Adults perceive basic emotional facial expressions as discrete categories using
categorical perception. Within categorical perception, discrimination of facial emotional expressions is better for between category faces than within category faces. In this thesis, I examined the developmental trajectory of categorical perception in early childhood. I also examined the relationship between sensitivity to physical differences in facial emotional expressions and the use of emotion labels in toddlers. In Chapter 2, I found that infants before 12-months failed to discriminate between category faces along a happy-sad continuum. In contrast, evidence suggest that 9- and 12-month old infants categorically perceived faces along a happy-angry continuum. These findings suggest that categorical perception may not develop concurrently for all emotions. In Chapter 3, I found that toddlers by 26-months of age categorically perceived faces along a happy-sad continuum. These results highlight the long developmental trajectory of categorical perception of facial emotional expressions across early childhood. In Chapter 4, I found a relationship between perceptual sensitivity to physical differences between happy and sad faces, and the emotion vocabulary size in 26-month-olds. This relationship suggests that learning about emotions may utilize information from multiple domains, and that learning in one domain may influence the development of another. The perception of facial emotional expressions is an essential component of early social emotional development. Categorical perception is a mechanism that aids in organizing complex social information from faces into actionable categories. The research in this thesis advances our understanding of early social perceptual development and the process that allow us to successfully navigate in the social world. / Dissertation / Doctor of Philosophy (PhD) / Humans are experts at reading faces. Specifically, they are capable of interpreting
complex social information from faces, including emotions, and using this information to navigate social situations. In order to organize facial emotional information, humans use a mechanism called categorical perception to quickly and efficiently sort facial emotional information into discrete categories. Inferences can be made about members within a category, which aids in the prediction and production appropriate behaviours. However, there has been limited research into the development of categorical perception in early childhood. The key goal of this thesis was to develop infant and toddler appropriate methodologies that capture the development categorical perception. In this thesis, I found that categorical perception does not develop uniformly across all ages and between different emotions. Results suggest that perceptual sensitivity to differences in facial emotional expression may be influenced by the use of emotion labels, or vice versa.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/20665 |
| Date | January 2016 |
| Creators | Lee, Vivian |
| Contributors | Rutherford, M.D., Psychology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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