The representation of inherent properties.

Research on the representation of generic knowledge suggests that inherent properties can have either a principled or a causal connection to a kind. The type of connection determines whether the outcome of the storytelling process will include intuitions of inevitability and a normative dimension and whether it will ground causal explanations.

Are formal explanations mere placeholders or pointers?

Formal explanations - explanations that explain properties of a thing by reference to what the thing is, for example, Fido has four legs because he is a dog, appear to be tautological and have led researchers to ask why they are produced. One proposal is that they function as placeholders or pointers to explanations. According to the Placeholders and Pointers as Additional Functions (PPAF) hypothesis, formal explanations are explanatory in and of themselves, and the placeholder and pointer functions are additional functions of formal explanations. In contrast, the Merely Placeholders and Pointers (MPP) hypothesis holds that formal explanations are not explanatory in and of themselves but are placeholders for, or pointers to, explanatory structures. Four experiments compared formal explanations to responses that are uncontroversially tautological and to responses that uncontroversially serve as placeholders for inherent explanations without providing an explanation. The results suggest that formal explanations are not understood to be tautologies, and that, unlike inherent explanation placeholders, formal explanations are selective in the features they target, and apply across content domains. These results are consistent with the PPAF and suggest that formal explanations involve a mode of explanation that is distinct from the mode of explanation involved in inherent explanation. Implications for conceptual representation are discussed.

The physical basis of conceptual representation - An addendum to.

Gallistel (2020) argues that current research on the physical basis of memory assumes an associationistic approach and thus fails to provide an account of quantitative facts because quantitative facts cannot be sensed and have no qualia. But are these approaches any better suited for investigating how we store concepts of concrete things such as dogs, tables and sand, which clearly have qualia? Seven examples of the abstract quantitative and non-quantitative formal structure found in the conceptual representation of concrete things are used to show that Gallistel's critique clearly extends to the conceptual representations stored in semantic memory. Gallistel (2020) presents compelling arguments that the physical basis for quantitative facts will not be the synapse or cell assemblies, but the information-bearing molecules inside the neuron. Given that quantitative facts are intrinsic to even our simplest conceptual representations, we should expect the same for conceptual representations.

The Formal Structure of Kind Representations.

Kind representations, concepts like table, triangle, dog, and planet, underlie generic language. Here, we investigate the formal structure of kind representations-the structure that distinguishes kind representations from other types of representations. The present studies confirm that participants distinguish generic-supporting properties of individuals (e.g., this watch is made of steel) and accidental properties (e.g., this watch is on the nightstand). Furthermore, work dating back to Aristotle establishes that only some generic-supporting properties bear a principled connection to the kind, that is, are true of an individual by virtue of its being a member of a specific kind (e.g., telling time for a watch). The present studies tested the hypothesis that principled connections are part of the formal structure of kind representations. Specifically, they tested whether they structure a newly learned kind representation. Experiment 1 found that introducing a property of a newly encountered novel kind in any one of four linguistic frames that provide evidence that a property has a principled connection to a kind (e.g., "It has fur because it is a blick") led participants to infer a different conceptual consequence of principled connections (i.e., "There is something wrong with this blick, which does not have fur") for which they had no direct evidence. Two introduction frames that provided no evidence for principled connections (e.g., "Almost all blicks have fur") did not generate the same consequence. Experiment 2 found that all of the targeted properties were generic licensing, irrespective of the introduction frame. That the distinction between properties that bear principled connections to their kinds, and merely generic-supporting properties structures novel kind representations, provides strong evidence that this distinction is part of the formal structure of kind representations.

Representation of principled connections: a window onto the formal aspect of common sense conception.

Nominal concepts represent things as tokens of types. Recent research suggests that we represent principled connections between the type of thing something is (e.g., DOG) and some of its properties (k-properties; e.g., having four legs for dogs) but not other properties (t-properties; e.g., being brown for dogs). Principled connections differ from logical, statistical, and causal connections. Principled connections license (i) the expectation that tokens of the type will generally possess their k-properties, (ii) formal explanations (i.e., explanation of the presence of k-properties in tokens of a type by reference to the type of thing it is), and (iii) normative expectations concerning the presence of k-properties in tokens of the type. The present paper investigates the hypothesis that representing principled connections requires representing properties as aspects of being the relevant kind of thing (Aspect Hypothesis). Experiment 1 provides a direct test of the Aspect Hypothesis. Experiments 2 and 3 provide indirect tests of the Aspect Hypothesis. All three experiments provide support for the Aspect Hypothesis. Experiment 4 investigates a prediction of the Aspect Hypothesis concerning the manner in which formal explanations are licensed by principled connections. Finally, Experiment 5 investigates a prediction of the Aspect Hypothesis concerning the nature of the normative expectations licensed by principled connections. Together these results provide strong evidence for the idea that representing principled connections involves representing a property as being an aspect of being a given kind of thing. The results also help clarify the manner in which formal explanation differs from other modes of explanation. Finally, the results of the experiments are used to motivate a proposal concerning the formal structure of the conceptual representations implicated by principled connections. This structure provides a domain-general way of structuring our concepts and embodies the perspective we take when we think and talk of things as being instances of a kind.

Instance-of-object-kind representations.

We naturally think and talk about the objects we encounter as instances of one or another kind of object (e.g. as a dog). This paper makes a proposal concerning the instance-of-object-kind representations that allow us to think of things as instances of object kinds and investigates two predictions of the proposed representations. Instance-of-object-kind representations represent an object as one of indefinitely many instances of a given object kind. In so doing, they implicate a uniqueness-in-kind constraint which represents an object as unique within a kind, by distinguishing the instance-of-object-kind representation of an object from instance-of-object-kind representations of other actually as well as potentially existing instances of that object kind. The uniqueness-in-kind constraint predicts that a given instance of an object kind cannot be transformed into a different potentially existing instance of the same kind, but allows the object to be transformed into a potentially existing instance of a different object kind. Instance-of-object-kind representations also implicate a mode-of-existence constraint whereby actually existing instances of an object kind are represented as being distinct from all actually existing instances of that kind and other object kinds. This constraint predicts that participants should reject the possibility of transforming an actually existing instance of an object kind into an actually existing instance of the same or different object kind. Five experiments provide evidence for these constraints. In so doing, the experiments provide evidence for the formal characteristics of the proposed instance-of-object-kind representations that guide our thinking about things as instances of object kinds.

The development of principled connections and kind representations.

Kind representations draw an important distinction between properties that are understood as existing in instances of a kind by virtue of their being the kind of thing they are and properties that are not understood in this manner. For example, the property of barking for the kind dog is understood as being had by dogs by virtue of the fact that they are dogs. These properties are said to have a principled connection to the kind. In contrast, the property of wearing a collar is not understood as existing in instances by virtue of their being dogs, despite the fact that a large percentage of dogs wear collars. Such properties are said to have a statistical connection to the kind. Two experiments tested two signatures of principled connections in 4-7 year olds and adults: (i) that principled connections license normative expectations (e.g., we judge there to be something wrong with a dog that does not bark), and (ii) that principled connections license formal explanations which explain the existence of a property by reference to the kind (e.g., that barks because it is a dog). Experiment 1 showed that both the children and adults have normative expectations for properties that have a principled connection to a kind, but not those that have a mere statistical connection to a kind. Experiment 2 showed that both children and adults are more likely to provide a formal explanation when explaining the existence of properties with a principled connection to a kind than properties with statistical connections to their kinds. Both experiments showed no effect of age (over ages 4, 7, and adulthood) on the extent to which participants differentiated principled and statistical connections. We discuss the implications of the results for theories of conceptual representation and for the structure of explanation.

The scope of formal explanation.

The existence of multiple modes of explanation means that a crucial step in the process of generating explanations has to be selecting a particular mode. The present article identifies the key conceptual, as well as some pragmatic and epistemological, considerations that license the use of the formal mode of explanation, and thus that enter into the process of selecting and generating a formal explanation. Formal explanations explain the presence of certain properties in an instance of a kind by reference to the kind of thing it is (e.g. That has four legs because it is a dog). As such, this mode of explanation is intrinsically tied to kind representations and is applicable domain-generally. Although it is possible for formal explanation to apply domain-generally, for any given kind it is selective in its application, in that it can explain some, but not all, properties of the instances of a kind. It also appears that different types of properties can receive formal explanations across different domains. This article provides a sketch of a theory of the selectivity of formal explanation that results from the manner in which kinds of different types are distinguished. The present discussion also suggests how the mechanisms underlying formal explanations may contribute to the illusion of explanatory depth Keil (Trends in Cognitive Sciences, 7, 368-373,2003), the operation of the inherence heuristic Cimpian & Salomon (Behavioral and Brain Sciences, 37, 461-480, 2014a; Behavioral and Brain Sciences, 37, 506-527,2014b), and psychological essentialism (Gelman, 2003).

Principled and statistical connections in common sense conception.

Nominal concepts represent things as tokens of types. We report six experiments that investigate the nature of the relations we represent between the type of thing something is (e.g. DOG) and its other properties. The experiments provide evidence that we represent principled connections between the type of thing something is (e.g. DOG) and some of its properties (k-properties; e.g. having four legs for dogs), but not other properties (t-properties; e.g. being brown for dogs). Principled connections are different from logical, statistical, and causal connections. Principled connections, (i) license the expectation that tokens of the type will generally possess the k-property, (ii) license explanation of the presence of k-properties in tokens of a type by reference to the type of thing it is, and (iii) license normative expectations concerning the presence of the k-property in tokens of the type. The experiments provide evidence for all three of these aspects of principled connections. The experiments also demonstrate that principled connections must be distinguished from merely strong statistical connections. We suggest that principled connections are one of the fundamental types of relations (in addition to logical, statistical, and causal relations) in terms of which our conceptual knowledge is structured. We argue that principled connections reveal a formal mode of understanding and explanation. This mode of understanding complements other modes of understanding that have been studied within the theory-based approach to conceptual representation. Finally, we suggest that kind representations are distinguished from representations of mere types by the representation of principled connections to k-properties.

Conceiving of entities as objects and as stuff.

What is the difference between conceiving of an entity as an object of some kind and conceiving of it as an amount of solid stuff? We propose that the difference lies in how one thinks about the entity's structure. Object construals require thinking of the structure as being nonarbitrary, whereas substance construals require thinking of the structure as being arbitrary. We report six experiments that provide empirical support for this proposal. Regularity of structure, repetition of structure, and the existence of structure-dependent functions, all of which provide reasons to consider the structure of an entity to be nonarbitrary, were shown to bias participants towards object construals. We also discuss how the proposed account of what it means to construe an entity as an object or as some stuff can account for a range of findings in the literature on lexical development. These include the relation between cohesiveness and ontological category, shape and ontological category, and complexity of shape and ontological category. Finally, we discuss the nature of construals and the relation of object and substance construals to the physical, design, and intentional stances.

Dual character concepts and the normative dimension of conceptual representation.

Five experiments provide evidence for a class of 'dual character concepts.' Dual character concepts characterize their members in terms of both (a) a set of concrete features and (b) the abstract values that these features serve to realize. As such, these concepts provide two bases for evaluating category members and two different criteria for category membership. Experiment 1 provides support for the notion that dual character concepts have two bases for evaluation. Experiments 2-4 explore the claim that dual character concepts have two different criteria for category membership. The results show that when an object possesses the appropriate concrete features, but does not fulfill the appropriate abstract value, it is judged to be a category member in one sense but not in another. Finally, Experiment 5 uses the theory developed here to construct artificial dual character concepts and examines whether participants react to these artificial concepts in the same way as naturally occurring dual character concepts. The present studies serve to define the nature of dual character concepts and distinguish them from other types of concepts (e.g., natural kind concepts), which share some, but not all of the properties of dual character concepts. More broadly, these phenomena suggest a normative dimension in everyday conceptual representation.

Conceptual distinctions amongst generics.

Generic sentences (e.g., bare plural sentences such as "dogs have four legs" and "mosquitoes carry malaria") are used to talk about kinds of things. Three experiments investigated the conceptual foundations of generics as well as claims within the formal semantic approaches to generics concerning the roles of prevalence, cue validity and normalcy in licensing generics. Two classes of generic sentences that pose challenges to both the conceptually based and formal semantic approaches to generics were investigated. Striking property generics (e.g. "sharks bite swimmers") are true even though only a tiny minority of instances have the property and thus pose obvious problems for quantificational approaches, and they also do not seem to characterize kinds in terms of the principled or statistical connections investigated in previous research (Prasada & Dillingham, 2006, 2009). The second class -minority characteristic generics (e.g. "ducks lay eggs") - also poses serious problems for quantificational accounts, and appears to involve principled connections even though fewer than half of its instances have the relevant property. The experiments revealed three principal discoveries: first, striking generics involve neither principled nor statistical connections. Instead, they involve a causal connection between a kind and a property. Second, minority characteristic generics exhibit the characteristics of principled connections, which suggests that principled connections license the expectation that most instances will have the property, but do not require it. Finally, the experiments also provided evidence that prevalence and the acceptability of generics may be dissociated and provided data that are problematic for normalcy approaches to generics, and for the idea that cue validity licenses low prevalence generics. As such, the studies provided evidence in favor of a conceptually based approach to the semantics of generics (Leslie, 2007, 2008; see also Carlson, 2009).

Conceptual and linguistic representations of kinds and classes.

We investigate the hypothesis that our conceptual systems provide two formally distinct ways of representing categories by investigating the manner in which lexical nominals (e.g., tree, picnic table) and phrasal nominals (e.g., black bird, birds that like rice) are interpreted. Four experiments found that lexical nominals may be mapped onto kind representations, whereas phrasal nominals map onto class representations but not kind representations. Experiment 1 found that phrasal nominals, unlike lexical nominals, are mapped onto categories whose members need not be of a single kind. Experiments 2 and 3 found that categories named by lexical nominals enter into both class inclusion and kind hierarchies and thus support both class inclusion (is a) and kind specification (kind of) relations, whereas phrasal nominals map onto class representations which support only class inclusion relations. Experiment 4 showed that the two types of nominals represent hierarchical relations in different ways. Phrasal nominals (e.g., white bear) are mapped onto classes that have criteria of membership in addition to those specified by the class picked out by the head noun of the phrase (e.g., bear). In contrast, lexical nominals (e.g., polar bear) specify one way to meet the criteria specified by the more general kind concept (e.g., bear). Implications for the language-conceptual system interface, representation of hierarchical relations, lexicalization, and theories of conceptual combination are discussed.

Direct object predictability: effects on young children's imitation of sentences.

We hypothesize that the conceptual relation between a verb and its direct object can make a sentence easier ('the cat is eating some food') or harder ('the cat is eating a sock') to parse and understand. If children's limited performance systems contribute to the ungrammatical brevity of their speech, they should perform better on sentences that require fewer processing resources: children should imitate the constituents of sentences with highly predictable direct objects at a higher rate than those from sentences with less predictable objects. In Experiment 1, 24 two-year-olds performed an elicited imitation task and confirmed that prediction for all three major constituents (subject, verb, direct object). In Experiment 2, 23 two-year-olds performed both an elicited imitation task and a sticker placement task (in which they placed a sticker on the pictured subject of the sentence after hearing and imitating the sentence). Children imitated verbs more often from predictable than unpredictable sentences, but not subjects or objects. Children's inclusion of constituents is affected by the conceptual relations among those constituents as well as by task characteristics.

Singular or plural? Children's knowledge of the factors that determine the appropriate form of count nouns.

Two experiments investigated the factors that govern children's use of singular and plural forms of count nouns. Experiment 1 used an elicited production task to investigate whether children use referential and/or syntactic information to determine the form of the count nouns when the two sources of information conflict (e.g. each x, one of the xs), as well as when the linguistic context does not provide any constraint on the form of the noun, but the referential context does (e.g. the dog(s)). 48 children, aged 1;9 to 5;6, participated in Experiment 1. The results suggest that even the youngest children can use referential information when relevant, and can ignore referential information when necessary. Children did, however, show a tendency to make errors with the quantifier each in non-partitive contexts, and a developmental trend was found in the use and avoidance of each in non-partitive contexts. Experiment 2, an act out task, provided a second test of the role of referential information in children's use of singular and plural forms. Experiment 2 also investigated children's appreciation of the semantic distinction between each and all. 48 children, aged 1;8 to 5;6, participated in Experiment 2. A weak sensitivity to the semantic distinction between the two quantifiers as well as the syntactic context in which they were used was found. The results of the two experiments suggest that, from the beginning, children approach the task of learning when to use singular and plural forms of count nouns on the basis of morphosyntactic, semantic, and referential properties of utterances, rather than initially using only one of these types of information.