Functional cerebral lateralisation; dichotomy or plurality?

Cartoon faces were presented tachistoscopically in the right and left visual fields, and required to be matched to a previously memorised target face. The three different stimuli differed from the target either on only one, or on all three features (eyes, nose, mouth). Reaction times varied considerably across the individual different responses in both conditions. In the first condition field differences consistently favoured the right field; in the second, two favoured the left and the third the right. In both conditions same responses were faster than at least one different response class. Several interpretations in terms of the distinction between "analytic" and "holistic" processes were entertained. Such processes themselves remain somewhat obscure, but there is nothing in the data to suggest that the two cerebral hemispheres might not be essentially ambivalent in their predilections for the two kinds of processing. In which case future research might profitably focus on the emerging plurality of experimental factors governing this cognitive ambivalence, rather than on the simple physical dichotomy.