The effect of negative polarity items on inference verification

The scalar approach to negative polarity item (NPI) licensing assumes that NPIs are allowable in contexts in which the introduction of the NPI leads to proposition strengthening (e.g., Kadmon & Landman 1993, Krifka 1995, Lahiri 1997, Chierchia 2006). A straightforward processing prediction from such a theory is that NPI’s facilitate inference verification from sets to subsets. Three experiments are reported that test this proposal. In each experiment, participants evaluated whether inferences from sets to subsets were valid. Crucially, we manipulated whether the premises contained an NPI. In Experiment 1, participants completed a metalinguistic reasoning task, and Experiments 2 and 3 tested reading times using a self-paced reading task. Contrary to expectations, no facilitation was observed when the NPI was present in the premise compared to when it was absent. In fact, the NPI significantly slowed down reading times in the inference region. Our results therefore favor those scalar theories that predict that the NPI is costly to process (Chierchia 2006), or other, nonscalar theories (Giannakidou 1998, Ladusaw 1992, Postal 2005, Szabolcsi 2004) that likewise predict NPI processing cost but, unlike Chierchia (2006), expect the magnitude of the processing cost to vary with the actual pragmatics of the NPI

Prior knowledge and statistical models of learning

The research reported here describes the effects of prior knowledge on how people form categories and learn continuous mappings. Chapter 2 is a review of the past research on knowledge effects in the statistical and psychological literature. Chapter 3 presents simulations of a set of experiments carried out by Heit and Bott (2000) into how knowledge is selected in a category learning task. The model was shown to account for the results of Heit and Bott and generate several new predictions concerning blocking effects with the use of prior knowledge. However, empirical testing of these predictions failed to demonstrate these effects. Chapter 4 describes work testing Delosh, McDaniel and Busemeyer's (1997) model of function learning, the Extrapolation Associative Learning Model (EXAM). Experiments were carried out demonstrating that a model that assumes only linear extrapolation, such as EXAM, is inadequate as a generic model of function learning. An alternative model to EXAM is presented which is constructed of several components, each module applying different quantities of prior knowledge to the task. Chapter 5 presents experiments investigating the extent to which participants abstract and apply functions in transfer-tasks. The results demonstrate that models of function learning must be able to restrict their range of allowable solutions in psychologically plausible ways

Intonation and pragmatic enrichment: how intonation constrains ad-hoc scalar inferences

Pragmatic inferences require listeners to use alternatives to arrive at the speaker’s intended meaning. Previous research has shown that intonation interacts with alternatives but not how it does so. We present two mouse tracking experiments that test how pitch accents affect the processing of ad hoc scalar implicatures in English. The first shows that L+H* accents facilitate implicatures relative to H* accents. The second replicates this finding and demonstrates that the facilitation is caused by early derivation of the implicature in the L+H* condition. We attribute the effect to a link between L+H* and pragmatic considerations, such as speaker knowledge effects, or the saliency of alternatives relevant to the computation of implicatures. More generally our findings illustrate how intonation interacts at a cognitive level with pragmatic inference

Priming scalar and ad hoc enrichment in children

Sentences can be enriched by considering what the speaker does not say but could have done. Children, however, struggle to derive one type of such enrichments, scalar implicatures. A popular explanation for this, the lexical alternatives account, is that they do not have lexical knowledge of the appropriate alternatives to generate the implicature. Namely, children are unaware of the scalar relationship between some and all. We conducted a priming study with N = 72 children, aged 5;1 years, and an adult sample, N = 51, to test this hypothesis. Participants were exposed to prime trials of strong, alternative, or weak sentences involving scalar or ad hoc expressions, and then saw a target trial that could be interpreted in either way. Consistent with previous studies, children were reluctant to derive scalar implicatures. However, there were two novel findings. (1) Children responded with twice the rate of ad hoc implicature responses than adults, suggesting that the implicature was the developmentally prior interpretation for ad hoc expressions. (2) Children showed robust priming effects, suggesting that children are aware of the scalar relationship between some and all, even if they choose not to derive the implicature. This suggests that the root cause of the scalar implicature deficit is not due to the absence of lexical knowledge of the relationship between some and all

The role of alternative salience in the derivation of scalar implicatures

Comprehension can be enriched by considering what a speaker could have said but did not; namely, the alternative. For example, “Betty passed some of her exams” can be interpreted as “Betty passed some but not all of her exams”. This enriched interpretation is an example of a scalar implicature. We consider whether the salience and use of the alternative are independent processes in the derivation of scalar implicatures or whether use is dependent on salience. Participants completed three sentence interpretation experiments in which the sentences invited scalar implicatures. The experiments used a structural priming paradigm with alternatives and implicatures as primes. We found that (1) adults could be primed to derive scalar implicatures when the alternative was the prime (2) they did so at a rate equal to if the scalar implicature itself were the prime. In the absence of evidence that the use of the alternative can be primed independently of its salience, we conclude that salience and use are not independent processes. Instead, we suggest that when the alternative is sufficiently salient, the implicature will automatically be derived

Salient alternatives facilitate implicatures

Sentences can be enriched by considering what the speaker does not say but could have done, the alternative. We conducted two experiments to test whether the salience of the alternative contributes to how people derive implicatures. Participants responded true or false to underinformative categorical sentences that involved quantifiers. Target sentences were sometimes preceded by the alternative and sometimes by a control sentence. When the target was preceded by the alternative, response times to implicature responses were faster than when preceded by the control sentence. This suggests that (1) alternative salience influences higher-level reasoning (2) the cost of deriving implicatures in sentence verification paradigms is due in part to low alternative salience

Shared and distinct mechanisms in deriving linguistic enrichment

Meanings of basic expressions can be enriched by considering what the speaker could have said, but chose not to, that is, the alternatives. We report three priming experiments that test whether there are shared enrichment mechanisms across a diverse range of linguistic categories. We find that quantifier, number, and ad hoc enrichments exhibit robust priming within their categories and between each other. Plural enrichments, in contrast, demonstrate within-category priming but no between-category priming. Our results demonstrate that (1) enrichment typically thought of as pragmatic or semantic can be primed in the same way as syntactic structures, and (2) there are mechanisms that are shared across different enrichment categories, and that some phenomena (e.g., plurals) are excluded from this class. We discuss the implications of our findings for psychological models of enrichment, theories of individual categories of enrichment, and structural priming

Perceptual similarity in autism

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O’Riordan, and others (Bonnel et al., 2003; O’Riordan & Plaisted, 2001; O’Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O’Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modeled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.peer-reviewe

How people learn features in the absence of classification error

Models of category learning often assume that exemplar features are learned in proportion to how much they reduce classification error. In contrast, experimental evidence suggests that people continue to learn features even when classification is perfect. We present three experiments that test explanations for how people might learn features in the absence of error. In Experiment 1, we varied the type of feedback participants received. In Experiment 2, we introduced a secondary task during the feedback phase, and in Experiment 3, we restricted the response window and varied the feedback. In all cases, we found that participants learn many more features than they need to classify the exemplars. Our results suggest that participants learn the internal correlations between features, rather than directly forming associations between features and the category label. This finding places restrictions on the types of categorisation models that can satisfactorily explain learning in the absence of classification error

The time course of familiar metonymy

Metonymic words have multiple related meanings, such as college, as in the building (“John walked into the college”) or the educational institution (“John was promoted by the college”). Most researchers have found support for direct access models of metonymy but one recent study, Lowder and Gordon (2013), found delayed reading times for metonymic sentences relative to literal controls, in support of an indirect access account. We conducted a speed-accuracy-tradeoff experiment to test whether their result was caused by lower retrieval probabilities, consistent with direct or indirect access models of metonymy, or slower retrieval dynamics, consistent only with indirect access accounts. We found lower retrieval probabilities for the metonymic sentences but no difference in the dynamics parameters. These results therefore suggest that literal senses do not have priority during processing and that established metonymic senses can be accessed directly