Investigating opposing aftereffects in 8-year-olds and adults

Previous studies have shown that adults and 8-year-olds process faces using norm-based coding and that prolonged exposure to one kind of facial distortion (e.g., compressed features) temporarily shifts the prototype, a process called adaptation, making similarly distorted faces appear more attractive (Anzures et aI., 2009; Valentine, 1999; Webster & MacLin, 1999). Aftereffects provide evidence that our prototype is continually updated by experience. When adults are adapted to two face categories (e.g., Caucasian and Chinese; male and female) distorted in opposing directions (e.g., expanded vs. compressed), their attractiveness ratings shift in opposite directions (Bestelmeyer et aI., 2008; Jaquet et aI., 2007), indicating that adults have dissociable prototypes for some face categories. I created a novel meth04 to investigate whether children show opposing aftereffects. Children and adults were adapted to Caucasian and Chinese faces distorted in opposite directions in the context of a computerized storybook. When testing adults to validate my method, I discovered that opposing aftereffects are contingent on how participants categorize faces and that this categorization is dependent on the context in which adapting stimuli are presented. Opposing aftereffects for Caucasian and Chinese faces were evident when the salience of race was exaggerated by presenting faces in the context of racially segregated birthday parties; expanded faces selected as most normal more often for the race of face that was expanded during adaptation than for the race of face that was compressed. However, opposing aftereffects were not evident when members of the two groups were presented engaging in cooperative social interactions at a racially integrated birthday party. Using the storybook that emphasized face race I 11 provide the first evidence that 8-year-olds demonstrate opposing aftereffects for two face categories defined by race, both when judging face normality and when rating attractiveness.

Challenging Weight Loss: The Effectiveness of a 12 Week Weight Loss Challenge on Weight Loss, Physical Activity and Motivation

The objective of this study was to examine the effectiveness of a 12 week weight loss intervention in a commercial fitness centre on body mass index (BMI), moderate to vigorous physical activity (MVPA) and behavioural regulations consistent with Organismic Integration Theory (OIT, Deci & Ryan, 2002). The intervention group received weekly coaching sessions and bi-weekly seminars designed to increase MVPA and improve dietary intake. The results of the mixed model analyses of variance showed a significant within-subjects main effect for BMI (F = 3.57, p = .04). Changes in MVPA were not observed over time or between conditions. Changes in behavioural regulations congruent with OIT (Deci & Ryan, 2002) favoured the intervention condition. Study results indicate that 12 week weight loss challenges in commercial fitness centres may be effective to support the internalization process of exercise behavioural regulations but ineffective at producing sustainable weight loss or behavioural changes.

The Search for Scholarly Teaching in Elementary Education

Elementary teachers are expected to prepare students to work efficiently with others, solve complex problems and self-regulate their own learning. Considering the importance of a solid educational foundation in the early years, students would benefit if elementary teachers engaged in scholarly teaching. The purpose of this study was to investigate Boyer’s (1990) four dimensions of scholarship, application, integration, teaching and discovery, to better understand if there is scholarly teaching in elementary education. Four professional teaching documents were analyzed using a hermeneutic orientation. A deductive analysis suggests that we do have scholarly teaching in elementary education, with strong evidence that elementary teachers are scholars of application and integration. An inductive analysis of latent and manifest content suggests that underlying humanistic values run deeply through elementary education driving current curricular, instructional and pedagogical practices.

The Role of Experience in the Organization and Refinement of Face Space

Adults code faces in reference to category-specific norms that represent the different face categories encountered in the environment (e.g., race, age). Reliance on such norm-based coding appears to aid recognition, but few studies have examined the development of separable prototypes and the way in which experience influences the refinement of the coding dimensions associated with different face categories. The present dissertation was thus designed to investigate the organization and refinement of face space and the role of experience in shaping sensitivity to its underlying dimensions. In Study 1, I demonstrated that face space is organized with regard to norms that reflect face categories that are both visually and socially distinct. These results provide an indication of the types of category-specific prototypes that can conceivably exist in face space. Study 2 was designed to investigate whether children rely on category-specific prototypes and the extent to which experience facilitates the development of separable norms. I demonstrated that unlike adults and older children, 5-year-olds rely on a relatively undifferentiated face space, even for categories with which they receive ample experience. These results suggest that the dimensions of face space undergo significant refinement throughout childhood; 5 years of experience with a face category is not sufficient to facilitate the development of separable norms. In Studies 3 through 5, I examined how early and continuous exposure to young adult faces may optimize the face processing system for the dimensions of young relative to older adult faces. In Study 3, I found evidence for a young adult bias in attentional allocation among young and older adults. However, whereas young adults showed an own-age recognition advantage, older adults exhibited comparable recognition for young and older faces. These results suggest that despite the significant experience that older adults have with older faces, the early and continuous exposure they received with young faces continues to influence their recognition, perhaps because face space is optimized for young faces. In Studies 4 and 5, I examined whether sensitivity to deviations from the norm is superior for young relative to older adult faces. I used normality/attractiveness judgments as a measure of this sensitivity; to examine whether biases were specific to norm-based coding, I asked participants to discriminate between the same faces. Both young and older adults were more accurate when tested with young relative to older faces—but only when judging normality. Like adults, 3- and 7-year-olds were more accurate in judging the attractiveness of young faces; however, unlike adults, this bias extended to the discrimination task. Thus by 3 years of age children are more sensitive to differences among young relative to older faces, suggesting that young children's perceptual system is more finely tuned for young than older adult faces. Collectively, the results of this dissertation help elucidate the development of category-specific norms and clarify the role of experience in shaping sensitivity to the dimensions of face space.