Moral Judgment and Frontotemporal Networks: New Insight

Frontal lobe lesions can cause personality and social cognition impairment. Some data suggested that 2 types of patients — those with prefrontal lesions (PFL) and those with the behavioral variant of frontotemporal dementia (FTD) – experience similar distractibility, personality changes, and social inappropriateness. Patients with either diagnosis also experienced profoundly impaired moral reasoning, yet few studies have compared these patients.

A multinational team of investigators recently looked at these 2 distinct types of patients (8 with PFL and 19 with FTD) and compared their moral judgments to those of a control group (n=19). They had patients perform a task designed to disentangle the contributions of intentions and outcomes in moral judgment. Participants read 24 brief stories in which protagonists either harmed another person (negative outcome) or did no harm (neutral outcome), or the protagonists believed that they would cause harm (negative intention) or believed that they would cause no harm (neutral intention).Participants rated each situation using a 7-point Likert scale.

Regardless of diagnosis, participants with PFL or FTD judged situations in which protagonists believed that they would cause harm but did not as being more permissible than the control group (n=19). In other words, PFL and FTD patients judged attempted harm as morally permissible.

FTD patients judged harmful outcomes in the absence of harmful intentions as less permissible than the control participants.

Both diagnosed groups relied heavily on outcome rather than by the integration of intentions and outcomes.

Moral judgment may be dependent on frontotemporal networks. The authors found that PFL and FTD patients both manifested impairments in integrating intention and outcome information for moral judgment. This study appeared to be the first to directly compare a social cognition domain in 2 frontal pathologies with different etiologies. The study results highlighted the importance of comparing patients with vascular lesions and patients with neurodegenerative diseases. This study was published in the November issue of JAMA Neurology.