The purpose of this mixed method study was to investigate the relationship between the narrative construction of self-identity and positive change in antisocial behaviour in pregnant and parenting young women. It focused on two related aspects of identity development: (1) individuals’ conceptualizations of their personally salient self-values; and (2) “self-action coherence”: the process of constructing self-narratives that establish coherence between one’s personally salient self-values and behaviour. This study also included a qualitative exploration of how becoming a mother in adolescence and early adulthood is related to processes of identity development and behavioural change. Participants were 27 pregnant and parenting young women (ages 16 to 22) recruited from youth-serving agencies in Toronto, Ontario. Participants completed a questionnaire on history of engagement in antisocial behaviour and a semi-structured interview that explored self-identity and critical life experiences. Analyses of participant interviews suggest that positive behavioural change in pregnant and parenting young women is related to active engagement in self-reflection motivated by a convergence of meaning gleaned from a variety of life experiences, including the transition to motherhood. Quantitative findings suggest that: (1) an orientation to relational values is related to lower reported recent engagement in antisocial behaviour; (2) self-action coherence develops across adolescence and early adulthood; and (3) self-action coherence is related to reported positive behavioural change. Overall, the findings suggest that an orientation to relationships is important for establishing positive patterns of behaviour and that positive behavioural change in pregnant and parenting young women involves a process of constructing personally salient self-values and establishing behaviours that cohere with these values. The findings have theoretical implications relating to identity development in adolescence and early adulthood and its relations to behavioural functioning. The findings also have implications for applied work with pregnant and parenting young women with histories of antisocial behaviour.

Social interactions in early life influence the organization of neural and behavioural systems of developing mammalian young. Deprivation of social interactions with the primary caregiver and other immediate conspecifics (early social deprivation) has lasting consequences on behavioural functioning in later life. The purpose of this thesis was to investigate how early social deprivation affects the motivational aspects of behaviour in the context of appetitive stimuli. Rats were reared in complete isolation from the mother and litter using the method of artificial rearing (AR). Control rats were maternally reared (MR). In adulthood, rats were tested in a series of behavioural paradigms designed to assess the motivational impact of primary food reward and reward-related cues on food-seeking behaviour. AR increased the behavioural responsiveness of rats to the motivational impact of reward-related cues, but not to primary rewards themselves. Specifically, there were no significant effects of AR on food consumption or goal-directed instrumental responding for food. However, AR enhanced instrumental responding triggered by a previously conditioned reward cue. AR also increased the expression of approach behaviour towards a localizable conditioned reward cue and instrumental responding when the same cue was used as a reinforcer. An assessment of the mediating factors during development revealed that the lack of tactile stimulation normally received from the mother, but not sustained exposure to the stress hormone corticosterone, contributed to the long-term effects of AR. These findings represent a potential link between early-life social adversity and vulnerability to the development of problems with behavioural inhibition and attention in the presence of appetitive environmental cues.

Children with co-occurring internalizing and externalizing problems (MIXED children) represent a distinct aggressive subtype with negative outcomes; understanding what works for them in treatment is imperative. The success of MIXED children in some family-based programs for aggression may be attributable to collateral reductions in internalizing symptoms. The current study examined whether reductions in internalizing behaviour in MIXED children were due to reductions in maternal depression and parent-child co-rumination. Co-rumination, a dyadic interaction related to internalizing symptoms, is defined as excessively discussing problems and dwelling on negative feelings. We investigated 154 MIXED children and 49 pure externalizers who underwent Parent Management Training/Cognitive Behavioural Therapy. Mother-child co-rumination was assessed using videotaped observations of problem discussions gathered at pre-treatment, post-treatment and follow-up. We hypothesized that, at pre-treatment, mother-child co-rumination would mediate the relation between maternal depression and child internalizing problems. During treatment, we expected that co-rumination and maternal depression would predict reductions in child symptoms. Finally, we hypothesized that reductions in co-rumination would mediate the association between improvements in maternal depression and improvements in child internalizing which would, in turn, impact externalizing outcomes. Results did not support our pre-treatment and during treatment hypotheses about the role of co-rumination as a mediator. At pre-treatment, maternal depression was associated with child internalizing problems and co-rumination; co-rumination was not associated with internalizing when controlling for maternal depression. Reductions in maternal depression were associated with improvements in child internalizing and, marginally, with child externalizing, thus partially supporting our hypotheses. We also found that reductions in co-rumination impacted child externalizing, but not internalizing behaviour, again partially supporting our hypotheses regarding co-rumination changes and child symptom changes. Finally, results demonstrated that internalizing improvements affected externalizing outcomes, partially supporting our treatment-related hypothesis. Findings have implications for understanding the development and treatment of problems in MIXED children.

Prior research has demonstrated that bilinguals outperform monolinguals on tasks requiring set shifting – that is, the ability to shift between different ways of thinking about an object or situation. For example, bilingual children have been shown to outperform monolingual controls on false-belief tasks and on the Dimensional Change Card Sort (DCCS) task. The present study aimed (a) to examine whether the bilingual advantage in false-belief and DCCS tasks can be replicated when accounting for languages/cultures and socio-economic status and (b) to determine whether inhibitory control, metarepresentation, and/or working memory underlie the advantage, if any exists. Three language groups (24 English monolingual, 24 French monolingual, and 24 English-French bilingual preschoolers) were tested on the following tasks: false-belief (FB) tasks, the DCCS task, an inhibitory control task (Stroop task), a metarepresentation task (Identity Statements task), a working memory task (Backward Word Span), and receptive language proficiency tests. Socio-economic status was measured through a parental questionnaire containing questions about parental income and education. Results showed that the three language groups were equivalent on socio-economic measures. Despite having significantly lower language proficiency scores, bilinguals’ raw scores on FB and DCCS tasks did not differ from monolinguals’ raw scores. After statistically controlling for language proficiency and age, bilinguals had significantly higher FB scores, but did not differ from monolinguals on DCCS scores. Analyses were then performed to determine whether inhibitory control, metarepresentation, and/or working memory help bilinguals “do more” in FB “with less” language proficiency. Working memory emerged as the likely candidate that compensates for the negative effect of bilingual children’s low language proficiency on FB performance because, after controlling for age and language proficiency, it was the only cognitive ability that fulfilled both criteria: (a) its measure correlated significantly with FB and (b) there was a bilingual advantage over both monolingual groups in the measure. A mediation analysis confirmed that the working memory measure significantly mediates the relation between bilingual status and FB while controlling for age and language proficiency. Both components of the working memory measure – that is, understanding of task instructions and maintenance/manipulation capacity – mediate this relation.

This thesis investigates development and transfer of oral reading fluency among early French immersion students. Using a longitudinal design, students were assessed on phonological awareness, rapid naming, word-level fluency and text-level fluency in English and in French in Grade 2 and Grade 3. In three related studies, this thesis examines transfer both within levels of fluency individually (word-level and text-level) and between levels of fluency (from word-level to text-level). The results indicated that word-level fluency significantly improved over the one-year period in both English and in French. Language status comparing English-as-first-language students (EL1) and English-language-learners (ELLs) did not influence fluency performance in either language. Further, results showed bidirectional transfer of fluency at the word-level and the text-level independently, and unidirectional transfer from word to text fluency from French to English only. These findings provide evidence supporting cross-language transfer of oral reading fluency both within and between levels of the construct.

The present mixed-methods study examined adolescents’ social perspective taking in contexts of social justice as demonstrated by their awareness and interpretations of hypothetical peer interactions depicting racism and sexism. Fifty adolescents in Grades 9 and 12 participated in a semi-structured interview in which they were presented with two scenarios, involving adolescents in conflicts portraying racism and sexism. They were asked a series of questions designed to elicit their awareness and understanding of social group differences. Qualitative analyses revealed three categories of adolescents’ responses, reflecting distinct interpretations of social group differences. On average, adolescents assumed a perspective that was naïve to the disparities existing between vulnerable and less vulnerable social groups. Furthermore, it was shown that older adolescents had significantly more sophisticated social justice understandings than younger adolescents. These findings highlight the need to educate adolescents about issues of social justice and facilitate an appreciation of social group differences.

This thesis investigates development and transfer of oral reading fluency among early French immersion students. Using a longitudinal design, students were assessed on phonological awareness, rapid naming, word-level fluency and text-level fluency in English and in French in Grade 2 and Grade 3. In three related studies, this thesis examines transfer both within levels of fluency individually (word-level and text-level) and between levels of fluency (from word-level to text-level). The results indicated that word-level fluency significantly improved over the one-year period in both English and in French. Language status comparing English-as-first-language students (EL1) and English-language-learners (ELLs) did not influence fluency performance in either language. Further, results showed bidirectional transfer of fluency at the word-level and the text-level independently, and unidirectional transfer from word to text fluency from French to English only. These findings provide evidence supporting cross-language transfer of oral reading fluency both within and between levels of the construct.

The gender normative hypothesis of relational aggression and psychopathology states that relational aggression is more detrimental to boys than it is to girls because relational aggression is more normative in girls. In the present study, this hypothesis was tested in a large sample of 6-to-18-year-old children and this hypothesis was also extended to the domain of age norms. Specifically, it was tested whether relational aggression would also be most detrimental outside of the age in which it is most normative. The results showed some evidence supporting the gender normative hypothesis. Specifically, it was found that relationally aggressive boys suffered more internalizing and externalizing problems than non-relationally aggressive boys did. Relationally aggressive girls, however, suffered only more externalizing problems than non-relationally aggressive girls did. Results did not support the age normative hypothesis. Implications of these findings and future directions are discussed.

Adults and young children have been found to distinguish between moral and social conventional acts, which are considered to entail distinct domains of reasoning (e.g., Turiel 1983). Recently, research has begun to examine the neural basis of moral judgments (e.g., Greene et al., 2001), but these studies did not examine the development of neurocognitive processing of judgments in these two domains. The present study focused on detection of cognitive conflict as a neurocognitive process that distinguished judgments of moral and conventional violations. The N2 component of the ERP was examined in order to determine whether the two types of violation are associated with different neurophysiological correlates and whether they change with development. In a series of five experiments, reaction times and ERPs were recorded from 12- to 14-year-old children and undergraduates who read scenarios that had one of three possible endings: (1) moral violations, (2) conventional violations, (3) no violation (neutral acts). Participants judged whether the act was acceptable or unacceptable when a rule was assumed or removed. Results indicate that reaction times were faster for moral than conventional violations when a rule was assumed for both undergraduates and children, as well as when a rule was removed for children but not for undergraduates. ERP data indicated that adults’, but not children’s, N2 amplitudes were larger (i.e., more negative) for conventional than iii moral violations when a rule was assumed. Furthermore, source analysis indicated generators for the N2 in dorsomedial and ventromedial prefrontal cortices. The results suggest that judgments of conventional violations involve increased conflict detection as compared to moral violations, and these two domains are processed differently across development. The findings were explained by the idea that judgments of conventional violations are more explicitly dependant on rules, whereas judgments of moral violations are based more directly on the intrinsic negative consequences of the act.

Introduction. Executive function refers to the top-down neurocognitive processes involved in flexible, goal-oriented behavior. A number of studies have shown positive effects of EF training. The overall aim of these studies was to explore the neurocognitive processes that support the development of EF by understanding how EF training works and what the active ingredients are. Particular interest was in isolating the role of reflection in EF training to understand its top-down affect on ACC-mediated conflict detection. Method. In Exp. 1 the neural markers of EF were explored by comparing ERPs of preschoolers who passed the DCCS and preschoolers who failed. Exp. 2 represents an attempt to replicate the key findings of Kloo & Perner, (2003, Exp. 2) that reflection training improves preschoolers’ performance on the DCCS and demonstrates far transfer. A shortened version of the training protocol was also tested (Exp. 3). In Exp. 4, the neural correlates of reflection training in preschoolers were explored by examining changes in the neural marker of EF found in Exp. 1. Results. In Exp. 1, the N2 amplitude was smaller (less negative) for children who passed the DCCS and were able to efficiently resolve the conflict in the stimuli than for children who failed and were unable to resolve the conflict. Exp. 2 replicated the findings of Kloo & Perner, (2003, Exp. 2) even using a brief (15 min) intervention targeting reflection (Exp. 3). In Exp. 4, one brief session of reflection training made children who initially failed the DCCS look like children who initially passed at both the behavioral and neural level (reduced N2 amplitude). Conclusion. Results suggest that reflective processing facilitates the development of EF in young children by teaching them to notice conflict, reflect on it, and formulate rules for resolving it, resulting in the down-regulation of ACC-mediated conflict detection.