Abstract: Past research has found repetition priming effects in temporal order perception using binary temporal order judgments. However, according to a response bias explanation, such are caused by response biases derived from response options. In the present study, this hypothesis was tested in two experiments using ternary temporal order judgments.
Targets in each experiment were composed of pairs of figure stimuli: a square and a diamond. The two visual targets were presented either above or below the center of the screen at short temporal intervals or simultaneously. If primed, one of the targets was preceded by a repetition prime. In Experiment 1 20 participants were instructed to make ternary temporal order judgments including “a square appeared first”, “a diamond appeared first” and “a square and a diamond appeared simultaneously”. Experiment 2 explored the impact of restricting the use of “appearing simultaneously” judgments. In the condition with a restrictive instruction, 14 participants were asked to use “appearing simultaneously” judgments only if they had undoubtedly perceived simultaneous presentations. In the unrestricted condition they could indicate perceived simultaneity as well as uncertainty with “appearing simultaneously” judgments.
The research results in two important findings: First, there were significant repetition priming effects on temporal order perception with ternary temporal order judgments in both experiments. Furthermore, the influence of repetition priming was involved in the perception of both simultaneity in Experiments 1 and 2.
Based on these findings, it can be concluded that the repetition priming effect on temporal order perception was not the false effect caused by response option bias, and that temporal order perception of both simultaneity and order had repetition priming effects.

Key words: repetition priming, temporal order, perception, response option