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Abstract:
Although numerous studies depict a strict dichotomy between
serial and parallel processing, some researchers have eluded that a
processing continuum may be more correct (e.g. Duncan &
Humphreys, 1989; Saarinen, 1996; Theeuwes, 1994). Using a popout
paradigm with three target stimuli, our lab previously established
that a continuum of processing (from serial to parallel) exists
based on reaction times (RTs) and the amplitude of the P300
component of the visual evoked potential (VEP). To further examine
this processing continuum the current study evaluated the RTs and
VEPs with three new target stimuli to determine their location
along the processing continuum. To develop appropriate target
stimuli, eight figures whose features were altered from our
original experiment, were ranked along a continuum from serial to
parallel by 40 undergraduate students. Stimuli were selected
according to those that fell between the original target stimuli.
RTs established that the stimuli chosen were processed along the
serial to parallel continuum and correlated well with the previous
ranking. RTs showed that stimuli which required more visual search
were processed more serially and those that had greater popout
value at a more parallel level. The VEPs supported the processing
continuum with the parallel processed stimuli eliciting greater
P300 amplitude. These results strengthen the theory of a serial to
parallel processing continuum.
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