A speaker's manner of delivery of an utterance can affect a listener's pragmatic interpretation of the message. Disfluencies (such as filled pauses) influence a listener's off-line assessment of whether the speaker is truthful or deceptive. Do listeners also form this assessment during the moment-by-moment processing of the linguistic message? Here we present two experiments that examined listeners' judgments of whether a speaker was indicating the true location of the prize in a game during fluent and disfluent utterances. Participants' eye and mouse movements were biased toward the location named by the speaker during fluent utterances, whereas the opposite bias was observed during disfluent utterances. This difference emerged rapidly after the onset of the critical noun. Participants were similarly sensitive to disfluencies at the start of the utterance (Experiment 1) and in the middle (Experiment 2). Our findings support recent research showing that listeners integrate pragmatic information alongside semantic content during the earliest moments of language processing. Unlike prior work which has focused on pragmatic effects in the interpretation of the literal message, here we highlight disfluency's role in guiding a listener to an alternative non-literal message.

Replication studies in psychological science sometimes fail to reproduce prior findings. If these studies use methods that are unfaithful to the original study or ineffective in eliciting the phenomenon of interest, then a failure to replicate may be a failure of the protocol rather than a challenge to the original finding. Formal pre-data-collection peer review by experts may address shortcomings and increase replicability rates. We selected 10 replication studies from the Reproducibility Project: Psychology (RP:P; Open Science Collaboration, 2015) for which the original authors had expressed concerns about the replication designs before data collection; only one of these studies had yielded a statistically significant effect ( p < .05). Commenters suggested that lack of adherence to expert review and low-powered tests were the reasons that most of these RP:P studies failed to replicate the original effects. We revised the replication protocols and received formal peer review prior to conducting new replication studies. We administered the RP:P and revised protocols in multiple laboratories (median number of laboratories per original study = 6.5, range = 3–9; median total sample = 1,279.5, range = 276–3,512) for high-powered tests of each original finding with both protocols. Overall, following the preregistered analysis plan, we found that the revised protocols produced effect sizes similar to those of the RP:P protocols (Δ r = .002 or .014, depending on analytic approach). The median effect size for the revised protocols ( r = .05) was similar to that of the RP:P protocols ( r = .04) and the original RP:P replications ( r = .11), and smaller than that of the original studies ( r = .37). Analysis of the cumulative evidence across the original studies and the corresponding three replication attempts provided very precise estimates of the 10 tested effects and indicated that their effect sizes (median r = .07, range = .00–.15) were 78% smaller, on average, than the original effect sizes (median r = .37, range = .19–.50).

Are the cues that speakers produce when lying the same cues that listeners attend to when attempting to detect deceit? We used a two-person interactive game to explore the production and perception of speech and nonverbal cues to lying. In each game turn, participants viewed pairs of images, with the location of some treasure indicated to the speaker but not to the listener. The speaker described the location of the treasure, with the objective of misleading the listener about its true location; the listener attempted to locate the treasure, based on their judgement of the speaker’s veracity. In line with previous comprehension research, listeners’ responses suggest that they attend primarily to behaviours associated with increased mental difficulty, perhaps because lying, under a cognitive hypothesis, is thought to cause an increased cognitive load. Moreover, a mouse-tracking analysis suggests that these judgements are made quickly, while the speakers’ utterances are still unfolding. However, there is a surprising mismatch between listeners and speakers: When producing false statements, speakers are less likely to produce the cues that listeners associate with lying. This production pattern is in keeping with an attempted control hypothesis, whereby liars may take into account listeners’ expectations and correspondingly manipulate their behaviour to avoid detection.

for their encouragment, supervision and feedback throughout. I am very grateful to Jia Loy for providing the basis on which many of the experiments in the second half of this thesis are built (and for all the discussions, feedback, and everything else she's helped with); to Caroline McHutchison for all round general support and agreeing to sit in front of a camera and produce so many awkward gestures; and to Sacha the cat for consistently waking me up so early. I would also like to acknowledge the