Maintenance of signal directed behavior in a response dependent paradigm: a systems approach.

Rats were trained in a straight alley to repeatedly press a bar placed at one end of the alley until a discriminative signal (SD) appeared and to run for water reward (Rd) available at the other end. During training SD was spatially contiguous with Rd, then SD was placed above the bar (spatially discontiguous with Rd). In Experiment I subjects were trained for ten days, in Experiment II to equal level of performance before cue rearrangement. Experiment III applied systems analysis. Making SD spatially discontiguous with Rd caused abrupt and characteristic changes in many of the parameters observed (e.g., start-time, bar press perseveration, bar press topography, rearing, intertribal runs, defecation). If rats were initially trained under SD -Rd spatial discontiguity condition, making SD spatially contiguous with reward did not deteriorate their performance. It was concluded that: (i) rats learn and maintain responding to informative signals also in response dependent paradigms, (ii) spatial location of cue is of substantial importance for animals, and cue rearrangement will necessarily modify the topography of the learned response, (iii) the findings exclude the adventitious reinforcement explanation of signal directed behaviors, and question the validity of the concept of equivalent associability.