Dual-process moral judgment beyond fast and slow

De Neys makes a compelling case that the sacrificial moral dilemmas do not elicit competing "fast and slow" processes. But are there even two processes? Or just two intuitions? There remains strong evidence, most notably from lesion studies, that sacrificial dilemmas engage distinct cognitive processes generating conflicting emotional and rational responses. The dual-process theory gets much right, but needs revision.

How Imagination and Memory Shape the Moral Mind

Interdisciplinary research has proposed a multifaceted view of human cognition and morality, establishing that inputs from multiple cognitive and affective processes guide moral decisions. However, extant work on moral cognition has largely overlooked the contributions of episodic representation. The ability to remember or imagine a specific moment in time plays a broadly influential role in cognition and behavior. Yet, existing research has only begun exploring the influence of episodic representation on moral cognition. Here, we evaluate the theoretical connections between episodic representation and moral cognition, review emerging empirical work revealing how episodic representation affects moral decision-making, and conclude by highlighting gaps in the literature and open questions. We argue that a comprehensive model of moral cognition will require including the episodic memory system, further delineating its direct influence on moral thought, and better understanding its interactions with other mental processes to fundamentally shape our sense of right and wrong.

Breakdown of utilitarian moral judgement after basolateral amygdala damage

Most of us would regard killing another person as morally wrong, but when the death of one saves multiple others, it can be morally permitted. According to a prominent computational dual-systems framework, in these life-and-death dilemmas, deontological (nonsacrificial) moral judgments stem from a model-free algorithm that emphasizes the intrinsic value of the sacrificial action, while utilitarian (sacrificial) moral judgments are derived from a model-based algorithm that emphasizes the outcome of the sacrificial action. Rodent decision-making research suggests that the model-based algorithm depends on the basolateral amygdala (BLA), but these findings have not yet been translated to human moral decision-making. Here, in five humans with selective, bilateral BLA damage, we show a breakdown of utilitarian sacrificial moral judgments, pointing at deficient model-based moral decision-making. Across an established set of moral dilemmas, healthy controls frequently sacrifice one person to save numerous others, but BLA-damaged humans withhold such sacrificial judgments even at the cost of thousands of lives. Our translational research confirms a neurocomputational hypothesis drawn from rodent decision-making research by indicating that the model-based algorithm which underlies outcome-based, utilitarian moral judgements in humans critically depends on the BLA.

The interplay of emotional and social conceptual processes during moral reasoning in frontotemporal dementia

Cooperative social behaviour in humans hinges upon our unique ability to make appropriate moral decisions in accordance with our ethical values. The complexity of the neurocognitive mechanisms underlying moral reasoning is revealed when this capacity breaks down. Patients with the behavioural variant of frontotemporal dementia (bvFTD) display striking moral transgressions in the context of atrophy to frontotemporal regions supporting affective and social conceptual processing. Developmental studies have highlighted the importance of social knowledge to moral decision making in children, yet the role of social knowledge in relation to moral reasoning impairments in neurodegeneration has largely been overlooked. Here, we sought to examine the role of affective and social conceptual processes in personal moral reasoning in bvFTD, and their relationship to the integrity and structural connectivity of frontotemporal brain regions. Personal moral reasoning across varying degrees of conflict was assessed in 26 bvFTD patients and compared with demographically matched Alzheimer's disease patients (n = 14), and healthy older adults (n = 22). Following each moral decision, we directly probed participants' subjective emotional experience as an index of their affective response, while social norm knowledge was assessed via an independent task. While groups did not differ significantly in terms of their moral decisions, bvFTD patients reported feeling 'better' about their decisions than healthy control subjects. In other words, although bvFTD patients could adjudicate between different courses of action in the moral scenarios, their affective responses to these decisions were highly irregular. This blunted emotional reaction was exclusive to the personal high-conflict condition, with 61.5% of bvFTD patients reporting feeling 'extremely good' about their decisions, and was correlated with reduced knowledge of socially acceptable behaviour. Voxel-based morphometry analyses revealed a distributed network of frontal, subcortical, and lateral temporal grey matter regions involved in the attenuated affective response to moral conflict in bvFTD. Crucially, diffusion-tensor imaging implicated the uncinate fasciculus as the pathway by which social conceptual knowledge may influence emotional reactions to personal high-conflict moral dilemmas in bvFTD. Our findings suggest that altered moral behaviour in bvFTD reflects the dynamic interplay between degraded social conceptual knowledge and blunted affective responsiveness, attributable to atrophy of, and impaired information transfer between, frontal and temporal cortices. Delineating the mechanisms of impaired morality in bvFTD provides crucial clinical information for understanding and treating this challenging symptom, which may help pave the way for targeted behavioural interventions.

Unravelling moral cognition in acquired brain injury: a scoping review

Background:

Acquired brain injury (ABI) is accompanied by impairments in social, emotional, cognitive and behavioural skills and highly prevalent in the population. Social and emotional skills are crucial for moral cognition, but the extent to which moral cognition contributes to social competence deficits in people with ABI is largely unclear.

Method:

To provide more insight on this topic, we conducted a scoping review according to the PRISMA guidelines. After screening 1269 articles that we obtained via PubMed and Scopus, we found 27 articles on moral cognition in ABI.

Results:

We encountered four important topics across these studies which include traumatic brain injury (TBI) versus non-TBI, the influence of the different approaches used to measure moral cognition in ABI, the role of age of onset and the role of location of the injury. Overall, evidence suggests that the earlier the brain damage occurred, the more this leads to impairments in moral cognitive functioning. The location of the injury furthermore seems to differentially affect the way impairments are manifested. Finally, we found that the use of different measurement approaches can heavily influence the interpretation of the impairment.

Conclusion:

We conclude that impairments in moral cognition in people with ABI are derived from a complex interplay between the age of onset, the location and the approach used to index moral cognition.

Episodic processes in moral decisions: Evidence from medial temporal lobe amnesia

Theoretical accounts of moral decision making imply distinct ways in which episodic memory processes may contribute to judgments about moral dilemmas that entail high conflict between a harmful action and a greater good resulting from such action. Yet, studies examining the status of moral judgment in amnesic patients with medial temporal lobe (MTL) lesions have yielded inconsistent results. To examine whether and how episodic processes contribute to high conflict moral decisions, amnesic patients with MTL damage and control participants were asked to judge the moral acceptability of a harmful action across two conditions that differed in the framing of the moral question. We predicted that personal (but not abstract) framing would engage episodic processes involved in mental simulation, yielding a selective impairment in MTL patients in the personal framing condition. This prediction was not confirmed as neither patients nor controls were influenced by the framing of the moral question. With the exception of a patient whose lesion extended into the amygdala bilaterally, patients were less willing than controls to endorse the utilitarian option, rejecting the harmful action despite its beneficial outcome. They also rated actions as emotionally more intense than did controls. These findings suggest that episodic processes involved in mental simulation are necessary to prospectively evaluate action-outcome contingencies.

Neuropathology of a remarkable case of memory impairment informs human memory

Kent Cochrane (K.C.) has been investigated by researchers for nearly three decades after intracranial trauma from a motorcycle accident at age 30 resulted in a striking profile of amnesia. K.C. suffered severe anterograde amnesia in both verbal and non-verbal domains which was accompanied by selective retrograde amnesia for personal events experienced prior to the time of his injury (episodic memory), with relative preservation of memory for personal and world facts (semantic memory), and of implicit memory. This pattern of spared and impaired memory extended to spatial memory for large-scale environments and beyond memory to future imagining and decision-making. Post-mortem brain findings at age 62 included moderate diffuse atrophy, left orbitofrontal contusion, left posterior cerebral artery infarct, and left anterior frontal watershed infarct. Notably, there was severe neuronal loss and gliosis of the hippocampi bilaterally. The left hippocampus was severely affected anteriorly and posteriorly, but CA2, CA4, and the dentate gyrus (DG) were focally spared. There was associated degeneration of the left fornix. The right hippocampus showed near complete destruction anteriorly, with relative preservation posteriorly, mainly of CA4 and DG. Bilateral parahippocampal gyri and left anterior thalamus also showed neuron loss and gliosis. There was no evidence of co-existing neurodegenerative phenomena on beta-amyloid, phosphorylated tau, or TDP-43 immunostaining. The extent of damage to medial temporal lobe structures is in keeping with K.C.'s profound anterograde and retrograde amnesia, with the exception of the unexpected finding of preserved CA2/CA4 and DG. K.C.'s case demonstrates that relatively clean functional dissociations are still possible following widespread brain damage, with structurally compromised brain regions unlikely to be critical to cognitive functions found to be intact. In this way, the findings presented here add to K.C.'s significant contributions to our understanding of clinical-anatomical relationships in memory.

Episodic simulation and empathy in older adults and patients with unilateral medial temporal lobe excisions

Recent work shows that vividly imagining oneself helping others in situations of need (episodic simulation) increases one's willingness to help. The mechanisms underlying this effect are unclear, though it is known that the medial temporal lobe (MTL) is critical for supporting episodic simulation in general. Therefore, individuals who have compromised MTL functioning, such as older adults and those who have undergone resection of medial temporal lobe tissue as treatment for epilepsy (mTLE patients), may not show the prosocial effects of episodic simulation. Our lab previously found that older adults and mTLE patients are impaired on a problem-solving task that requires the simulation of hypothetical scenarios. Using similar logic in the present study, we predicted that older adults and mTLE patients would show reduced effects of episodic simulation on their empathic concern for, and willingness to help, people in hypothetical situations of need, compared to young adults and age-matched healthy controls, respectively. We also predicted that the subjective vividness and the amount of context-specific detail in imagined helping events would correlate with willingness to help and empathic concern. Participants read brief stories describing individuals in situations of need, and after each story either imagined themselves helping the person or performed a filler task. We analyzed the details in participants' oral descriptions of their imagined helping events and also collected subjective ratings of vividness, willingness to help, and empathic concern. Episodic simulation significantly boosted willingness to help in all groups except for mTLE patients, and it increased empathic concern in young adults and healthy controls but not in older adults or mTLE patients. While the level of context-specific detail in participants' oral descriptions of imaged events was unrelated to willingness to help and empathic concern, the effects of episodic simulation on these measures was completely mediated by subjective vividness, though to a significantly lesser degree among mTLE patients. These results increase our understanding not only of how episodic simulation works in healthy people, but also of the social and emotional consequences of compromised MTL functioning.

Comparing and Contrasting the Cognitive Effects of Hippocampal and Ventromedial Prefrontal Cortex Damage: A Review of Human Lesion Studies

The hippocampus and ventromedial prefrontal cortex (vmPFC) are closely connected brain regions whose functions are still debated. In order to offer a fresh perspective on understanding the contributions of these two brain regions to cognition, in this review we considered cognitive tasks that usually elicit deficits in hippocampal-damaged patients (e.g., autobiographical memory retrieval), and examined the performance of vmPFC-lesioned patients on these tasks. We then took cognitive tasks where performance is typically compromised following vmPFC damage (e.g., decision making), and looked at how these are affected by hippocampal lesions. Three salient motifs emerged. First, there are surprising gaps in our knowledge about how hippocampal and vmPFC patients perform on tasks typically associated with the other group. Second, while hippocampal or vmPFC damage seems to adversely affect performance on so-called hippocampal tasks, the performance of hippocampal and vmPFC patients clearly diverges on classic vmPFC tasks. Third, although performance appears analogous on hippocampal tasks, on closer inspection, there are significant disparities between hippocampal and vmPFC patients. Based on these findings, we suggest a tentative hierarchical model to explain the functions of the hippocampus and vmPFC. We propose that the vmPFC initiates the construction of mental scenes by coordinating the curation of relevant elements from neocortical areas, which are then funneled into the hippocampus to build a scene. The vmPFC then engages in iterative re-initiation via feedback loops with neocortex and hippocampus to facilitate the flow and integration of the multiple scenes that comprise the coherent unfolding of an extended mental event.

Hippocampal Damage Increases Deontological Responses during Moral Decision Making

Complex moral decision making is associated with the ventromedial prefrontal cortex (vmPFC) in humans, and damage to this region significantly increases the frequency of utilitarian judgments. Since the vmPFC has strong anatomical and functional links with the hippocampus, here we asked how patients with selective bilateral hippocampal damage would derive moral decisions on a classic moral dilemmas paradigm. We found that the patients approved of the utilitarian options significantly less often than control participants, favoring instead deontological responses—rejecting actions that harm even one person. Thus, patients with hippocampal damage have a strikingly opposite approach to moral decision making than vmPFC-lesioned patients. Skin-conductance data collected during the task showed increased emotional arousal in the hippocampal-damaged patients and they stated that their moral decisions were based on emotional instinct. By contrast, control participants made moral decisions based on the integration of an adverse emotional response to harming others, visualization of the consequences of one's action, and the rational re-evaluation of future benefits. This integration may be disturbed in patients with either hippocampal or vmPFC damage. Hippocampal lesions decreased the ability to visualize a scenario and its future consequences, which seemed to render the adverse emotional response overwhelmingly dominant. In patients with vmPFC damage, visualization might also be reduced alongside an inability to detect the adverse emotional response, leaving only the utilitarian option open. Overall, these results provide insights into the processes involved in moral decision making and highlight the complementary roles played by two closely connected brain regions.

SIGNIFICANCE STATEMENT The ventromedial prefrontal cortex (vmPFC) is closely associated with the ability to make complex moral judgements. When this area is damaged, patients become more utilitarian (the ends justify the means) and have decreased emotional arousal during moral decision making. The vmPFC is closely connected with another brain region—the hippocampus. In this study we found that patients with selective bilateral hippocampal damage show a strikingly opposite response pattern to those with vmPFC damage when making moral judgements. They rejected harmful actions of any kind (thus their responses were deontological) and showed increased emotional arousal. These results provide new insights into the processes involved in moral decision making and highlight the complementary roles played by two closely connected brain regions.