Persons with behavioral variant frontotemporal dementia (bvFTD) have been shown to exhibit altered morality, manifested as atypical utilitarian tendencies towards sacrificial moral dilemmas. This takes the form of endorsing harmful actions towards single individuals, including vulnerable or relationally close individuals (e.g. children, loved ones), in order to promote the greater good for the community or society as a whole. The dual process model of moral cognition interprets such tendencies as deriving from a lack of emotional engagement, whereas moral emotion theory views them as selective impairment in prosocial sentiments. We hypothesized that both the widespread neuropsychological practice of using sacrificial moral dilemmas to evaluate moral reasoning, and these tests' overreliance on quantitative results, inadequately represent how persons with bvFTD reason and feel while responding to moral dilemmas. To evaluate this hypothesis, we applied a mixed-methods approach to identify the reasoning, motivations, and emotional experiences of bvFTD persons during their deliberation about moral scenarios.

We conducted semi-structured interviews with 14 participants: 7 persons with bvFTD & 7 older healthy controls. Transcripts were coded in Atlas 5.0 to characterize the underlying reasoning, emotions, response processes, and values that emerged when responding to a structured set of moral dilemmas. Our dilemmas measured utilitarian reasoning holistically by incorporating both sacrificial and impartial/altruistic components, as suggested by the 2-dimensional model of utilitarianism.

Unexpectedly, bvFTD persons articulated a prosocial compass when asked about their values, stating they were organizing their choices predominantly around kindness and altruism, even when they were making choices to harm loved ones or vulnerable individuals to promote the greater good. During moral deliberation, persons with bvFTD showed significantly less metacognition (bvFTD = 10%, HC = 90%) but reported more positive emotions (joy; bvFTD = 83%, HC = 17%) than negative (frustration; bvFTD = 30 %, HC = 70 %) compared to controls. Qualitatively, this observed emotional outlook was typically coupled with a more rigid, simplistic viewpoint (e.g., "I felt great, it was a no brainer"), suggesting a moral understanding lacking emotional nuance and complexity.

Our data showed that bvFTD persons' utilitarian responses to moral dilemmas did not arise from an emotionally flat or antisocial cognitive perspective, but instead were guided by positive emotionality, simplistic reasoning, and prosocial values. These findings challenge the current understanding of the reasoning processes and experiences of persons with bvFTD and highlight the importance of incorporating mixed method approaches in dementia research that take into consideration the viewpoint of the cognitively compromised individual.