Category Learning

Categorization and Reinforcement Learning: State Identification in Reinforcement Learning and Network Reinforcement Learning

by Vladislav "Dan" Veksler

An ERP Analysis of Recognition and Categorization Decisions in a Prototype-Distortion Task

by Richard Tunney

Episodic and prototype models of category learning

by Richard Tunney

Category training affects colour discrimination but only in the RVF

by Alexandra Clifford

Drivonikou, G.V., Clifford, A., Franklin, A. & Davies, I.R.L. (2011). Category training affects colour discrimination but only in the right visual field. In C.P. Biggam, C. Hough, C.J., Kay, & D.R.C. Simmons (Eds.), Progress in Colour Studies: New Directions in Colour Studies. Amsterdam, NL: John Benjamins.

There is indirect evidence that categorical colour perception (better discrimination of colours from different... more There is indirect evidence that categorical colour perception (better discrimination of colours from different categories than those from the same category — CP) can be learned. For instance, CP can be induced across a newly learned category boundary (Özgen & Davies, 2002). Here we replicate and extend Özgen and Davies’s category learning study, to try and pinpoint the nature of the changes underlying category learning. Participants learned to divide green into two new categories ‘yellow-green’ / ‘blue-green’ across four days. The trained group showed CP across the new boundary on a target detection task and this was restricted to the left hemisphere (LH; cf. Drivonikou et al. 2007), whereas the controls did not. The results could suggest that category training produces changes at early stages in visual processing mainly in the LH.

The modulating influence of category size on the classification of exception patterns

by Michael Proulx

Event-related potential correlates of perceptual and functional categories: Comparison between stimuli matching by identity and equivalence

by Angel Tabullo

Event-related potentials (ERPs) correlates of two test criteria of an abstract category taskwere dissociated.
In... more Event-related potentials (ERPs) correlates of two test criteria of an abstract category taskwere dissociated.
In a stimulus equivalence task, 10 subjects observed pairs of figures presented serially in three conditions:
reflexivity (generalized identity), equivalence (arbitrary derived relations from a previous training), and
unrelated pairs. Theywere instructed to decide whether the second itemin a pair matched or mismatched
the first one. Participants’ performance in reflexivity matching tests was faster and more accurate than in
equivalence matching or mismatching responses. In the three conditions, an occipital P2, a frontalN2and a
parietal P3 ERPcomponentwere elicited. The earliercomponents P2 andN2exhibited reflexivity matching
effects, while the later component (P3) exhibited the only equivalence matching effect. In addition, the
subtracted ERP components from unrelated minus identity and unrelated minus equivalence trials were
computed within two time windows: 150–250ms (dN300) and 350–450ms (dN400). While both dN300
waveswere not significantly different, thecomparison of both dN400waves showed statistical differences.
Correlates of partially perceptual (but contextually abstract) concepts are elicited earlier than those of pure
abstract concepts. These ERPs correlates of stimulus equivalence relation tests of semantic categories are
in concordance with the behavioral data.

The law of large numbers in children's diversity-based reasoning

by Gedeon Deák

Li, F., Cao, B., Li, Y., Li, H. & Deák, G., (2009). The law of large numbers in children’s diversity-based reasoning. Thinking and Reasoning, 15, 388-404.

Adults increase the certainty of their inductive inferences by observing more diverse instances. However, most young... more Adults increase the certainty of their inductive inferences by observing more diverse instances. However, most young children fail to do so. The present study tested the hypothesis that children’s sensitivity to instance diversity is determined by three variables: ability to discriminate among instances (Discrimination); an intuition that large numbers of instances increase the strength of conclusion (Monotonicity); ability to detect subcategories and evaluate numerical differences between the subcategories, or Extraction. A total of 219 Chinese children aged 6 to 11 were tested for sensitivity to diversity by means of Discrimination, Monotonicity, and Extraction. The results indicated that children at all ages were able to discriminate instances and attend to set size. However, only 9- and 11-year-olds demonstrated Extraction and sensitivity to diversity. Furthermore, among all children diversity scores increased linearly with the level of Extraction. These results suggest that the law of large numbers plays a role in children’s diversity-based reasoning.

The Effects of Task Comprehension on Preschoolers′ and Adults′ Categorization Choices

by Gedeon Deák

Deák, G. & Bauer, P.J. (1995). The effects of task comprehension on preschoolers' and adults' categorization choices. Journal of Experimental Child Psychology, 60, 393-427.

In experimental tasks in which subjects sort sets of objects with conflicting appearances and taxonomic relations,... more In experimental tasks in which subjects sort sets of objects with conflicting appearances and taxonomic relations, preschoolers often have been found to categorize according to appearance. The procedures used in past studies, however, may have biased preschoolers to attend to appearance instead of taxonomic relations. This possibility was examined in two experiments. In Experiment 1, children′s preference for taxonomic- or appearance-based sorting was affected by both the training and the instructions they received. Adults in Experiment 1 were affected by instructions, but not by training. In Experiment 2 preschoolers sorted above chance according to the criterion for which they received training and instruction (taxonomic relations or appearance). Consistency data, children′s justifications, and spontaneous labeling support the conclusions that training and instructions have a significant effect on children′s preference to sort according to taxonomic relations or appearance, and that both criteria can be used systematically by children as young as four. Implications for task comprehension, flexibility, methodology, and education are discussed.

The dynamics of preschoolers' categorization choices

by Gedeon Deák

Deák, G. & Bauer, P.J. (1996). The dynamics of preschoolers' categorization choices. Child Development, 67, 740-767.

Mather, E. and Plunkett, K. (2011). Same items, different order: Effects of temporal variability on infant categorization. Cognition, 119(3), 438 - 447.

by Emily Mather

Why Johnny Can't Name His Colors

by Melody Dye

Scientific American Mind, Mind Matters Column. July 2010.

No, the kid's probably not color blind. A trick for teaching children colors at a younger age - and why it's otherwise... more No, the kid's probably not color blind. A trick for teaching children colors at a younger age - and why it's otherwise so hard for them.

No Representation Without Taxation: The Costs and Benefits of Learning to Conceptualize the Environment

by Melody Dye

Ramscar, M., Dye, M & Yarlett, D. (Under Review) No Representation without Taxation.

How do the ways in which we learn influence our cognitive representations of what we learn? We show that in language... more How do the ways in which we learn influence our cognitive representations of what we learn? We show that in language learning tasks, the process of learning to conceptualize and categorize perceptual input shapes how that input gets represented in mind. In representation, there seems to be a give and take between veridicality and completeness, on the one hand, and discrimination and accurate categorization, on the other. Learning to better discriminate objects into categories by learning to value salient features makes people less likely to notice or remember the same objects' other features. Gains in responsediscrimination between categories thus come at a cost to within category discrimination. This is a natural consequence of error-driven learning, a mechanism underlying most contemporary learning models. We present an exposition of error-driven learning, outline its implications for cognitive representations, and test these predictions, showing that the patterns of human learning are consistent with our analysis. We suggest that the mechanisms of human learning obey a simple principle: there can be no representation without taxation. We describe the implications of this principle for our conception of categorization and analogy.

The Enigma of Number: Why Children Find the Meanings of Even Small Number Words Hard to Learn and How We Can Help Them Do Better

by Melody Dye

Ramscar M, Dye M, Popick HM, O'Donnell-McCarthy F (2011) The Enigma of Number: Why Children Find the Meanings of Even Small Number Words Hard to Learn and How We Can Help Them Do Better. PLoS ONE 6(7): e22501. doi:10.1371/journal.pone.0022501

Although number words are common in everyday speech, learning their meanings is an arduous, drawn-out process for most... more Although number words are common in everyday speech, learning their meanings is an arduous, drawn-out process for most children, and the source of this delay has long been the subject of inquiry. Children begin by identifying the few small numerosities that can be named without counting, and this has prompted further debate over whether there is a specific, capacity-limited system for representing these small sets, or whether smaller and larger sets are both represented by the same system. Here we present a formal, computational analysis of number learning that offers a possible solution to both puzzles. This analysis indicates that once the environment and the representational demands of the task of learning to identify sets are taken into consideration, a continuous system for learning, representing and discriminating set-sizes can give rise to effective discontinuities in processing. At the same time, our simulations illustrate how typical prenominal linguistic constructions (“there are three balls”) structure information in a way that is largely unhelpful for discrimination learning, while suggesting that postnominal constructions (“balls, there are three”) will facilitate such learning. A training-experiment with three-year olds confirms these predictions, demonstrating that rapid, significant gains in numerical understanding and competence are possible given appropriately structured postnominal input. Our simulations and results reveal how discrimination learning tunes children's systems for representing small sets, and how its capacity-limits result naturally out of a mixture of the learning environment and the increasingly complex task of discriminating and representing ever-larger number sets. They also explain why children benefit so little from the training that parents and educators usually provide. Given the efficacy of our intervention, the ease with which it can be implemented, and the large body of research showing how early numerical ability predicts later educational outcomes, this simple discovery may have far-reaching consequences.

For the price of a song: how pitch category learning comes at a cost to absolute frequency information.

by Melody Dye

Ramscar, M., Suh, E., & Dye, M. (Under Review) For the price of a song: how pitch category learning comes at a cost to absolute frequency information.

Appreciating music is cognitively demanding: listeners must learn to divide a continuous space of sound into... more Appreciating music is cognitively demanding: listeners must learn to divide a continuous space of sound into culturally defined, discrete categories, and maintain a high degree of accuracy in their representations of those sounds. Here, we present a formal analysis of pitch category learning that reveals the trade-offs associated with learning the relative pitch categories that make music possible. Consistent with this, an empirical study reveals how under normal circumstances, people’s ability to represent absolute frequency information is lost as a consequence of the learning processes that facilitate relative pitch acquisition, a finding which may help explain the rarity of absolute pitch among the general population. Understanding the contradictory computational demands of conceptual and perceptual learning can inform the design of musical training and may offer insight into the development of phonological categories in language.

The Effects of Feature‐Label‐Order and Their Implications for Symbolic Learning

by Melody Dye

Ramscar, M., Yarlett, D., Dye, M., Denny, K., & Thorpe, K. (2010) The Effects of Feature-Label-Order and their implications for symbolic learning. Cognitive Science, 34(6), 909-957.

Symbols enable people to organize and communicate about the world. However, the ways in which symbolic knowledge is... more Symbols enable people to organize and communicate about the world. However, the ways in which symbolic knowledge is learned and then represented in the mind are poorly understood. We present a formal analysis of symbolic learning—in particular, word learning—in terms of prediction and cue competition, and we consider two possible ways in which symbols might be learned: by learning to predict a label from the features of objects and events in the world, and by learning to predict features from a label. This analysis predicts significant differences in symbolic learning depending on the sequencing of objects and labels. We report a computational simulation and two human experiments that confirm these differences, revealing the existence of Feature-Label-Ordering effects in learning. Discrimination learning is facilitated when objects predict labels, but not when labels predict objects. Our results and analysis suggest that the semantic categories people use to understand and communicate about the world can only be learned if labels are predicted from objects. We discuss the implications of this for our understanding of the nature of language and symbolic thought, and in particular, for theories of reference.