Repetition and Alternation in Rats

An experiment is reported in which rats were forced equally often to each arm of a T-maze, and, following each forced trial, were given a free trial. Group R were rewarded for repeating (i.e. choosing the side to which they had just been forced), group A for alternating. All rats began by alternating, but group R eventually learned to repeat. Various delays between free and forced trials were introduced, and the forgetting curve was found to be similar for the two groups. It is argued that these results show: (i) The decline in alternation with delay found in experiments on spontaneous and rewarded alternation is due to loss of information rather than a decline in the alternation tendency. (ii) The trace involved is sufficiently general to be regarded as a memory trace. The fact that rats can learn to repeat is inconsistent with the accounts of the memory trace suggested by the theories of Deutsch and Walker.

Problem-Solving Assembly of Separately Acquired Behavior Segments: Negative Results

The experimental design was a modification of Hull's reasoning paradigm. Ss were given one forced trial per day in each of four runway segments. The trials to food, routes A-C and B-C, always preceded those to water, routes A-B and A-D. After 20 days of training under 22-hr. food and water deprivation Ss were placed under a “pure” hunger drive and given free choices between the A-B and A-D segments. The results required acceptance of the null hypothesis and thus failed to support the experimental hypothesis that rats are capable of the problem-solving assembly of separately acquired behavior segments.