Adaptation effects and reversible figures: A comment on Horlitz and O’Leary

In a recent article, Horlitz and O’Leary (1993) offer a reinterpretation of the results of several studies over the past 40 years that have employed the prolonged-inspection technique in the investigation of reversible figures. Specifically, they contend that, contrary to the favored interpretation of neural adaptation effects, the results of these studies reveal the combined influence of such topdown processes as attention and perceptual learning as well as such methodological difficulties as unwanted demand characteristics. In this note, we examine their analysis of the literature, their alternative theoretical model, and the supporting conclusions they draw from their two experiments. We argue that there is considerable evidence from a variety of studies for the joint role of bottom-up and top-down processes in reversible figures. Moreover, we propose that Horlitz and O’Leary’s own research, rather than eliminating the possibility of neural-adaptation effects, is best conceptualized as providing additional evidence for the role of higher-order processes in these phenomena.