On the nature of neutral primes in a lexical decision task

Summary Research concerned with semantic priming has used a neutral prime as a benchmark for measuring the amount of facilitation for related targets and the amount of inhibition for unrelated targets. Recently, de Groot, Thomassen, and Hudson (1982) have reported that lexical decisions to targets are faster when preceded by the neutral prime BLANK as compared to a neutral prime consisting of a string of X's. Additionally, Antos (1979) has reported that an X neutral prime induces an inhibitory effect when the stimulus-onset-asynchrony (SOA) is short. The present experiment manipulated class of neutral prime, SOA, and practice. The results failed to support the observation by Antos. However, the results did support the finding by de Groot et al. at shorter SOA's (200 and 550 ms). At a longer (1000 ms) SOA the effect of the two neutral primes as well as the effect of the unrelated primes were equivalent. Practice had no differential effect on either of the neutral primes as compared to the unrelated priming conditions. These results were interpreted to mean that the difference between the two neutral primes at a brief SOA were perceptual in origin and that an unrelated word prime is neutral with respect to the target in the absence of strategic priming effects.