The first glimpse determines the perception of an ambiguous figure

The ambiguous rat-man figure was tachistoscopically presented to 36 subjects in successive segments to test the hypothesis that the starting segment would determine the perception of the figure. Starting segments were selected which were expected to produce the perception of a rat, a man, or either a rat or man. The remaining segments came from figures evaluated in a preliminary study. The selected figures differed in drawn bias and tended to be seen as a rat, a man, or either a rat or a man. The three starting segments were combined factorially with the three levels of drawn bias of the remaining segments. The effect of the starting segment was significant; the effect of drawn bias was not. A further experiment showed that presentation of the rat vs. man starting segments by themselves did not produce a reliable difference. The results support a constructive model of form perception in which the stimulus material first presented establishes a hypothesis which is used to interpret the remaining material.