| |
Abstract:
Semantic network models propose that automatic (e.g.
spreading activation) and controlled processes are involved in
semantic priming. Behavioral studies propose that the influence of
each of these processes depends on the stimulus onset asynchrony
(SOA). To investigate this hypothesis with a more sensitive method
we applied high resolution event related potential (ERP) measures
to a word-pseudoword lexical decision task which contained direct,
indirect, and nonrelated prime-target pairs. SOAs consisted of 150
or 700 ms. The results showed that independently of SOA increasing
semantic distance prolonged reaction times and enlarged N400
amplitudes. Furthermore, the word-pseudoword decision evoked a
parieto-central late positive complex (LPC respectively delayed
P300) which was sensitive for semantic relatedness in the short SOA
only. Additionally, we found two early frontal components: A P250
in the short SOA only and a N310 sensitive to semantic relatedness
more prominent in the short SOA. We conclude that ERP-differences
between both SOAs indicate two separate processes: (1) An access to
semantic memory which is facilitated by spreading activation in the
short SOA only, and (2), SOA-independent, a controlled process
which integrates prime and target word into a semantic
context.
|
