, the teacher alternated conditions of praise and ignoring for talking with children. Talking with children varied accordingly. In addition, use of girls' toys and group academics disruptions rose during the ignoring condition. Appropriate behaviors dropped. Lastly, a timeout procedure was used to eliminate the undesirable side effects of disruptions and of use of girls' toys. Apparently, a response class may have member behaviors that covary directly and/or inversely. Some covariations may be socially desirable, others undesirable. The appearance of undesirable “side effects” can be controlled using behavior modification techniques.

The effects of changing signal frequency on a prolonged vigilance task were investigated by systematically increasing the average inter‐trial interval between successive signals. During a 6‐hr watch, vigilance performance remained constant when the rate of signal presentation was 40, 20, and 10 per hour. When the rate of signal presentation was reduced to 7 or 4 per hour, marked decrements in detection performance were observed. Similar vigilance decrements occurred when the average rate of signals per hour was kept constant (10 per hour) and the probability of receiving a shock for missing a signal was systematically varied. The results of this study indicate the importance of reinforcement factors in the control and maintenance of vigilance performance.

Pigeons' responses were reinforced on two identical and concurrently available chain variable‐interval‐schedules. Unlike the typical concurrent chains procedure, both links were operative throughout, thus producing three types of concurrency: (1) concurrent initial links; (2) concurrent initial and terminal links; (3) concurrent terminal links. Choice proportions in each of these three states suggested that the pigeons were sensitive to momentary likelihoods of reinforcement: choice proportions for a schedule were higher when the schedule had been operative for some time, resulting in a higher probability of reinforcement. The study also showed that the relative rates of responding did not match the relative rates of reinforcement in any of the three states of concurrency. Instead, the choice proportions in both the concurrent initial and in the concurrent terminal links were intermediate between the scheduled and the obtained relative rates of reinforcement, while the choice proportions for a terminal link concurrent with an initial link consistently overmatched the relative interreinforcement times (and were typically 1.00). These data indicate that an accurate characterization of choice may not be obtained by considering only the relative interreinforcement interval where one interreinforcement interval is segmented into a chain. Instead, the organism's choice for a schedule will be substantially lowered by the chaining operation.

Animals permitted free access to a running wheel and drinking tube increased the amount of running when drinking was punished with electric shock. Additional experiments demonstrated that the simple presence or absence of a drinking tube (or running wheel) was a sufficient condition to observe a decrease or an increase in the alternative response. A quantitative analysis of these interactions observed between the incompatible running and drinking responses suggested that each response occupied a constant proportion of the time available for it. These results question an interpretation of the increase in unpunished alternative responding based upon its avoidance properties.

Two experiments studied the effects of brief response‐dependent clock stimuli in fixed‐interval schedules of reinforcement. In the first experiment, two pigeons were exposed to a fixed‐interval schedule. Two conditions were compared. In both conditions each peck on the key produced a brief stimulus. In one condition, pecks produced a different stimulus in successive sixths of the interval. This was the clock condition. In the other condition, the same stimulus was produced throughout the interval. Response rates were lower and the pause after reinforcement was longer in the clock condition. In the second experiment, a two‐key optional clock procedure was used. Responding on the clock key produced one of three stimuli correlated with the three successive minutes of a fixed‐interval schedule. A response on the other key produced grain at the end of the 3 min. When the final stimulus was removed from the situation and pecking produced nothing during the third minute, responding to the clock key declined to a very low rate. When the first two stimuli were removed and the third one replaced, responding to the clock key was resumed.

Language deficient, autistic children were trained to use the prepositions “in” and “on”. Three subjects were exposed to conditions of training that differed in the method of employment of stimulus objects used to train prepositional usage. Two subjects were trained first with “ambiguous” stimuli, that is, the same stimulus objects were used for training both prepositions. The two subjects were then switched to a training condition with “non‐ambiguous” stimulus objects, that is, objects used for training “in” were different than those used for training “on”. The two subjects were then switched to the ambiguous stimulus condition and finally returned again to training with non‐ambiguous stimuli (four conditions). A third subject began with training on non‐ambiguous stimuli, was switched to an ambiguous condition and was then switched back to non‐ambiguous stimuli (three conditions). The results for two of the three subjects indicated that accurate usage of the two prepositions was obtained only under training conditions with non‐ambiguous stimuli. Results for the third subject suggested that initial training with non‐ambiguous stimuli might enhance subsequent accurate responding with ambiguous stimuli.

Resumo não informado pela fonte indexada.

Children were exposed to a multiple schedule involving equal variable‐interval schedules in each of two components and a multiple schedule involving a variable‐interval schedule in one component and an extinction schedule in the other. Response rates were equal in both components when each involved a variable‐interval schedule. Response rates differed in the two components of the multiple variable‐interval extinction schedule. Response rates were higher in the variable‐interval schedule when the accompanying schedule was extinction than when it was variable interval. The increase in response rate in the variable‐interval component, simultaneous with the decrease in response rate in the extinction component, illustrated sustained behavioral contrast, and was the first evidence of this phenomenon in children.

Resumo não informado pela fonte indexada.