Neural correlates of the orthographic neighborhood size effect in Chinese

Word recognition research with alphabetical scripts has revealed a facilitatory neighborhood size effect, whereby naming of words with more orthographic neighbors is faster than that of words with fewer neighbors. Preliminary behavioral evidence in Chinese revealed both facilitatory and inhibitory neighborhood size effects, depending on whether there are higher-frequency neighbors (HFNs) than the target. This functional magnetic resonance imaging study examined the neural substrates of the neighborhood size effect with silent naming. Neighborhood size and the HFN factor were factorially manipulated. Behavioral results replicated previous findings showing that larger neighborhood size facilitated naming in the absence of HFNs, but inhibited naming in their presence. Imaging results identified greater activation in the left middle frontal gyrus for small than larger neighborhood size, and bilateral inferior frontal activations for the with-HFN condition as compared with the without-HFN condition. Critically, there was an interaction in the right middle occipital gyrus showing greater activation for large than for small neighborhood size in the absence of HFNs but no neighborhood size effect in their presence. The results support a proposal that, in addition to a facilitatory contribution from orthographic activation of neighborhoods, naming is also affected by whether there are higher-frequency neighbors, particularly in scripts with deep orthography, where orthographically similar words can be pronounced very differently.