Choice reaction times for skilled responses

Two kinds of choice reaction time experiments are reported, both of which make use of a highly overlearned sensori-motor response. When a response is required for each stimulus presented, no increase in reaction time occurs as a function of the number of alternative stimuli available. It is proposed that the increase in choice reaction times commonly thought to accompany an increase in the number of alternative choices provided reflects the unpractised state of the responder. When a response is required for only one out of n possible stimuli, a slight but consistent increase in reaction time takes place with an increase in the number of alternatives. An analogy is drawn between the second experiment and a vigilance task and an expectancy hypothesis is invoked to explain the results.     

Reasoning in the hooded rat

A problem situation was devised to test Deutsch's (1956) theory of reasoning. In this situation various problems can be set the rat and these problems admit of various equally rational solutions. Predictions from the theory were made, not only that the animals would solve the problems, but also which particular solution they would adopt. These predictions are confirmed. The rats were trained to run to two goal-boxes, one near, the other more distant. The near one had two paths of equal length leading to it, the more distant goal only one. After training, the animals chose the near goal-box on the first trial of the day. On the test trials the near goal-box was left empty, or the chosen path blocked, or a mesh placed across the goal-box, with the food accessible via the other short path.