Sequence Position Affects Shape Categorization Open Access

Antoun, Angelle (Summer 2022)

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Language is an incredibly powerful ability that can be used to communicate a theoretically infinite range of ideas and concepts. This is possible because of the interaction of semantics, the meaning of words, and syntax, the rules that govern their organization and order. When presented with novel words, humans will use word order to determine which semantic category (noun, verb, etc.) the novel word belongs to. To determine whether this tendency to use sequence information to infer category membership exists outside of the domain of language, I examined the interaction of sequence and category using non-linguistic stimuli. I created three perceptual shape categories (rounded shapes, squared shapes, and pointed shapes), as well as a series of ambiguous intermediate shapes generated by morphing between those categories. Fifty participants first learned to categorize the shapes, and were then taught a simple sequence (rounded shape followed by squared shape, then pointed shape). When ambiguous morphs were inserted into the sequence, their position in the sequence radically shifted their categorization towards the shape whose position they occupied. This implies that the tendency to use sequence information to categorize stimuli may be a broad, generalizable ability, that occurs outside of the domain of language.

Table of Contents

Introduction 1

Artificial Grammar Learning 2

Interaction of Categories and Sequences in Language 4

Categories in Artificial Grammar and Sequence Learning Studies 6

Impact of Sequence on Categorization in Non-Linguistic Contexts 8

Methods 10

Participants 10

Stimuli 10

Procedure 14

Phase 1: Category Training 16

Phase 2: Baseline Categorization Threshold Testing 16

Phase 3: Sequence Training 16

Phase 4: Sequence Effect on Categorization Testing 18

Data Analysis 18

Results 19

Learning and attention checks 19

Effects of Sequence Position on Categorization 21

Relationship Between Performance in Sequencing Phase and Categorization 26

Individual Differences in Categorization 30

Discussion 30

References 35


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