This study aimed to identify different processes in working
memory, using event-related potentials (ERPs) and response
times. Abstract polygons were presented for memorization
and subsequent recall in a delayed matching-to-sample paradigm.
Two polygons were presented bilaterally for memorization
and a cue indicated whether one (and if so, which one of
the two) or both polygons had to be memorized. A subsequent
test figure was presented unilaterally to the left or right
visual field and had to be compared with the memorized
figure(s). ERP results suggested that memorization takes
place in a visual buffer in contralateral posterior brain
areas, whereas identification of the test stimulus as a
target appears to be mainly a left hemispheric process.
Increased response times were found for nontarget test
stimuli as compared to targets, and for target test stimuli
that were presented contralaterally with respect to the
location of the memorized stimulus. In addition, response
times were slower when two figures were memorized than
when only one was memorized.