Neighborhood Size and Neighborhood Frequency Effects in Word Recognition

What are the effects of a word's orthographic neighborhood on the word recognition process? Andrews (1989) reported that large neighborhoods facilitate lexical access (the neighborhood size effect). Grainger, O'Regan, Jacobs, & Segui (1989) reported that higher frequency neighbors inhibit lexical access (the "neighborhood frequency effect"). Because neighborhood size and neighborhood frequency typically covary (words with large neighborhoods will usually possess higher frequency neighbors), these findings would seem to contradict one another. In the present study, 6 experiments on the effects of neighborhood size and neighborhood frequency indicated that, at least for low-frequency words, large neighborhoods do facilitate processing. However, the existence of higher frequency neighbors seems to facilitate rather than inhibit processing. The implications of these findings for serial and parallel models of lexical access are discussed.