Immoral behaviour following brain damage: A review

Abstract

Despite the apparent sociability of human kind, immoral behaviour is ever present in society. The term 'immoral behaviour' represents a complex array of conduct, ranging from insensitivity to topics of conversation through to violent assault and murder. To better understand the neuroscience of immoral behaviour, this review investigates two clinical populations that commonly present with changes in moral behaviour - behavioural-variant frontotemporal dementia and acquired brain injuries. Based on evidence from these groups, it is argued that rather than a single underlying cause, immoral behaviour can result from three distinct types of cognitive failure: (1) problems understanding others; (2) difficulties controlling behaviour; or (3) deficits in the capacity to make appropriate emotional contributions. Each of these failures is associated with damage to different brain regions. A more nuanced approach to the neuroscience of immoral behaviour has important implications for our understanding of immoral behaviour in a wide range of clinical groups, as well as human society more broadly.

The interplay of emotional and social conceptual processes during moral reasoning in frontotemporal dementia – a role for the uncinate fasciculus

“…While we did not have the statistical power in the current study, it will also be important to explore whether, and how, these processes vary across different types of personal high-conflict moral dilemmas (Rosas & Koenigs, 2014). Finally, despite not forming the focus of our investigations, significant potential scope exists for delineating additional neurocognitive processes involved in personal moral decision making, such as episodic memory (see Craver et al, 2016;McCormick et al, 2016 and Supplementary Results), cognitive control (Greene, Nystrom, Engell, Darley, & Cohen, 2004), and theory of mind (Roberts, Henry, & Molenberghs, 2019;. By unpacking the mechanisms of altered morality in bvFTD, we provide crucial clinical information for understanding and treating this challenging symptom, in turn paving the way for targeted behavioural interventions.…”

Association of Neuropathologically Confirmed Frontotemporal Dementia and Alzheimer Disease With Criminal and Socially Inappropriate Behavior in a Swedish Cohort

“…This finding is not surprising because patients with FTD have often experienced damage to their frontal lobes, where impulse control (among other functions) is located. 10 …”

“…In the context of neurodegenerative diseases, deviant behaviors are often associated with damage to the frontotemporal areas. 8 , 9 , 10 Criminal and socially inappropriate behaviors constitute a significant burden to society, patients’ relatives, and patients themselves; they may result in substantial financial loss and caregiver distress. 11 , 12 , 13 , 14 …”

Effects of brain lesion on moral behavior and relevant ethical dilemma

“…不道德行为指违背人们广 泛认可的道德规范且不被他人接受的行为 [12,13] . 有研 究指出, 不道德表现为一系列复杂行为, 小到日常谈话 中因麻木迟钝造成的人际冒犯, 大到暴力侵犯与谋 杀 [14] ; 也有研究认为, 不道德的主要后果是暴力行为, 但这种说法尚存争议 [15] . 对道德情境中的消极情绪敏感.…”

“…对道德情境中的消极情绪敏感. Roberts等人 [14] 基于脑 损伤的综述性研究认为, 可能造成不道德行为的脑区 损伤包括杏仁核、前扣带回、额下回、眶额叶、后侧 颞上沟、颞顶连接处、腹内侧前额叶、前脑岛等的损 伤. Christen和Müller [8] 认为, 直接参与不道德行为的皮 层结构主要有右侧眶额叶和右侧腹内侧前额叶, 皮下 结构主要有杏仁核、海马和基底核. 关于特定不道德 行为有研究者认为, 与暴力行为有关的脑区损伤包括 额叶、左侧边缘系统、小脑扁桃体、脑岛等的损伤以 及胎儿期药物滥用导致的全脑损伤、问题养育环境导 致的注意力失调有关的脑区损伤等 [18] .…”