Abstract: Line-drawn figures were used as stimuli in this experiment, figure A in-dicated a rat, figure B was an ambiguous figure and figure C indicated anold man. According to two orders of presentation (A→B→C and C→B→A),these pictures were presented to the subjects. 40 subjects were divided into twoequal groups. ERPs were recorded while the subjects recepted the visual stimu-li. After the presentation of figure B, the subjects were asked to report thecontent of the picture. Analyzing the reports, it was found that the ambigu-ous figure was recognized as a rat in the first order of presentation whileit was recognized as an old man in the second order. The latencies of P2evoked by the ambiguous figure as face stimulus at T3 and Pz were longerthan those by the figure as non-face stimulus, and the latencies of P3 evokedby the ambiguous figure as face stimulus at T3、T4、Pz and Oz were longerthan those by the figure as non-face stimulus; there was no change in theamplitudes of P2 and P3.

Key words: ambiguous figure, face stimulus, non-face stimulus, ERPs