Biasing Effects in Ambiguous Figures: Removal or Fixation of Critical Features Can Affect Perception

The role of so-called critical features in the perception of ambiguous figures was examined in two experiments. In the first, selective removal of certain features was found to bias the initial perception of the wife mother-in-law figure. In the second, the position of the fixation point was found to influence the dominance of aspect of the wife mother-in- law figure. During an extended viewing period, when the fixation point was close to a critical feature (as defined in the first experiment), the tendency was for the figure to be less ambiguous, and for large figures to be less ambiguous than small. The effects are discussed with reference to the hypothesis that changes of visual attention between different features underlie the perceptual alternations of the figure.