Reinforcer Efficacy, Response Persistence, and Delay of Reinforcement / Eficacia del reforzador, persistencia de la respuesta y demora de reforzamiento

In an evaluation of the effects of delayed reinforcement on response persistence, two pigeons were exposed to a series of conditions in which reinforcement that either immediately followed or was delayed from the response that produced it alternated across blocks of sessions. Responding was maintained by a progressive-ratio schedule in which the response requirements incremented for successive reinforcers. The effects of signaled and unsignaled delay values of 1, 5, 10, and 20 s were investigated. In general, responding was more persistent, as measured as the point at which responding ceased for 300 s, with shorter delays, regardless of whether the delays were correlated with a distinct stimulus (that is signaled) or not. The results complement earlier findings showing that reinforcement delays affect reinforcer efficacy or response persistence by showing similar effects using an index of response strength that is independent of response rate. They also extend the general effects of delay of reinforcement to a schedule in which they previously have not been demonstrated.

En una evaluación de los efectos de la demora de reforzamiento sobre la persistencia de la respuesta, se expuso a dos palomas a una serie de condiciones en las que el reforzamiento, que ya sea siguió inmediatamente a la respuesta o estuvo demorado de la respuesta que lo produjo, alternó a través de bloques de sesiones. La respuesta se mantuvo mediante un programa de razón progresivo en el que los requisitos de respuesta aumentaron para reforzadores sucesivos. Se investigaron los efectos de demoras señaladas y no señaladas de 1, 5, 10 y 20 s. En general, el responder fue más persistente, medido como el punto en el que cesó durante 300 s, con las demoras cortas, independientemente de si las demoras estuvieron correlacionadas con un estímulo distintivo (es decir demora señalada) o no. Los resultados complementan hallazgos previos que mostraron que las demoras de reforzamiento afectan la eficiencia del reforzador o la persistencia de la respuesta, al mostrar efectos similares utilizando un índice de la fuerza de la respuesta que es independiente de la tasa de respuesta. También extienden la generalidad del efecto de la demora de reforzamiento a programas en los que previamente no se había demostrado.

Efeitos paramétricos do atraso de reforço sobre o responder de ratos submetidos a esquemas de razão e intervalos variáveis / Parametrical effects on delayed reinforcement on the responding of rats exposed to variable interval and variable ratio schedules

Foram investigados os efeitos produzidos pela introdução de diferentes valores de atraso do reforço sobre as respostas de pressão à barra emitidas por oito ratos expostos a esquemas de intervalo e razão variáveis (VI e VR, respectivamente). A partir das condições de linha de base sob reforçamento imediato, aplicou-se o atraso do reforço não sinalizado e não reiniciável pelo tempo máximo programado de 1 s, 5 s e 8 s a cada um dos esquemas, em diferentes condições, em ordem crescente e decrescente de atraso. Os resultados mostraram correlação negativa entre taxas de respostas e valores do atraso do reforço para praticamente todos os sujeitos experimentais, em todos os valores de atraso. Por meio da análise dos atrasos efetivamente obtidos na sessão, foi possível constatar que a distribuição de frequência dos atrasos, independentemente do esquema em vigor, VI ou VR, concentraram-se em 0,5 s, quando o atraso programado era de 2 s. Diferentemente, foram próximos de 5 s e 8 s quando os atrasos programados foram de 5 s e 8 s, respectivamente. Esses efeitos diferenciados do atraso sobre o responder podem ser compreendidos mediante uma análise das alterações produzidas pelo atraso nas contingências específicas de cada esquema.

This study examined the effects of introducing different delays of reinforcement on the rate of leverpressing by eight rats under variable interval and variable ratio schedules (VI and VR, respectively). Following baseline conditions under immediate reinforcement, unsignaled and non-resetting delays of reinforcement were introduced upon each of these schedules. In different conditions, delays of 2 s, 5 s and 8 s were presented in both increasing and decreasing sequences. The results showed negative correlations between rate of responding and delay of reinforcement for most subjects and delays. By analyzing the frequency distribution of the delays actually obtained in each single reinforcer delivery, it was possible to verify a higher concentration of 0.5-s delays when a 2-s delay was programmed. Incontrast, actual delays concentrated around 5 s and 8 s when the programmed delays were 5 s and 8 s,respectively. Such differential effects generated by the delays of reinforcement on responding can beunderstood by analyzing how the delay affected the ongoing contingencies in each particular schedule.

Adquisición del responder bajo condiciones de reforzamiento demorado en programas temporales señalados / Response acquisition under signaled delay of reinforcement in temporally defined schedules

El estudio se diseñó con el propósito de evaluar los efectos de diferentes duraciones de demora de reforzamiento sobre la adquisición de la respuesta de presión de la palanca en ratas, empleando un programa definido temporalmente señalado. Manteniendo un ciclo T constante (64 s), para cada tres ratas se empleó una duración de demora de reforzamiento (8,24 y 56 s) que resultó de variar la posición temporal del subciclo Td al interior del ciclo T (intervalo Td-T). Se encontraron tasas de respuesta que variaron sistemáticamente en función de la duración del intervalo de demora. Los resultados se discuten atendiendo a la tasa de respuesta y a la efectividad del responder como medidas de adquisición.

A temporally defined schedule of delayed reinforcement was used to establish lever pressing by rats. A constant 8 s Td subinterval was introduced at different temporal locations into reinforcement cycle (64 s). The first response during Td produced reinforcement at the end of the cycle. Varying the temporal location of Td generated reinforcement delays of either 8 s, 24 s or 56 s. Three rats each were assigned to different delay duration. Response rates were considerably lower when Td was at the beginning of the cycle (56 s) than when the opportunity to respond was at the middle (24 s) and its end (8 s). The results are discussed focusing in the response rates and the convenience of responses per reinforcement proportion as an effectiveness acquisition measure.