Evidence for the automatic processing of prelexical codes in an orthographic but not a phonological task.

The automatic activation of phonological and orthographic information in auditory and visual word processing was examined using a task-set procedure. Participants engaged in a phonological task (i.e., determining whether the letter "a" in a word sounded like /e/ or /æ/) or an orthographic task (i.e., determining whether the sound /s/ in a word was spelled with an "s" or a "c"). Participants were cued regarding which task to perform simultaneously with, or 750 ms before, a clear or degraded target. The stimulus clarity effect (i.e., clear words responded to faster than degraded words) was absorbed into the time that it took participants to identify the task on the basis of the cue in a simultaneous cue-target as compared to a delayed cue-target condition, but only for the orthographic task. These data are consistent with the claim that prelexical processing occurs in a capacity-free manner upon stimulus presentation when participants are trying to extract orthographic codes from words presented in the visual and auditory modalities. Such affirmative data were not obtained when participants attempted to extract phonological codes from words, since here the effects of stimulus clarity and cue delay were additive.