Response to stimulus complexity in the Rat

Abstract

An experiment is reported that is relevant to the Dember-Earl (1957) theory of stimulus complexity. Two mazes were constructed. One had four compartments in which the patterns painted on the walls were varied in complexity, and in the other, the number of baffles was varied as a three-dimensional manipulation of stimulus complexity. Thirty-two naive, male, hooded rats were divided into two equal groups, one group for each maze. Animals were placed individually in one of the mazes for 30 min. per day for 5 days. Higher complexity interaction index scores were achieved in the baffle pattern maze than in the wall pattern maze. There was some increase in the complexity of the preferred compartment over days. The results raise questions concerning the theoretical and experimental treatment of the stimulus complexity variable. The behavior of the animals appears to require a two-process explanation including an initial ‘information gaining’ exploratory phase. There appears to be need for a more general theory in addition to that proposed by Dember and Earl.