Abstract: In our previous study it was found that there was a reversal of the repetition priming effect when the primed stimulus appeared first in judging the temporal order of a primed and an unprimed stimulus —an effect that has not been observed in other studies. Because the models proposed previously were not adequate in explaining such reversal, it is hypothesized that dual process and representation matching modulating can explain the results. Two experiments were conducted in the present study to test this hypothesis.
Targets in the experiments were composed of a pair of figure stimuli: a square and a diamond. The target pair was presented either above or below the center of the screen. If primed, one of the targets was preceded by a repetition prime. The temporal intervals between the two targets were -112 to +112 ms in steps of 28 ms (Positive numbers indicated that the primed figure preceded the unprimed figure, whereas negative numbers indicated that the unprimed figure appeared first and 0 ms meant the primed figure and unprimed figure appeared simultaneously) and participants were instructed to make temporal order judgments by responding which of two targets appeared first in Experiments 1 and 2. The prime appeared either in the center of the screen or in the same position as the primed target in Experiment 1, and the prime appearing in the center of the screen was either masked by a circle including 16 diametral line segments or not masked in Experiment 2.
The results were as follows: (1) the reversal of the repetition priming effect disappeared when the prime was presented in the same position as the primed target in Experiment 1; (2) the reversal of the repetition priming effect almost disappeared when the prime was presented in the center of the screen and was then masked in Experiment 2.
It can be concluded that the present study provides evidence in support of the hypothesis about dual processes and representation matching modulation that can better explain the mechanism of the repetition priming effect on temporal order perception.

Key words: repetition priming, temporal order perception, hypothesis about dual processes and representation matching modulation