“Reactive Inhibition” in the Sowbug

Abstract

Four groups of twenty isopods (Porcellio scaber L.) were given 40 right turns and four groups were given 20 right turns in square mazes 1, 1.5, 2.5, and 4 cm. on a side. Another four groups were run equivalent distances without turns, and one group was given no treatment at all. Ss from all groups then received one trial in a T-maze. Left turns in the T-maze increased as a function of number of prior turns and decreased with distance (time) between turns. These results were obtained in a situation where “centrifugal swing” and “forward-going tendency” hypotheses provide no useful predictions. In comparing these results and procedures with those of other investigations, it is apparent that I_R is typically a weak determiner of choice-point behavior in isopods, but under special circumstances can be the principal source of variance.