Two masked prime arrows simultaneously affect a response to a target: Revealing of an additive unconscious priming effect.

Since there are many sources of unconscious information in our minds, there is a possibility that multiple channels of unconscious information can affect a response at the same time. However, this question has been largely ignored by researchers. In the present study, we presented two opposite pointing arrows as the masked primes followed by a target arrow. The results suggested that the two directions in which the two prime arrows are pointing influenced the response to the target simultaneously and additively, that is, the overall priming effect caused by the two opposite pointing prime arrows was equal to the net effect of the individual congruent effect elicited by the same pointing prime arrow and the individual incongruent priming effect induced by the prime arrow poitning in the opposite direction. In addition, in Experiment 1, a biased delayed response to the target was observed when the target arrow and the opposite pointing prime arrow were closely positioned in space due to Gestalt continuity and closure grouping. According to these results, the "independent unconscious influence" and "reverse unconscious selection" hypotheses are proposed.