Contrasting intrusion profiles for agreement and anaphora: Experimental and modeling evidence

We investigated the relationship between linguistic representation and memory access by comparing the processing of two linguistic dependencies that require comprehenders to check that the subject of the current clause has the correct morphological features: subject-verb agreement and reflexive anaphors in English. In two eye-tracking experiments we examined the impact of structurally illicit noun phrases on the computation of reflexive and subject-verb agreement. Experiment 1 directly compared the two dependencies within participants. Results show a clear difference in the intrusion profile associated with each dependency: agreement resolution displays clear intrusion effects in comprehension (as found by Pearlmutter, Garnsey, & Bock, 1999; Wagers, Lau, & Phillips, 2009), but reflexives show no such intrusion effect from illicit antecedents (Sturt, 2003; Xiang, Dillon, & Phillips, 2009). Experiment 2 replicated the lack of intrusion for reflexives, confirming the reliability of the pattern and examining a wider range of feature combinations. In addition, we present modeling evidence that suggests that the reflexive results are best captured by a memory retrieval mechanism that uses primarily syntactic information to guide retrievals for the anaphor's antecedent, in contrast to the mixed morphological and syntactic cues used resolve subject-verb agreement dependencies. Despite the fact that agreement and reflexive dependencies are subject to a similar morphological agreement constraint, in online processing comprehenders appear to implement this constraint in distinct ways for the two dependencies.