Perceptual defence: Attempted replication using the dark adaptation paradigm.

Abstract

Worthington reported an experiment in which a perceptual defence effect on the course of dark adaptation was found. Two experiments are described which sought to repicate Worthington''s findings. Their failure to show a perceptual defence effect is considered to throw doubt on the replicability of the original study. Both experiments 1 and 2 were carefully based on Worthington''s. The evidence is discussed in terms of experimenter effects and bias. A possible critism of the present research is that negative E bias may have been exerted on the conduct on the experiment. Both cue-specific and diffuse negative experimenter bias are rebutted as explanations of the failure to replicate.