In moral psychology, moral identity has been viewed as a central explanatory construct in moral development linking morality and action. However, less is known about its development across the lifespan. The present dissertation aimed to address the limitations of previous research by using the personological approach to better understand how the multifaceted construct of moral identity develops from the understudied period of middle childhood to adolescence. The dissertation is separated into three chapters that can be considered as three research topics framed within one study tapping into the different layers of moral identity (see Krettenauer & Hertz, 2015). All chapters were derived from the same sample of 190 participants (101 females, M=13.00 years, SD=2.58) from three age groups of approximately equal size: middle childhood (Grades 4-5; n=65), early adolescence (Grades 7-8; n=68), and mid-adolescence (Grades 10-11; n=57).
The first chapter examined the self-importance and context-specificity of moral values (trait layer of moral identity). Age-related patterns were found on this layer of moral identity and parental support was a positive predictor of moral identity. The second chapter focused on moral identity motivation (characteristic adaptations layer of moral identity) and as expected, moral identity motivation varied by both age and social context, and was also predictive of moral behaviour. The third chapter focused on narrative accounts of past morally relevant behaviour (narrative layer of moral identity). Results revealed meaningful asymmetries in participants’ experiences and interpretations of past (im)moral action that varied by age and context.
Overall, the present dissertation demonstrated the utility of the personological approach to moral identity development with each layer of moral identity manifesting differentially throughout the lifespan. Importantly, the dissertation provided evidence that moral identity development is context-dependent, begins to emerge in middle childhood perhaps as a social moral identity, and progresses to be more autonomous with age
