Young infants show unexplained asymmetries in the exclusivity of categories formed on the basis of visually presented stimuli. We describe a connectionist model that shows similar exclusivity asymmetries when categorizing the same stimuli presented to the infants. The asymmetries can be explained in terms of an associative learning mechanism, distributed internal representations, and the statistics of the feature distributions in the stimuli. We use the model to explore the robustness of this asymmetry. The model predicts that the asymmetry will persist when a category is acquired in the presence of mixed category exemplars. A study with 3- to 4-month-olds show that asymmetric exclusivity continues to persist in the presence of a mixed familiarization, thereby corroborating the model's predictions. We suggest that by interpreting asymmetric exclusivity effects as manifestations of interference in an associative memory system, the model can also be extended to account for interference e...

This paper presents a connectionist model of correlation based categorization by 10month -old infants (Younger, 1985). Simple autoencoder networks were exposed to the same stimuli used to test 10-month-olds. The familiarisation regime was kept as close as possible to that used with the infants. The model's performance matched that of the infants. Both infants and networks used co-variation information (when available) to segregate items into separate categories. The model provides a mechanistic account of category learning with a test session. It demonstrates how categorization arises as the product of an inextricable interaction between the subject (the infant) and the environment (the stimuli). The computational characteristics of both subject and environment must be considered in conjunction to understand the observed behaviors. Mechanisms of Categorization in Infancy The ability to categorize underlies much of cognition. It is a way of reducing the load on memory and oth...

An unusual asymmetry has been observed in natural category formation in infants (Quinn, Eimas, and Rosenkrantz, 1993). Infants who are initially exposed to a series of pictures of cats and then are shown a dog and a novel cat, show significantly more interest in the dog than in the cat. However, when the order of presentation is reversed --- dogs are seen first, then a cat and a novel dog --- the cat attracts no more attention than the dog. We show that a simple connectionist network can model this unexpected learning asymmetry and propose that this asymmetry arises naturally from the asymmetric overlaps of the feature distributions of the two categories. The values of the cat features are subsumed by those of dog features, but not vice-versa. The autoencoder used for the experiments presented in this paper also reproduces exclusivity effects in the two categories as well the reported effect of catastrophic interference of dogs on previously learned cats, but not vice-...

for assistance, and Nora Newcombe and Elliott Blass for advice and comments on the manuscript. Above all, I am grateful to Ariel Grace and Kristin Shutts for their unending support and after-hours labor on this project. Draft, 4/20/05. This paper has not yet been peer reviewed. Please do not copy or cite without author's permission. This report considers three prominent claims that boys and men have greater natural aptitude for high-level careers in mathematics and science. According to the first claim, males are more focused on objects and mechanical systems from the beginning of life. According to the second claim, males have a profile of spatial and numerical abilities that predisposes them to greater aptitude in mathematics. According to the third claim, males show greater variability in mathematical aptitude, yielding a preponderance of males at the upper end of the distribution of mathematical talent. Research on cognitive development in human infants and preschool children, and research on cognitive performance by students at all levels, provides evidence against these claims. Mathematical and scientific reasoning develop from a set of biologically based capacities that males and females share. From these capacities, men and women appear to develop equal talent for mathematics and science.

Disentangling bottom-up and top-down processing in adult category learning is notoriously difficult. Studying category learning in infancy provides a simple way of exploring category learning while minimizing the contribution of top-down information. Three- to 4-month-old infants presented with cat or dog images will form a perceptual category representation for cat that excludes dogs and for dog that includes cats. The authors argue that an inclusion relationship in the distribution of features in the images explains the asymmetry. Using computational modeling and behavioral testing, the authors show that the asymmetry can be reversed or removed by using stimulus images that reverse or remove the inclusion relationship. The findings suggest that categorization of nonhuman animal images by young infants is essentially a bottom-up process. Few in cognitive science would dispute the argument that both bottom-up (i.e., perceptually driven) and top-down (i.e., conceptually driven) processes are involved in adult categorization. Numerous studies have discussed the relationship between these two mechanisms of categorization (e.g., French, 1995; Murphy & Kaplan, 2000; Schyns, Goldstone, & Thibaut, 1998). However, in adults, perceptual and conceptual processes are deeply intertwined, making them difficult to isolate and study independently (Goldstone & Barsalou, 1998).

This paper presents a connectionist model of correlationbased categorization by 10-month-old infants (Younger, 1985). Simple autoencoder networks were exposed to the same stimuli used to test 10-month-olds. Both infants and networks used co-variation information (when available) to segregate items into separate categories. The model provides a mechanistic account of category learning within a test session. It shows how distinct categories are developed and demonstrates how categorization arises as the product of an inextricable interaction between the subject (the infant) and the environment (the stimuli). Introduction The ability to categorize underlies much of cognition. It is a way of reducing the load on memory and other cognitive processes (Rosch, 1975). Because of its fundamental role, any developmental changes in the ability of infants to categorize is likely have a significant impact on subsequent cognitive development as a whole. As a result, categorization is one ...

We present a connectionist model of children's developing reliance on object labels as opposed to superficial appearance when making inductive inferences. The model learns to infer a fact about an object based on the object's label (and not percept) even though that fact has never been previously associated with the label. The shift in reliance from perceptual to label information is found to depend on: (a) the presence of a pre-linguistic ability to categorize perceptual information, and (b) the greater variability of percepts than labels The model predicts that children will shift their inductive basis at different ages depending on the perceptual variability of the test categories. This prediction is discussed with respect to studies of children's induction and with particular reference to conflicting results reported in the literature concerning the onset of label use. Introduction This paper presents a connectionist model of the child's developing reliance on objec...

Young infants show unexplained asymmetries in the exclusivity of categories formed on the basis of visually presented stimuli. They will also, on some occasions display retroactive interference when shown a succession of visual stimuli whereas on other occasions no interference is found. We describe a connectionist model that shows similar exclusivity asymmetries when categorising the same stimuli presented to the infants. The model predicts asymmetric retroactive interference when learning two categories sequentially. The asymmetry can be explained in terms of an associative learning mechanism, distributed internal representations, and the statistics of the feature distributions in the stimuli. A study of 3- to 4-month-olds' sequential acquisition of Cat and Dog categories also reveals asymmetric retroactive interference, thereby corroborating the model's prediction. This model exemplifies how unrelated domains can be bridged by shifting the onus of research away from a descriptive co...

There is a wealth of research demonstrating that agents process information with the aid of categories. In this paper we study this phenomenon in two parts. First, we build a model of how experiences are sorted into categories and how categorization affects decision making. Second, in a series of results that partly characterize an optimal categorization, we show that specific biases emerge from categorization. For instance, types of experiences and objects that are less frequent in the population tend to be more coarsely categorized and lumped together. As a result, decision makers make less accurate predictions when confronted with such objects. This can result in discrimination against minority groups even when there is no malevolent taste for discrimination. However, such comparative statics are highly sensitive to the particular situation; optimal categorizations can change in surprising ways. For instance, increasing a group’s population, holding all

There is a wealth of research demonstrating that agents process information with the aid of categories. In this paper we study this phenomenon in two parts. First, we build a model of how experiences are sorted into categories and how categorization affects decision making. Second, in a series of results that partly characterize an optimal categorization, we show that speci c biases emerge from categorization. For instance, types of experiences and objects that are less frequent in the population are more coarsely categorized and more often lumped together. As a result, decision makers make