Abstractionist versus exemplar-based theories of visual word priming: a subsystems resolution.

Three experiments addressed abstractionist versus exemplar-based theories of the visual representations underlying word priming. Participants first read centrally presented whole words (each displayed in all lowercase or in all uppercase letters), and then they completed laterally presented word stems (each displayed in all lowercase or in all uppercase letters). Word stem completion priming was letter-case specific (greater for same-case primed items than for different-case primed items) when stems were presented directly to the right cerebral hemisphere but not when stems were presented directly to the left cerebral hemisphere. This interaction was not influenced by the typicality of the test stems, but it was observed only for stems composed of letters with visually dissimilar lowercase and uppercase structures (e.g., bea/BEA) and not for stems composed of letters with visually similar lowercase and uppercase structures (e.g., sco/SCO). In contrast, cued recall was letter-case specific when similar-case or dissimilar-case stems were presented directly to the right hemisphere. Results do not support strongly abstractionist or exemplar-based theories. Instead, they suggest a resolution to these differing perspectives: Relatively independent neural subsystems operate in parallel to underlie abstract-category and specific-exemplar priming of word forms.