Decrease of Precurrent Behavior as Training Increases: Effects of Task Complexity

Pigeons prefer to invest early for future reinforcers

Five pigeons were trained in a series of conditions in which food was delivered after 25 responses, but only when a different (Investing) response had been made before the 25 responses had been completed. If an Investing response was not made, the 25 responses ended in blackout. In various conditions, effective Investing responses either had to be made before the first of the 25 responses, or anywhere within the 25 responses; and effective Investing responses either resulted in a stimulus change or did not. Pigeons Invested even when the consequences were temporally and spatially distant, but Investing was most likely when it produced an immediate stimulus change. When given the choice, pigeons preferred to make Investing responses at the beginning of a trial. These findings again demonstrate that behavior may be maintained by events that are separated in time and space from the present.

Effects of task complexity on learning to skip steps: an operant analysis

In most response sequences auxiliary responses stop occurring as training increases. Auxiliary responses are precurrent responses that increase the likelihood of reinforcement for subsequent responding, are not required by the programmed contingencies, and occur in situations in which transfer of stimulus control is not prevented. For example, when someone is learning to solve arithmetic problems, some steps, such as writing down intermediate calculations, are skipped as training increases. A paired-associates task was used to investigate the decrease of auxiliary response, in which participants had to learn the second member (arbitrary characters) of each pair upon being presented with the first member (different shapes), and could look up an auxiliary screen (auxiliary response) in order to do so. Task complexity was varied by changing the average programmed frequency of reinforcement for individual responses (Experiment 1) and response sequences (Experiment 3), the programmed probability of reinforcement for responses given a position (PPRPos) with a fixed (Experiment 2) or variable number of associated pairs (Experiment 4), and the programmed probability of reinforcement for responses given a shape with fixed (Experiment 5) or variable (Experiment 6) number of characters per shape. Increases in these variables produced systematic decreases in the duration of auxiliary behavior necessary to learn the task. These results suggest that some aspects of task complexity can be measured based upon the quantification of the programmed contingencies of reinforcement.