Behavioral and neural correlates of deep and surface anaphora

Abstract

Anaphora in language is defined as an expression that refers to another expression. Hankamer & Sag 1976 and Sag & Hankamer 1984 proposed that anaphors can be divided into deep anaphors, which are resolved using a non-linguistic discourse-level interpretation of the antecedent, and surface anaphors, which are resolved by accessing their antecedents at a linguistic level which is highly determined by surface syntactic structure. Previous behavioral studies of the differences between deep and surface anaphors have conflicting and inconsistent results. Additionally, no neuroimaging studies have previously been conducted on deep and surface anaphors or on verb-phrase anaphora in general. Using two sets of materials which differed in whether they used a surface or a deep anaphor, the behavioral and neural responses as a function of anaphor type were determined. One set of materials was used to examine the effect of placing an intervening sentence between the antecedent and anaphor (distance materials), and one set was used to examine the effect of shifted word order (particle shift materials), both of which were expected to affect surface anaphors more than deep anaphors. Behavioral responses were measured using naturalness ratings and self-paced reading times, and neural responses were measured using blood-oxygenlevel dependent (BOLD) signal differences obtained with functional magnetic resonance imaging (fMRI). Increasing the distance between the antecedent and anaphor affected surface anaphors more than deep anaphors in naturalness ratings, question response times, and BOLD signal, while altering word order had similar or insignificant effects on surface and deep anaphors. These results are consistent with Sag and Hankamer's idea that surface and deep anaphora are distinct categories that are processed differently, but are not consistent with the exact level of access of surface anaphora proposed by Sag and Hankamer. Instead, the results suggest that surface anaphors are more dependent on syntactic information that decays over distance than deep anaphors, but do not differ from deep anaphors in terms of accessing exact surface word order information.