Sortals for Dummies

Advocates of sortal essentialism have argued that concepts like “thing” or “object” lack the unambiguous individuative criteria necessary to play the role of genuine sortals in reference. Instead, they function as “dummy sortals” which are placeholders or incomplete designations. In disqualifying apparent placeholder sortals, however, these philosophers have posed insuperable problems for accounts of childhood conceptual development. I argue that recent evidence in psychology demonstrates that children do possess simple or basic sortals of physical objects or things. I contend that these concepts provide the genuine individuative criteria necessary for reference. As a consequence, sortalism can be made compatible with the developmental facts of conceptual development.

An algebra of human concept learning

An important element of learning from examples is the extraction of patterns and regularities from data. This paper investigates the structure of patterns in data defined over discrete features, i.e. features with two or more qualitatively distinct values. Any such pattern can be algebraically decomposed into a spectrum of component patterns, each of which is a simpler or more atomic “regularity.” Each component regularity involves a certain number of features, referred to as its degree. Regularities of lower degree represent simpler or more coarse patterns in the original pattern, while regularities of higher degree represent finer or more idiosyncratic patterns. The full spectral breakdown of a pattern into component regularities of minimal degree, referred to as its power series, expresses the original pattern in terms of the regular rules or patterns it obeys, amounting to a kind of “theory” of the pattern. The number of regularities at various degrees necessary to represent the pattern is tabulated in its power spectrum, which expresses how much of a pattern's structure can be explained by regularities of various levels of complexity. A weighted mean of the pattern's spectral power gives a useful numeric summary of its overall complexity, called its algebraic complexity. The basic theory of algebraic decomposition is extended in several ways, including algebraic accounts of the typicality of individual objects within concepts, and estimation of the power series from noisy data. Finally some relations between these algebraic quantities and empirical data are discussed.     

From grammatical number to exact numbers: early meanings of 'one', 'two', and 'three' in English, Russian, and Japanese

This study examined whether singular/plural marking in a language helps children learn the meanings of the words 'one,' 'two,' and 'three.' First, CHILDES data in English, Russian (which marks singular/plural), and Japanese (which does not) were compared for frequency, variability, and contexts of number-word use. Then young children in the USA, Russia, and Japan were tested on Counting and Give-N tasks. More English and Russian learners knew the meaning of each number word than Japanese learners, regardless of whether singular/plural cues appeared in the task itself (e.g., "Give two apples" vs. "Give two"). These results suggest that the learning of "one," "two" and "three" is supported by the conceptual framework of grammatical number, rather than that of integers.     

More than words: A reply to Malt and Sloman

In four experiments, Malt and Sloman [Malt, B. C., & Sloman, S. A. (2007). Category essence or essentially pragmatic? Creator’s intention in naming and what’s really what. Cognition, 105, 615-648] show that the naming of artifacts is affected by discourse context. They see this phenomenon as posing a problem for the intentional-history theory of artifact categorization (e.g., [Bloom, P. (1996). Intention, history, and artifact concepts. Cognition, 60, 1-29]), and as supporting instead their alternative theory that naming is determined by communicative goals. This response begins by distinguishing the problem of artifact categorization (determining the categories that artifacts belong to) from the problem of artifact naming (deciding how to talk about members of these categories). In light of this distinction, it turns out that Malt and Sloman’s findings are fully consistent with all theories of artifact categorization, including the intentional-historical one. Moreover, contrary to what they argue, there are actually many cases where the relative contributions of categorization and pragmatics can be clearly distinguished. Finally, it is argued that Malt and Sloman’s own account of artifact naming presupposes a capacity for artifact categorization; it cannot work without one.     

Differences in preschoolers’ and adults’ use of generics about novel animals and artifacts: A window onto a conceptual divide

Children and adults commonly produce more generic noun phrases (e.g., birds fly) about animals than artifacts. This may reflect differences in participants’ generic knowledge about specific animals/artifacts (e.g., dogs/chairs), or it may reflect a more general distinction. To test this, the current experiments asked adults and preschoolers to generate properties about novel animals and artifacts (Experiment 1: real animals/artifacts; Experiments 2 and 3: matched pairs of maximally similar, novel animals/artifacts). Data demonstrate that even without prior knowledge about these items, the likelihood of producing a generic is significantly greater for animals than artifacts. These results leave open the question of whether this pattern is the product of experience and learned associations or instead a set of early-developing theories about animals and artifacts.     

Contrast effects in typicality judgements: A hierarchical Bayesian approach

We examine the influence of contrast categories on the internal graded membership structure of everyday concepts using computational models proposed in the artificial category learning tradition. In particular, the generalized context model (Nosofsky, 1986), which assumes that only members of a given category contribute to the typicality of a category member, is contrasted to the similarity–dissimilarity generalized context model (SD-GCM; Stewart & Brown, 2005), which assumes that members of other categories are also influential in determining typicality. The models are compared in a hierarchical Bayesian framework in their account of the typicality gradient of five animal categories and six artefact categories. For each target category, we consider all possible relevant contrast categories. Three separate issue are examined: (a) whether contrast effects can be found, (b) which categories are responsible for these effects, and (c) whether more than one category influences the typicality. Results indicate that the internal category structure is codetermined by dissimilarity towards potential contrast categories. In most cases, only a single contrast category contributed to the typicality. The present findings suggest that contrast effects might be more widespread than has previously been assumed. Further, they stress the importance of characteristics particular of everyday concepts, which require careful consideration when applying computational models of representation of the artificial category learning tradition to everyday concepts.     

How surprising is a simple pattern? Quantifying "Eureka!"

Simple patterns are compelling. When all the observed facts fit into a simple theory or "story," we are intuitively convinced that the pattern must be real rather than random. But how surprising is a simple pattern, really? That is, given a pattern of featural data, such as the properties of a set of objects, how unlikely would the pattern be if they were actually generated at random? In conventional statistics dealing with patterns of numbers, this type of question would be answered by reference to a null distribution such as the t distribution. This paper gives the analogous answer in the realm of concept learning, that is, the formation of generalizations from patterns of featural data. Using a formal but psychologically valid definition of complexity, I derive and exhibit the distribution of subjective complexity under the hypothesis of no pattern. This leads directly to a number of applications, including a statistical test indicating whether an observed pattern is sufficiently simple that it is not likely to have been an accident: literally, the "significance of simplicity."     

Six does not just mean a lot: preschoolers see number words as specific

This paper examines what children believe about unmapped number words - those number words whose exact meanings children have not yet learned. In Study 1, 31 children (ages 2-10 to 4-2) judged that the application of five and six changes when numerosity changes, although they did not know that equal sets must have the same number word. In Study 2, 15 children (ages 2-5 to 3-6) judged that six plus more is no longer six, but that a lot plus more is still a lot. Findings support the hypothesis that children treat number words as referring to specific, unique numerosities even before they know exactly which numerosity each word refers to.     

Infants' sensitivity to correlations between static and dynamic features in a category context

Four experiments with the habituation procedure investigated 14-22-month-olds' ability to attend to correlations between static and dynamic features embedded in a category context. In Experiment 1, infants were habituated to four objects that exhibited invariant relations between moving features and motion trajectory. Results revealed that 14-month-olds did not process any independent features, 18-month-olds processed individual features but not relations among features, and 22-month-olds processed relations among features. In Experiment 2, 14-month-olds differentiated all of the features in the events in a simpler discrimination task. In Experiments 3a and 3b, 22-month-olds failed to show sensitivity to correlations between dynamic and static features in a category context. In Experiment 4, 22-month-olds, but not 18-month-olds, generalized the learned feature-motion relation to a novel instance. The results are discussed in relation to infants' developing ability to attend to correlations, constraints on learning, category coherence, and the development of the animate-inanimate distinction.