We investigated contingent frequency effects in syntactic ambiguity resolution in three self-paced reading experiments. Experiment 1 demonstrated that the frequency with which that occurs as a determiner or a complementizer in different syntactic environments predicts readers initial parsing preferences. Experiments 2 and 3 demonstrated frequencyand regularity effects for reading the and that after different types of verbs that are similar to effects that have been well-documented in word recognition.

Linguistic devices that mark confidence (uncertainty) havebeen well documented (e.g., choice of modals, hedges, etc),yet there has been surprisingly little empirical work thatexplicitly measures how uncertainty is signaled andinterpreted. We present an initial report on a project designedto investigate how interlocutors communicate uncertainty anduse that information in acquiring new information andintegrating interlocutor based input with their prior beliefs.Experiment 1 establishes that speakers and listeners agree onthe relative degree of uncertainty for a set of phrases.Experiment 2 manipulated how likely it was that a participantwould recognize an object using images that varied inrecoverability, finding that recoverability mapped ontocertainty. Experiment 3 used a word-learning paradigm toestablish that learners take into account the certainty withwhich a speaker labels uses a novel word to label a novelshape.

An important aspect of language processing is the comprehender's ability to determine temporal relations between an event denoted by a verb and events already established in the discourse. This often requires the tense of a verb to be evaluated in relation to specific temporal discourse properties. W e investigate the time course of this process by examining how the temporal properties of a discourse influence the initial processing of temporarily ambiguous reduced relative clauses. M u c h of tfie empirical work on the reading of reduced relative clauses has revealed that readers experience a large mis-analysis effect (or *gardenpatfi') in reduced relatives like "The student spotted bv the proctor received a warning" because the reader has initially interpreted the verb "spotted" as a past tense verb in a main clause. Recent results from an eye movement study are provided which irnlicate that this mis-analysis of relative clauses can be eliminated when the temporal constraints of a discourse do not easily permit a main clause past tense interpretation. Such a flnding strongly suggests that readers process tense in relation to the temporal properties of the discourse, and that constraints from these properties can n^ndly influence processing at a stnKtural level.

Seidenberg and Tanenhaus (1979) demonstrated that orthographic information is obligatorily activated during auditory word recognition by showing that rhyme decisions to orthographically similar rhymes pie-tie were quicker than rhyme decisions to orthographically dissimilar rhymes ryetie. This effect could be due to the fact that orthographic and phonological codes axe closely inter-related in lexical memory and the two dimensions are highly correlated. However, it could also be a example of a more general similarity bias in making rhyme decisions, in which subjects cannot ignore irrelevant information from other dimensions. W e explored this later possibility by having subjects make rhyme decisions to words that vary in orthographic similarity and also to words that vary in semantic similarity {good-kind, cruel-kind). This possibility is ruled out in two experiments in which we fail to find an interference effect with semantically related trials, while replicating the basic orthographic interference and facilitation results.

Word frequency effects have long served as an empirical andtheoretical test bed for theories of language processing. Anumber of recent studies have suggested that Contextual Di-versity (CD) is a better metric of retrieval processes than wordfrequency. Motivated by these findings, we sketch an activeaccount of lexical access during sentence processing: lan-guage users store statistics about contextualized lexical rep-resentations and use lexical-contextual relations to both con-struct context and predict words given the context. In linewith our account, we provide evidence from a frequency judg-ment experiment suggesting that words are not stored indepen-dently of their contexts of use. To further examine CD effectsin reading, we analyzed reading times in self-paced readingand eye-tracking corpora. We demonstrate that as context isconstructed, the role of CD in lexical retrieval is attenuated,reflecting a trade-off between context construction and contex-tualized word prediction.

Children develop a sense of joint commitment and sharedintentionality during collaborative activities, which mayproduce prosocial effects in social coordinative activities.Past studies have found mixed results on the prosocial effectof shared intentionality. We hypothesized that it is the degreeof coordination and not simply shared intentionality thatfacilitates social bonding. In a block-assembly task with 4-year-old children, we manipulated degree of coordination.Children in the continuous high-level coordination conditionwere more generous in a Dictator Game and more willing tohelp their partner complete a task, compared with childrenwho engaged in a task with the same end-product thatrequired less coordination. Surprisingly, we also found thatboys shared more resources than girls, a result that weattributed to the emphasis on the importance of generosity formales in Chinese culture.

We investigated whether fine-grained coordination in a screen-based puzzle task with a (virtual) partner would influence on-line perspective-taking. Participants played a screen-basedpuzzle game with a computer player. In the high-coordinationcondition, the player presented participants with puzzle piecesthat could be placed near their partner’s last piece. In the low-coordination condition, pieces could only be placed furtheraway from their partner’s last piece. Participant’s eyemovements were then measured in a referential communicationtask, with the partner giving the instructions, and whetherpossible competitor referents were in shared or privilegedground. The results demonstrate clear effects of ground andcoordination. Participants in both coordination groups weresensitive to the perspective of the interlocutor. In addition,participants in the high-level coordination condition were moresensitive to statistical regularities in the input and theircomprehension was more time-locked to the utterance of thespeaker.