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Abstract:
Semantic priming, the increased activation of one word by the
presentation of another word, is generally described as a process
of spreading activation through the network of semantic
associations (Collins & Loftus, 1975). Like many other
processes, priming can be carried out in either an automatic or
conscious fashion (Posner & Snyder, 1975). In a classic study
(Neely, 1977), it was shown that automatic priming takes place
before 250 msec. whereas at least 400 msec. is necessary for
conscious expectations to produce semantic priming. From a
cognitive neuroscience perspective, a question that remains is
whether different neural systems are involved in automatic and
controlled priming. An ERP replication of the Neely (1977) study
was carried out with 128 channels. Automatic priming was produced
when a prime like "bird" was followed by a related word like
"robin." Controlled priming was produced when the subject was
instructed to expect a word class (like birds) to follow an
unrelated prime like "building". Consistent with a previous study
(Dien, Frishkoff, Cerbone, & Tucker, submitted), targets
preceded by related primes produced a larger N2 whereas targets
that violated conscious expectations produced by an unrelated prime
produced a larger N400. These results suggest that automatic and
conscious priming are mediated by different neural systems.
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