Prior stimulation and the perception of causality

An attempt was made to discover whether, in conditions similar to those of Michotte, the number of causal responses given by subjects was influenced by stimulation during the period just before the main experiment. Time-intervals between the arrival of object A and the departure of object B were systematically varied within the range 60 to 390 msec. Those who had earlier been exposed to shorter time-intervals (60 to 210 msec.) gave fewer causal responses than those who had been exposed to longer ones (150 to 300 msec. and 240 to 390 msec.). A possible explanation is offered in terms of the modification of existing “schemata.”     

Generalization gradients of inhibition following auditory discrimination learning

A more direct method than the usual ones for obtaining inhibitory gradients requires that the dimension of the nonreinforced stimulus selected for testing be orthogonal to the dimensions of the reinforced stimulus. In that case, the test points along the inhibitory gradient are equally distant from the reinforced stimulus. An attempt was made to realize this condition by obtaining inhibitory gradients along the frequency dimension of a pure tone after discrimination training in which the nonreinforced stimulus was a pure tone (or tones), and the reinforced stimulus was either white noise or the absence of a tone. The results showed that some degree of specific inhibitory control was exerted by the frequency of the tone, although the gradients were broad and shallow in slope.

A further experiment was conducted to see whether the modification of an excitatory gradient resulting from training to discriminate neighboring tones could arise from a simple interaction of inhibitory and excitatory gradients. The results indicated that it could not, since discrimination training produced a concentration of responding in the vicinity of the reinforced stimulus which cannot be derived from any plausible gradient of inhibition.

     

ERIC Counseling and Personnel Services Information Center

This article describes the development and planned use of the Counseling and Personnel Services Information Center, which is part of the Educational Research Information Center (ERIC).