Time course of scalars-1 Some utterances are underinformative : The onset and time course of scalar inferences

When Tarzan asks Jane Do you like my friends? and Jane answers Some of them, her underinformative reply implicates Not all of them. This scalar inference arises when a lessthan-maximally-informative utterance implies the denial of a more informative proposition. Default Inference accounts (e.g. Levinson, 1983; 2000) argue that this inference is linked to lexical items (e.g. some) and is generated automatically and largely independently of context. Alternatively, Relevance Theory (Sperber and Wilson, 1986/1995) treats such inferences as contextual and as arriving effortfully with deeper processing of utterances. We compare these accounts in four experiments that employ a sentence verification paradigm. We focus on underinformative sentences, such as Some elephants are mammals, because these are false with a scalar inference and true without it. Experiment 1 shows that participants are less accurate and take significantly longer to answer correctly when instructions call for a Some but not all interpretation rather than a Some and possibly all interpretation. Experiment 2, which modified the paradigm of Experiment 1 so that correct responses to both interpretations resulted in the same overt response, reports results that confirm those of the first Experiment. Experiment 3, which imposed no interpretations, reveals that those who employed a Some but not all reading to the underinformative items took longest to respond. Experiment 4 shows that the rate of scalar inferences increased as a permitted response time did. These results argue against a neo-Gricean account and in favor of Relevance theory. Time course of scalars -3 There is a growing body of psycholinguistic work that focuses on the comprehension of logical terms. These studies can be broken down into two sets. One investigates the way logical inferences are made on-line in the context of story comprehension (e.g. Lea, O'Brien, Fisch, Noveck, & et al., 1990; Lea, 1995) . In this approach, the comprehension of a term like or is considered to be tantamount to knowing logical inference schemas attached to it. For or it would be or-elimination (where the two premises p or q; not-q – imply p). The other line of research investigates non-standard existential quantifiers, such as few or a few, demonstrating how the meanings of quantifiers besides conveying notions about amount transmit information about the speaker’s prior expectations as well as indicate where the addressee ought to place her focus (Moxey, Sanford, & Dawydiak, 2001; Paterson, Sanford, Moxey, & Dawydiak, 1998, Sanford, Moxey, & Paterson, 1996). For example, positive quantifiers like a few, put the focus on the quantified objects (e.g. those who got to the match in A few of the fans went to the match) while negative quantifiers like few place the focus on the quantified objects’ complement (e.g. those fans who did not go to the match in Few of the fans went to the match). In the present paper, we investigate a class of inference which we will refer to as a scalar inference that is orthogonal to the ones discussed above, but is arguably central to the way listeners treat logical terms. These arise when a less-than-maximally-informative utterance is taken to imply the denial of the more informative proposition (or else to imply a lack of knowledge concerning the more informative one). Consider the following dialogues: 1) Peter: Are Cheryl and Tony coming for dinner? Jill: We are going to have Cheryl or Tony. Time course of scalars -4 2) John: Did you get to meet all of my friends? Robyn: Some of them. In (1), Jill’s statement can be taken to mean that not both Cheryl and Tony are coming for dinner and, in (2), that Robyn did not meet all of John’s friends. These interpretations are the result of scalar inferences, which we will describe in detail below. Before we do so, note that the responses in each case are compatible with the questioner’s stronger expectation from a strictly logical point of view; if Jill knows that both Cheryl and Tony are coming, her reply is still true and if in fact Robyn did meet all of John’s friends, she also spoke truthfully. Or is logically compatible with and and some is logically compatible with all. Linguistic background Scalar inferences are examples of what Paul Grice (1989) called generalized implicatures as he aimed to reconcile logical terms with their non-logical meanings. Grice, who was especially concerned by propositional connectives, focused on logical terms that become, through conversational contexts, part of the speaker’s overall meaning. In one prime example, he described how the disjunction or has a weak sense, which is compatible with formal logic’s ∨ (the inclusive-or), but as benefiting from a stronger sense (but not both) through conversational uses (making the disjunction exclusive). What the disjunction says, he argued, is compatible with the weaker sense, but through conversational principles it often means the stronger one. Any modern account of the way logical terms are understood in context would not be complete without considering these pragmatic inferences. Grice’s generalized implicatures were assumed to occur very systematically although the context may be such that they do not occur. These were contrasted with particularized implicatures, which were assumed to be less systematic and always clearly context Time course of scalars -5 dependent. His reasons for making the distinction had to do with his debates with fellow philosophers on the meaning of logical connectives and of quantifiers, and not with the goal of providing a processing model of comprehension, and there is some vagueness in his view of the exact role of the context in the case of generalized implicatures (see Carston, 2002, pages 107-116). In summary, Grice can be said to have inspired work on implicatures (by providing a framework), but there is not enough in the theory to describe, for example, how a scalar inference manifests itself in real time. Pragmatic theorists, who have followed up on Grice and are keen on describing how scalar inferences actually work, can be divided into two camps. On the one hand, there are those who assume that the inference generally goes through unless subsequently cancelled by the context. That is, scalars operate on the (relatively weak) terms the speaker’s choice of a weak term implies the rejection of a stronger term from the same scale. To elucidate with disjunctions, the connectives or and and may be viewed as part of a scale (<or, and>), where and constitutes the more informative element of the scale (since p and q entails p or q). In the event that a speaker chooses to utter a disjunctive sentence, p or q, the hearer will take it as suggesting that the speaker either has no evidence that a stronger element in the scale, i.e. p and q, holds or that she perhaps has evidence that it does not hold. Presuming that the speaker is cooperative and well informed the hearer will tend to infer that it is not the case that p and q hold, thereby interpreting the disjunction as exclusive. A strong default approach has been defended by Neo-Griceans like Levinson (2000) and to some extent by Horn (1984, page 13). More recently, Chierchia (in press) and colleagues (Chierchia, Guasti, Gualmini, Meroni, and Crain, 2001) have essentially defended the strong default view by making a syntactic distinction with respect to scalar terms: When a scalar is embedded in a downward-entailing context (e.g. negations and question forms), Chierchia and colleagues predict that one would Time course of scalars -6 not find the production of scalar inferences (also see Noveck et al., 2002). Otherwise, Chierchia and colleagues do assume that scalar inferences go through. For the sake of exposition, we focus on Levinson (2000) because he has provided the most extensive proposal for the way pragmatically enriched “default” or “preferred” meanings of weak scalar terms are put in place. Scalars are considered by Levinson to result from a Q-heuristic, dictating that “What isn’t said isn’t (the case).” It is named Q because it is directly related to Grice’s (1989) first maxim of quantity: Make your utterance as informative as is required. In other words, this proposal assumes that scalars are general and automatic. When one hears a weak scalar term like or, some, might etc. the default assumption is that the speaker knows that a stronger term from the same scale is not warranted or that she does not have enough information to know whether the stronger term is called for. Default means that relatively weak terms prompt the inference automatically or becomes not both, some becomes some but not all etc. Also, a scalar inference can be cancelled. If this happens, it occurs subsequent to the production of the scalar term. On the other hand, there are pragmatists who argue against the default view and in favor of a more contextual account. Such an account assumes that an utterance can be inferentially enriched in order to better appreciate the speaker’s intention, but this is not done on specific words as a first step to arrive at a default meaning. We focus on Relevance Theory because it arguably presents the most extensive contextualist view of pragmatic inferences in general and of scalar inferences in particular (see Post face of Sperber and Wilson, 1995). According to this account, a scalar is but one example of pragmatic inferences which arise when a speaker intends and expects a hearer to draw an interpretation of an utterance that is relevant enough. How far the hearer goes in processing an utterance’s meaning is governed by principles concerning effect and effort; namely, listeners try to gain as many effects as possible for the least effort. Time course of scalars -7 A non-enriched interpretation of a scalar term (the one that more closely coincides with the word’s meaning) could very well lead to a satisfying interpretation of this term in an utterance. Consider Some m