Dementia is common among long term care (LTC) residents and has many implications for their quality of life. Individuals with dementia often present with behavioural disturbances such as aggression (e.g., destructive actions toward persons, objects, or the self) that negatively affect their quality of life and may result from unmet needs (Whall et al., 2008). Egan et al. (2007), using a very small patient sample (N = 4; no control group), successfully piloted an intervention intended to influence professional caregivers’ behaviour toward residents, and thus decrease aggressive behaviours by presenting staff members with life histories of the residents. The goal of these life histories was to increase staff perceptions of patient personhood with the outcome of improving person-centered care. The current study was designed to replicate the intervention designed by Egan et al. (2007) with a larger number of participants and a control group. Within a framework of the Functional Analytic (FA) model (Fisher, Drossel, Ferguson, Cherup, & Sylvester, 2008), it was expected that changes in nurse behaviour toward the residents would lead to changes in behavioural disturbance and specifically decreases in aggressive behaviour and increases in quality of life for the residents. It was also expected that these changes in nurse behaviour would stem from increases in empathy and personhood perception. As such, perceptions of empathy and personhood would serve as mediators for the expected changes in aggressive behaviours and quality of life. Significant differences between the experimental and control groups were found following the intervention. These changes were reflected in aggressive behaviours, personhood perception, and quality of life. Mediation analyses found a significant mediated effect, with personhood perception serving as a mediator for quality of life. Additional analyses revealed a significant negative relationship between patient cognitive impairment and staff personhood perception prior to the intervention, at intervention, and at follow-up. Finally, qualitative analyses explored the attitudes staff members have toward residents and their perceptions of resident personhood. The implications of these findings are discussed.