Generic statements (e.g., “Birds lay eggs”) express generalizations about categories. In this paper, we hypothesized that there is a paradoxical asymmetry at the core of generic meaning, such that these sentences have extremely strong implications but require little evidence to be judged true. Four experiments confirmed the hypothesized asymmetry: Participants interpreted novel generics such as “Lorches have purple feathers” as referring to nearly all lorches, but they judged the same novel generics to be true given a wide range of prevalence (...) levels (e.g., even when only 10% or 30% of lorches had purple feathers). A second hypothesis, also confirmed by the results, was that novel generic sentences about dangerous or distinctive properties would be more acceptable than generic sentences that were similar but did not have these connotations. In addition to clarifying important aspects of generics’ meaning, these findings are applicable to a range of real-world processes such as stereotyping and political discourse. (shrink)

Three issues are raised in this commentary. First, the mapping of semantic information into the different layers could be done in a more realistic way by using the Context layer to represent situational contexts. Second, a way to differentiate category membership information from other property information needs to be considered. Finally, the issue of modal knowledge is raised.

An application of some recent work on the science of generic thought.

The modifier effect refers to the fact that the perceived likelihood of a property in a noun category is diminished if the noun is modified. For example, “Pigs live on farms” is rated as more likely than “Dirty pigs live on farms.” The modifier effect has been demonstrated in many studies, but the underlying cognitive mechanisms are still unclear. This paper reports two series of experiments that jointly point to the conclusion that the modifier effect is the result of a (...) superposition of three cognitive mechanisms: (a) probabilistically softened default inheritance, (b) pragmatic implicatures due to Gricean relevance assumptions, and (c) inference based on world knowledge. We present evidence that the pragmatic effects operate largely on an unconscious level and that their influence can be reduced by changing the presentation format of the cognitive task. (shrink)

In this prcis we focus on phenomena central to the reaction against similarity-based theories that arose in the 1980s and that subsequently motivated the approach to semantic knowledge. Specifically, we consider (1) how concepts differentiate in early development, (2) why some groupings of items seem to form or coherent categories while others do not, (3) why different properties seem central or important to different concepts, (4) why children and adults sometimes attest to beliefs that seem to contradict their direct experience, (...) (5) how concepts reorganize between the ages of 4 and 10, and (6) the relationship between causal knowledge and semantic knowledge. The explanations our theory offers for these phenomena are illustrated with reference to a simple feed-forward connectionist model. The relationships between this simple model, the broader theory, and more general issues in cognitive science are discussed. (shrink)

While generic generalisations have been studied by linguists and philosophers for decades, they have only recently become the focus of concentrated interest by cognitive and developmental psychologists, who propose the generics-as-default view. In this paper we focus on the ‘Generic Overgeneralisation’ (GOG) effect proposed by Leslie and colleagues and the native speaker judgments that have been used to support it, and by extension, the generics-as-default view. We take a step back to look at the history of the GOG effect in (...) order to contextualise it. We review existing experimental evidence and discuss four non-mutually exclusive explanations for the GOG effect: ignorance, subkind interpretation, atypical behaviour of all and quantifier domain restriction. We conclude that a closer look at the semantics and pragmatics of generics and universal quantifiers may provide a more nuanced explanation for the pattern of judgment data than that proposed by the generics-as-default view. (shrink)

Generics have historically proven difficult to analyse using the tools of formal semantics. In this paper, I argue that an influential theory of the meaning of generics due to Sarah-Jane Leslie, the Psychological Theory of Generics, is best interpreted not as a theory of their meaning, but as a theory of the psychological heuristics that we use to judge whether or not generics are true. I argue that Leslie’s methodology is not well-suited to producing a theory of the meaning of (...) generics, since it takes speakers’ judgments at face value and ignores the non-semantic factors that might affect these judgments. Leslie’s theory therefore overfits the data of our linguistic intuitions. I present a reconceptualised version of the Psychological Theory of Generics as a theory of how heuristics affect our judgements of the truth values of generics and discuss the application of this reconceptualised theory to some of the puzzles posed by generics, including their apparent content-sensitivity, their inferential asymmetry and their association with stereotyping and prejudice. (shrink)

We propose a coherence account of the conjunction fallacy applicable to both of its two paradigms. We compare our account with a recent proposal by Tentori et al. : 235–255, 2013) that attempts to generalize earlier confirmation accounts. Their model works better than its predecessors in some respects, but it exhibits only a shallow form of generality and is unsatisfactory in other ways as well: it is strained, complex, and untestable as it stands. Our coherence account inherits the strength of (...) the confirmation account, but in addition to being applicable to both paradigms, it is natural, simple, and readily testable. It thus constitutes the next natural step for Bayesian theorizing about the conjunction fallacy. (shrink)

An application of some recent work on the science of generic thought.

It is a fact that human subjects rate sentences about typical properties such as “Ravens are black” as very likely to be true. In comparison, modified sentences such as “Feathered ravens are black” receive lower ratings, especially if the modifier is atypical for the noun, as in “Jungle ravens are black”. This is called themodifier effect. However, the likelihood of the unmodified statement influences the perceived likelihood of the modified statement: the higher the rated likelihood of the unmodified sentence, the (...) higher the rated likelihood of the modified one. That means the modifier effect does not fully blockdefault inheritanceof typical properties from nouns to modified nouns. This paper discusses this inheritance effect. In particular, I ask whether it is the direct result of composing concepts from nouns, that is, a bias toward “black” when processing “raven”. I report a series of experiments in which I find no evidence for a direct inheritance from composition. This supports the view that default inheritance is rather an inference than a bias. (shrink)

This chapter considers the present account to be a sufficient response to the generality problem as an objection that specifically targets reliabilism. It identifies the main challenge for reliabilism in relation to the typing of belief‐forming processes. The chapter focuses on insights in cognitive science in a way that should make this response attractive to practitioners of naturalized epistemology, including Goldman himself. The most stimulating part of Conee and Feldman's attack can charitably be viewed as targeting the notion that the (...) reliabilist concepts of knowledge and justification are sufficiently similar to their folk counterparts. The chapter focuses for simplicity on the reliabilist theory of justification (RJ) and on Conee and Feldman's criticism as targeting the faithfulness of RJ with regard to everyday concept of justification. For the purposes of neutralizing Conee and Feldman's central challenge it was sufficient to give a purely descriptive account of how people type belief‐forming processes. (shrink)

In this paper, we compare the formal semantics approach to genericity, within which genericity is viewed as a species of quantification, and a growing body of experimental and developmental work on the topic, mainly by psychologists rather than linguists, proposing that genericity is categorically different from quantification. We argue that this generics-as-default hypothesis is much less well supported by evidence than its supporters contend, and that a research program combining theoretical and experimental research methods and considerations in the same studies (...) is required to make progress. (shrink)

Much evidence suggests that, from a young age, humans are able to generalize information learned about a subset of a category to the category itself. Here, we propose that—beyond simply being able to perform such generalizations—people are biased to generalize to categories, such that they routinely make spontaneous, implicit category generalizations from information that licenses such generalizations. To demonstrate the existence of this bias, we asked participants to perform a task in which category generalizations would distract from the main goal (...) of the task, leading to a characteristic pattern of errors. Specifically, participants were asked to memorize two types of novel facts: quantified facts about sets of kind members and generic facts about entire kinds. Moreover, half of the facts concerned properties that are typically generalizable to an animal kind, and half concerned properties that are typically more idiosyncratic. We predicted that—because of the hypothesized bias—participants would spontaneously generalize the quantified facts to the corresponding kinds, and would do so more frequently for the facts about generalizable properties. In turn, these generalizations would lead to a higher rate of quantified-to-generic memory errors for the generalizable properties. The results of four experiments supported this prediction. Moreover, the same generalizable-versus-idiosyncratic difference in memory errors occurred even under cognitive load, which suggests that the hypothesized bias operates unnoticed in the background, requiring few cognitive resources. In sum, this evidence suggests the presence of a powerful bias to draw generalizations about kinds. (shrink)

This paper takes issue with a recent proposal due to Shogenji (Synthese 184:29–48, 2012). In his paper, Shogenji introduces J, a normatively motivated formal measure of justification (and of confirmation), and then proceeds to recruit it descriptively in an explanation of the conjunction fallacy. We argue that this explanation is undermined by the fact that it cannot be extended in any natural way to the inverse conjunction fallacy, a more recently discovered, closely related fallacy. We point out that since the (...) inverse conjunction fallacy occurs in the absence of any form of explicit evidence, formal measures of confirmation such as J, are hard pressed to apply to it at all. We then proceed to argue that this problem with Shogenji’s measure is actually quite difficult to come to terms with; even if the situations where people commit the inverse conjunction fallacy are understood in such a way that the measure is applicable, it doesn’t seem possible to reasonably interpret these situations in such a way that the measure can explain the found response pattern. (shrink)

The principle of compositionality claims that the content of a complex concept is determined by its constituent concepts and the way in which they are composed. However, for prototype concepts this principle is often too rigid. Blurring the division between conceptual composition and belief update has therefore been suggested. Inspired by this idea, we develop a normative account of how belief revision and meaning composition should interact in modifications such as “red apple” or “pet hamster”. We do this by combining (...) the well-known selective modification model :485–527 1988) with the rules of Bayesian belief update. Moreover, we relate this model to systems of defeasible reasoning as discussed in the field of artificial intelligence. (shrink)

This paper addresses theoretical problems arising from the vagueness of language terms, and intuitions of the vagueness of the concepts to which they refer. It is argued that the central intuitions of prototype theory are sufficient to account for both typicality phenomena and psychological intuitions about degrees of membership in vaguely defined classes. The first section explains the importance of the relation between degrees of membership and typicality (or goodness of example) in conceptual categorization. The second and third section address (...) arguments advanced by Osherson and Smith (1997), and Kamp and Partee (1995), that the two notions of degree of membership and typicality must relate to fundamentally different aspects of conceptual representations. A version of prototype theory—the Threshold Model—is proposed to counter these arguments and three possible solutions to the problems of logical selfcontradiction and tautology for vague categorizations are outlined. In the final section graded membership is related to the social construction of conceptual boundaries maintained through language use. (shrink)

This paper raises a principled objection against the idea that Bayesian confirmation theory can be used to explain the conjunction fallacy. The paper demonstrates that confirmation-based explanations are limited in scope and can only be applied to cases of the fallacy of a certain restricted kind. In particular; confirmation-based explanations cannot account for the inverse conjunction fallacy, a more recently discovered form of the conjunction fallacy. Once the problem has been set out, the paper explores four different ways for the (...) confirmation theorist to come to terms with the problem, and argues that none of them are successful. (shrink)

Sorites arguments employ an induction step such as ‘Small numbers have small successors’. People deduce that there must be an exception to the generalization but are reluctant to conclude that the generalization is false. My hypothesis is that the reluctance is due to the "Generic Overgeneralization Effect". Although the propounder of the sorites paradox intends the induction step to be a universal generalization, hearers assimilate universal generalizations to generic generalizations (for instance, ‘All birds fly’ tends to be remembered as ‘Birds (...) fly’). Most generic generalizations tolerate exceptions – especially when those exceptions are rare, abnormal, or difficult to imagine. Any counterexample to the induction step will have all of these features. (shrink)