How perceptual processes help to generate new meaning: an EEG study of chunk decomposition in Chinese characters.

Chunk decomposition has been regarded as an important process in problem solving that helps problem solvers to generate new solution paths through changing inappropriate problem representations. We studied the neural bases of chunk decomposition in Chinese characters using the electroencephalogram (EEG). Participants decomposed Chinese characters either at the level of radicals or at the level of strokes to generate new target characters with a different meaning. We hypothesized that decomposition at the stroke level would require a more fundamental change in the problem representation that should involve differences in basic visual processing. To test this hypothesis, we compared the alpha rhythm (8-13 Hz) over parietal-occipital regions between the two different conditions. The regrouping of tight chunks (stroke level) exhibited a stronger alpha activation than the regrouping of loose chunks approximately 500 ms prior to response. Thus visual areas were less active during the decomposition of tight chunks. Together with a previous fMRI study the results provide convincing evidence that attenuation of early visual information is required to generate new meaning.