The Trajectory of Truth: A Longitudinal Study of the Illusory Truth Effect.

Repeated statements are rated as subjectively truer than comparable new statements, even though repetition alone provides no new, probative information (the illusory truth effect). Contrary to some theoretical predictions, the illusory truth effect seems to be similar in magnitude for repetitions occurring after minutes or weeks. This Registered Report describes a longitudinal investigation of the illusory truth effect (n = 608, n = 567 analysed) in which we systematically manipulated intersession interval (immediately, one day, one week, and one month) in order to test whether the illusory truth effect is immune to time. Both our hypotheses were supported: We observed an illusory truth effect at all four intervals (overall effect: χ 2(1) = 169.91; M repeated = 4.52, M new = 4.14; H1), with the effect diminishing as delay increased (H2). False information repeated over short timescales might have a greater effect on truth judgements than repetitions over longer timescales. Researchers should consider the implications of the choice of intersession interval when designing future illusory truth effect research.

Dissociable effects of prediction and integration during language comprehension: evidence from a large-scale study using brain potentials.

Composing sentence meaning is easier for predictable words than for unpredictable words. Are predictable words genuinely predicted, or simply more plausible and therefore easier to integrate with sentence context? We addressed this persistent and fundamental question using data from a recent, large-scale (n = 334) replication study, by investigating the effects of word predictability and sentence plausibility on the N400, the brain's electrophysiological index of semantic processing. A spatio-temporally fine-grained mixed-effect multiple regression analysis revealed overlapping effects of predictability and plausibility on the N400, albeit with distinct spatio-temporal profiles. Our results challenge the view that the predictability-dependent N400 reflects the effects of either prediction or integration, and suggest that semantic facilitation of predictable words arises from a cascade of processes that activate and integrate word meaning with context into a sentence-level meaning. This article is part of the theme issue 'Towards mechanistic models of meaning composition'.

Large-scale replication study reveals a limit on probabilistic prediction in language comprehension.

Do people routinely pre-activate the meaning and even the phonological form of upcoming words? The most acclaimed evidence for phonological prediction comes from a 2005 Nature Neuroscience publication by DeLong, Urbach and Kutas, who observed a graded modulation of electrical brain potentials (N400) to nouns and preceding articles by the probability that people use a word to continue the sentence fragment ('cloze'). In our direct replication study spanning 9 laboratories (N=334), pre-registered replication-analyses and exploratory Bayes factor analyses successfully replicated the noun-results but, crucially, not the article-results. Pre-registered single-trial analyses also yielded a statistically significant effect for the nouns but not the articles. Exploratory Bayesian single-trial analyses showed that the article-effect may be non-zero but is likely far smaller than originally reported and too small to observe without very large sample sizes. Our results do not support the view that readers routinely pre-activate the phonological form of predictable words.

Conversational Interaction in the Scanner: Mentalizing during Language Processing as Revealed by MEG.

Humans are especially good at taking another's perspective-representing what others might be thinking or experiencing. This "mentalizing" capacity is apparent in everyday human interactions and conversations. We investigated its neural basis using magnetoencephalography. We focused on whether mentalizing was engaged spontaneously and routinely to understand an utterance's meaning or largely on-demand, to restore "common ground" when expectations were violated. Participants conversed with 1 of 2 confederate speakers and established tacit agreements about objects' names. In a subsequent "test" phase, some of these agreements were violated by either the same or a different speaker. Our analysis of the neural processing of test phase utterances revealed recruitment of neural circuits associated with language (temporal cortex), episodic memory (e.g., medial temporal lobe), and mentalizing (temporo-parietal junction and ventromedial prefrontal cortex). Theta oscillations (3-7 Hz) were modulated most prominently, and we observed phase coupling between functionally distinct neural circuits. The episodic memory and language circuits were recruited in anticipation of upcoming referring expressions, suggesting that context-sensitive predictions were spontaneously generated. In contrast, the mentalizing areas were recruited on-demand, as a means for detecting and resolving perceived pragmatic anomalies, with little evidence they were activated to make partner-specific predictions about upcoming linguistic utterances.

Cultural selection drives the evolution of human communication systems.

Human communication systems evolve culturally, but the evolutionary mechanisms that drive this evolution are not well understood. Against a baseline that communication variants spread in a population following neutral evolutionary dynamics (also known as drift models), we tested the role of two cultural selection models: coordination- and content-biased. We constructed a parametrized mixed probabilistic model of the spread of communicative variants in four 8-person laboratory micro-societies engaged in a simple communication game. We found that selectionist models, working in combination, explain the majority of the empirical data. The best-fitting parameter setting includes an egocentric bias and a content bias, suggesting that participants retained their own previously used communicative variants unless they encountered a superior (content-biased) variant, in which case it was adopted. This novel pattern of results suggests that (i) a theory of the cultural evolution of human communication systems must integrate selectionist models and (ii) human communication systems are functionally adaptive complex systems.

Using a voice to put a name to a face: the psycholinguistics of proper name comprehension.

We propose that hearing a proper name (e.g., Kevin) in a particular voice serves as a compound memory cue that directly activates representations of a mutually known target person, often permitting reference resolution without any complex computation of shared knowledge. In a referential communication study, pairs of friends played a communication game, in which we monitored the eyes of one friend (the addressee) while he or she sought to identify the target person, in a set of four photos, on the basis of a name spoken aloud. When the name was spoken by a friend, addressees rapidly identified the target person, and this facilitation was independent of whether the friend was articulating a message he or she had designed versus one from a third party with whom the target person was not shared. Our findings suggest that the comprehension system takes advantage of regularities in the environment to minimize effortful computation about who knows what.

How culture influences perspective taking: differences in correction, not integration.

Individuals from East Asian (Chinese) backgrounds have been shown to exhibit greater sensitivity to a speaker's perspective than Western (U.S.) participants when resolving referentially ambiguous expressions. We show that this cultural difference does not reflect better integration of social information during language processing, but rather is the result of differential correction: in the earliest moments of referential processing, Chinese participants showed equivalent egocentric interference to Westerners, but managed to suppress the interference earlier and more effectively. A time-series analysis of visual-world eye-tracking data found that the two cultural groups diverged extremely late in processing, between 600 and 1400 ms after the onset of egocentric interference. We suggest that the early moments of referential processing reflect the operation of a universal stratum of processing that provides rapid ambiguity resolution at the cost of accuracy and flexibility. Late components, in contrast, reflect the mapping of outputs from referential processes to decision-making and action planning systems, allowing for a flexibility in responding that is molded by culturally specific demands.

Random effects structure for confirmatory hypothesis testing: Keep it maximal.

Linear mixed-effects models (LMEMs) have become increasingly prominent in psycholinguistics and related areas. However, many researchers do not seem to appreciate how random effects structures affect the generalizability of an analysis. Here, we argue that researchers using LMEMs for confirmatory hypothesis testing should minimally adhere to the standards that have been in place for many decades. Through theoretical arguments and Monte Carlo simulation, we show that LMEMs generalize best when they include the maximal random effects structure justified by the design. The generalization performance of LMEMs including data-driven random effects structures strongly depends upon modeling criteria and sample size, yielding reasonable results on moderately-sized samples when conservative criteria are used, but with little or no power advantage over maximal models. Finally, random-intercepts-only LMEMs used on within-subjects and/or within-items data from populations where subjects and/or items vary in their sensitivity to experimental manipulations always generalize worse than separate F1 and F2 tests, and in many cases, even worse than F1 alone. Maximal LMEMs should be the 'gold standard' for confirmatory hypothesis testing in psycholinguistics and beyond.

Anticipatory baseline effects and information integration in visual world studies.

Researchers often conduct visual world studies to investigate how listeners integrate linguistic information with prior context. Such studies are likely to generate anticipatory baseline effects (ABEs), differences in listeners' expectations about what a speaker might mention that exist before a critical speech stimulus is presented. ABEs show that listeners have attended to and accessed prior contextual information in time to influence the processing of the critical speech stimulus. However, further evidence is required to show that the information actually did influence subsequent processing. ABEs can compromise the validity of inferences about information integration if they are not appropriately controlled. We discuss four solutions: statistical estimation, experimental control, elimination of "on-target" trials, and neutral gaze. An experiment compares the performance of these solutions, and suggests that the elimination of on-target trials introduces bias in the direction of ABEs, due to the statistical phenomenon of regression toward the mean. We conclude that statistical estimation, possibly coupled with experimental control, offers the most valid and least biased solution.

Pragmatic expectations and linguistic evidence: Listeners anticipate but do not integrate common ground.

When listeners search for the referent of a speaker's expression, they experience interference from privileged knowledge, knowledge outside of their 'common ground' with the speaker. Evidence is presented that this interference reflects limitations in lexical processing. In three experiments, listeners' eye movements were monitored as they searched for the target of a speaker's referring expression in a display that also contained a phonological competitor (e.g., bucket/buckle). Listeners anticipated that the speaker would refer to something in common ground, but they did not experience less interference from a competitor in privileged ground than from a matched competitor in common ground. In contrast, interference from the competitor was eliminated when it was ruled out by a semantic constraint. These findings support a view of comprehension as relying on multiple systems with distinct access to information and present a challenge for constraint-based views of common ground.

Is language processing different in dialogue?

Pickering & Garrod (P&G) claim that the automatic mechanisms that underlie language processing in dialogue are absent in monologue. We disagree with this claim, and argue that dialogue simply provides a different context in which the same basic processes operate.

Limits on theory of mind use in adults.

By 6 years, children have a sophisticated adult-like theory of mind that enables them not only to understand the actions of social agents in terms of underlying mental states, but also to distinguish between their own mental states and those of others. Despite this, we argue that even adults do not reliably use this sophisticated ability for the very purpose for which it is designed, to interpret the actions of others. In Experiment 1, a person who played the role of "director" in a communication game instructed a participant to move certain objects around in a grid. Before receiving instructions, participants hid an object in a bag, such that they but not the director would know its identity. Occasionally, the descriptions that the director used to refer to a mutually-visible object more closely matched the identity of the object hidden in the bag. Although they clearly knew that the director did not know the identity of the hidden object, they often took it as the referent of the director's description, sometimes even attempting to comply with the instruction by actually moving the bag itself. In Experiment 2 this occurred even when the participants believed that the director had a false belief about the identity of the hidden object, i.e. that she thought that a different object was in the bag. These results show a stark dissociation between an ability to reflectively distinguish one's own beliefs from others', and the routine deployment of this ability in interpreting the actions of others. We propose that this dissociation indicates that important elements of the adult's theory of mind are not fully incorporated into the human comprehension system.

Paralinguistic correlates of conceptual structure.

How is conceptual knowledge transmitted during conversation? When a speaker refers to an object, the name that the speaker chooses conveys information about category identity. In addition, I propose that a speaker's confidence in a classification can convey information about category structure. Because atypical instances of a category are more difficult to classify than typical instances, when speakers refer to these instances their lack of confidence will manifest itself "paralinguistically"--that is, in the form of hesitations, filled pauses, or rising prosody. These features can help listeners learn by enabling them to differentiate good from bad examples of a category. So that this hypothesis could be evaluated, in a category learning experiment participants learned a set of novel colors from a speaker. When the speaker's paralinguistically expressed confidence was consistent with the underlying category structure, learners acquired the categories more rapidly and showed better category differentiation from the earliest moments of learning. These findings have important implications for theories of conversational coordination and language learning.