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Abstract:
Abstract: We examined differences in brain activation between
expert and novice concept learning by comparing a well-learned and
a novel classification task within-subjects. The stimuli used in
each task were defined according to Ashby & Maddox (1993), and
were simple visual figures (rectangles; intersecting lines) that
could vary along two dimensions (height and width; line length and
angle between lines). For each task, prototypes were formed for
categories A and B. Exemplars were formed by varying the dimensions
according to a normal distribution with a fixed standard deviation.
Prototype mean feature values and standard deviations were chosen
so that participants learning an ideal decision bound between
categories would be able to correctly classify stimuli with an
accuracy of 80%. For the Well-learned concept, participants were
trained to criterion (2 consecutive blocks of >75% accuracy)
prior to scanning. During scanning, participants classified
exemplars from the Well-learned and Novel tasks in separate blocks
alternating with a simple baseline task. With respect to baseline,
both Well-learned and Novel classifications activated bilateral
inferior parietal lobes and bilateral fusiform gyri. The
Well-learned classification activated left prefrontal areas,
whereas Novel classification activated bilateral prefrontal areas.
These results are consistent with those of Seger et al. (in press),
who associated right frontal activation with processing of novel
exemplars early in classification training, and associated left
frontal activation with successful learning.
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