ABSTRACT
Decidir si una secuencia de respuestas es una unidad conductual diferente a los elementos que la constituyen y que obedece a las mismas reglas de reforzamiento que respuestas discretas ha representado un problema difícil de resolver. Una forma de mostrar que una secuencia es una unidad de conducta, es observar si dicha secuencia cumple la relación propuesta por la ley de igualación. Con este propósito, se entrenó a cuatro ratas privadas de alimento y experimentalmente ingenuas a apretar en secuencia dos operandos para recibir una gota de leche. Se usaron diferentes programas concurrentes de intervalo variable (VI) para reforzar cada una de cuatro posibles secuencias. Cuando las ratas produjeron una secuencia no reforzada, las luces de la cámara experimental se apagaron durante 2 s. En tres diferentes fases se varió la tasa de reforzamiento para cada secuencia. Los resultados mostraron que las ratas fueron altamente sensibles a las tasas relativas de reforzamiento. Sin embargo, las pendientes de las curvas de ajuste fueron menores a uno, mostrando sub-igualación. Se concluyó que una secuencia de respuestas puede comportarse como un patrón integrado pero no representa una unidad conductual estrictamente equivalente a las operantes discretas.
Deciding both, whether a response sequence is a different behavioral unit than the elements that constitute it, and if it obeys the same reinforcement rules than discrete responses, has been a difficult problem. A way to prove that a sequence is a behavioral unit is to determine if it behaves according to the principles of the matching law. With this purpose, four naïve experimentally rats were food-deprived and trained to lever press two operanda in a sequence to receive a drop of milk. Different concurrent variable interval (VI) schedules were used to reinforce each of four possible sequences. When the rats produced a non-reinforced sequence the lights of the experimental chamber were turned off during 2 s. In three consecutive phases of the experiment, the reinforcement rate for each sequence was different. Results showed that the rats were highly sensitive to the relative rates of reinforcement assigned to each sequence. However, the adjustment curves showed slopes that were smaller than one, thus under-matching was found. It was concluded that although a response sequence can behave as an integrated pattern of behavior, it does not necessarily represent an equivalent behavioral unit comparable to that of a discrete operant response.
ABSTRACT
Two experiments with rats examined the dynamics of well-learned response sequences when reinforcement contingencies were changed. Both experiments contained four phases, each of which reinforced a 2-response sequence of lever presses until responding was stable. The contingencies then were shifted to a new reinforced sequence until responding was again stable. Extinction-induced resurgence of previously reinforced, and then extinguished, heterogeneous response sequences was observed in all subjects in both experiments. These sequences were demonstrated to be integrated behavioral units, controlled by processes acting at the level of the entire sequence. Response-level processes were also simultaneously operative. Errors in sequence production were strongly influenced by the terminal, not the initial, response in the currently reinforced sequence, but not by the previously reinforced sequence. These studies demonstrate that sequence-level and response-level processes can operate simultaneously in integrated behavioral units. Resurgence and the development of integrated behavioral units may be dissociated; thus the observation of one does not necessarily imply the other.
