Differences in top-down influences on the reversal rate of different categories of reversible figures.

Understanding the mechanisms underlying the multistability of reversible figures may provide valuable insights into the normal functioning of our visual system. The proposed factors that control the perceptual alternations of reversible figures can be classified into bottom-up and top-down processes. In the present study, we report differences in top-down effects on the reversal rate depending on whether a structural perspective (Necker cube, Schröder staircase) or a meaningful content (duck/rabbit figure, chef/dog figure) is subject to the reversal phenomenon. In order to activate top-down mechanisms explicitly the subjects had the instruction to bring the reversal rate under voluntary control. The results indicated that both slowing down and speeding up the rate of alternations was more effective for the content-reversal figures (duck/rabbit, chef/dog) than for the rather abstract perspective-reversal figures (Necker cube, Schröder staircase). In order to investigate the effect of meaningfulness in figure/ground reversals, the effect of the same instructional variable was also determined for Rubin's vase/faces and the Maltese cross. The results showed a similar tendency as in the case of the comparison between perspective reversals and content reversals. Possible cognitive processes that may play a role in top-down influences on figure reversal and theoretical implications of these findings for the interaction of bottom-up and top-down processes are discussed.