_________________________________________________________________________Swansea University E-Theses Spontaneous and relative categorisation. Edwards, Darren J How to cite: _________________________________________________________________________ Edwards, Darren J (2010) Spontaneous and relative categorisation.. thesis, Swansea University. http://cronfa.swan.ac.uk/Record/cronfa43199 Use policy: _________________________________________________________________________ This item is brought to you by Swansea University. Any person downloading material is agreeing to abide by the terms of the repository licence: copies of full text items may be used or reproduced in any format or medium, without prior permission for personal research or study, educational or non-commercial purposes only. The copyright for any work remains with the original author unless otherwise specified. The full-text must not be sold in any format or medium without the formal permission of the copyright holder. Permission for multiple reproductions should be obtained from the original author. Authors are personally responsible for adhering to copyright and publisher restrictions when uploading content to the repository. Please link to the metadata record in the Swansea University repository, Cronfa (link given in the citation reference above.) http://www.swansea.ac.uk/library/researchsupport/ris-support/ Spontaneous and Relative Categorisation Darren J. Edwards Submitted to the University of Wales in fulfilment of the requirements for the Degree of Doctor of Philosophy Swansea University September 2010 Supervision provided by Dr. Emmanuel Pothos ProQuest Number: 10821591 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10821591 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Abstract This thesis concerns two different aspects of categorization, the first is an investigation with a novel paradigm, which relates to relative vs. absolute (supervised) categorization, and the second, an investigation of the simplicity model (Pothos & Chater, 2002). The first investigation was motivated from the relative judgment model (Stewart et al., 2005). According to this model, classification judgments in absolute identification tasks are influenced by the relative context in which they are presented. We examine the generality of this conclusion in categorization. In the present study, we tested 320 participants in 5 experiments, in which participants had to classify new items into predefined artificial categories. In three experiments, we observed a (predominantly) relative mode of classification, and in 2 experiments we observed an absolute mode of classification. These results suggest three factors which promote a relative mode of classification; when there are fewer items per group, more training groups, and the presence of a time delay. Overall, we propose that less information about the distributional properties of a category and/or weaker memory traces for the category exemplars (induced, e.g., by smaller item numbers per category, or a time delay respectively) can encourage relative judgment. For the simplicity model, we conducted three experiments, a free sort task, a learning task and a memory task. In the free sort task, we asked 169 participants to spontaneously categorize nine sets of items. A category structure was assumed to be more intuitive if a large number of participants consistently produced the same classification. Our results provide a rich empirical framework for examining the simplicity model of unsupervised categorization (Pothos & Chater, 2002). fi 2 Declaration and Statements Declaration This work has not been previously accepted in substance for any degree and is not concurrently submitted in candidature for any degree. Signed ................ Darren Edwards ............................................... D ate................ 29/9/2010.............................................. Statement 1 This thesis is the result of my own investigations, except where otherwise stated. Where correction services have been used, the extent and nature of the correction is clearly marked in a footnote(s). Other sources are acknowledged by footnotes giving explicit references. A bibliography is appended. Signed Darren Edwards ............ ................................... D ate................29/9/2010............................................... Statement 2 I hereby give consent for my thesis, if accepted, to be available for photocopying and for inter library loan, and for the title and summary to be made available to outside organizations. Signed ..................... Darren Edwards ............................................ D ate....................29/9/2010............................................. 3 Table of Contents Abstract.............................................................................................................................. 2 Acknowledgements............................................................................................................7 Research publications and conference proceedings.................................................... 8 Tables and Figures..........................................................................................................10 Chapter 1 Introduction.................................................................................................. 13 Chapter 2 The Simplicity Model in Unsupervised Categorization.........................15 2.1 Introduction.................................................................................................. 15 2.2 Exemplar Approach in Supervised Categorization vs. Unsupervised Categorization........................................................................... 17 2.3 The simplicity principle.............................................................................. 19 2.4 Measuring Simplicity.................................................................................. 23 2.5 The Simplicity Model of Unsupervised Categorization........................ 28 2.6 Other Unsupervised Models vs. the Simplicity Model...........................37 2.7 Summary....................................................................................................... 47 Chapter 3 Supervised Categorization and Absolute Judgment..............................48 3.1 An Introduction............................................................................................48 3.2 Exemplar Models..........................................................................................48 3.3 Prototype vs. Exemplar Theories of Categorisation..............................49 3.4 The Generalized Context Model of Supervised Categorization..........50 3.5 Other supervised categorization.............................................................. 52 4 3.6 Exemplar theory; the GCM and how this relates to absolute judgment ...............................................................................................................................55 3.7 Summary....................................................................................................... 57 Chapter 4 Relative Judgment in Categorization.......................................................58 4.1 An Introduction........................................................................................... 58 4.2 Absolute identification tasks...................................................................... 58 4.3 Models that account for the effects observed in absolute identification tasks..............................................................................................61 4.4 Stewarts Relative Judgement Model (RJM, 2005).................................65 4.5 Relative Judgment in Analogical Mapping............................................. 66 4.6 Relative Judgment in our experimentation..............................................69 Chapter 5 Experimental results; relative vs. absolute representation in categorization...................................................................................................................71 5.1 Introduction..................................................................................................71 5.2 Relative vs. absolute representation in supervised categorization 71 5.3 Defining relative and absolute representation........................................ 74 5.4 Experiment .................................................................................................1 77 5.5 Experiment 2.................................................................................................81 5.6 Experiment .................................................................................................3 84 5.7 Experiment .................................................................................................4 87 5.8 Experiment .................................................................................................5 88 5.9 General Discussion.....................................................................................