Unconscious congruency priming from unpracticed words is modulated by prime-target semantic relatedness.

Participants performed a 2-choice categorization task on visible word targets that were preceded by novel (unpracticed) prime words. The prime words were presented for 33 ms and followed either immediately (Experiments 1-3) or after a variable delay (Experiments 1 and 4) by a pattern mask. Both subjective and objective measures of prime visibility were used in all experiments. On 80% of the trials the primes and targets belonged to different categories (incongruent trials), whereas in the remaining 20% (congruent trials) they could be either strong or weak semantically related category members. Positive congruency effects (reaction times faster on congruent than on incongruent trials) were consistently found, but only when the mask immediately followed the primes, and participants reported being unaware of the identity of the primes. Primes followed by a delayed mask (such that participants reported being aware of their identity) produced either nonreliable facilitation or reliable reversed priming (strategic), depending on whether the prime-target stimulus onset asynchrony was either short (200 ms; Experiments 1 and 4) or long (1,000 ms; Experiment 4). Facilitatory priming with immediate mask was found strong (a) even for participants who performed at chance in prime visibility tests; and (b) for high but not for weakly semantically related category coordinates, irrespective of category size (animals, body parts). These findings provide evidence that unconscious congruency priming by unpracticed words from large stimulus sets critically depends on associative strength and/or semantic similarity between category coexemplars.

Influence of spatial attention on conscious and unconscious word priming.

We used a qualitative dissociation procedure to assess semantic priming from spatially attended and unattended masked words. Participants categorized target words that were preceded by parafoveal prime words belonging to either the same (20%) or the opposite (80%) category as the target. Using this paradigm, only non-strategic use of the prime would result in facilitation of the target responses in related trials. Primes were immediately masked or masked with a delay, while spatial attention was allocated to the primes' location or away from the primes' location. Immediate masked, strongly related primes facilitated target responses irrespective of the spatial attention. Delayed masked, related primes led to reversed (strategic) or facilitatory priming depending on whether they were cued or uncued. These findings demonstrate that perceiving a stimulus with or without awareness depends on both stimulus quality and attention orienting and that non-strategic priming can be observed from clear visible but spatially unattended words.