Neurocomputational mechanisms engaged in moral choices and moral learning

Abstract

The neural circuitry involved in moral decisions has been studied since the early days of cognitive neuroscience, mainly using moral dilemma. However, the neurocomputational mechanisms describing how the human brain makes moral decisions and learns in various moral contexts are only starting to be established. Here we review recent results from an emerging field using model-based fMRI, which describes moral choices at a mechanistic level. These findings unify the field of moral decision making, extend a conceptual framework previously developed for value-based decision making and characterize how moral processes are computed in the brain. Moral dilemma can be modeled as value-based decisions that weigh self-interests against moral costs/harm to others and different types of prediction errors can be distinguished in different aspects of moral learning. These key computational signals help to describe moral choices and moral learning at an algorithmic level and to reveal how these cognitive operations are implemented in the brain. This researches provide a foundation to account for the neurocomputational mechanisms underlying moral decision making.

Moral learning and decision-making across the lifespan

“…A recent approach, mostly developed in adolescents and adults, has been to combine economic games (DG, UG, trust game), or new moral tasks (Rutledge et al 2016;van Baar et al 2019), with computational modelling and model-based fMRI to study the neurocomputational mechanisms underlying moral emotions. Using this approach, empathy, guilt and its anticipation, envy and other moral emotions, have been defined using computational models (Fehr & Schmidt 1999;Qu et al 2022).…”

“…When making choices that weigh moral against monetary cost/benefit, areas of the brain involved in valuation are engaged (Qu et al 2022). In one study, a trade-off between moral cost and self-monetary benefit engaged the lateral PFC and the anterior insula (Qu et al 2019).…”

“…The question of what makes humans moral has been of interest to philosophers, psychologists, economists, and sociologists for centuries. At a basic level, we can define morality as the set of norms and values subscribed to by a social group to guide its actions in terms of good and bad (Crockett 2013;DeScioli & Kurzban 2009;Qu et al 2022;Tomasello & Vaish 2013). A key question is how and when such morality develops, and does it differ across our lifespan?…”

“…A key question is how and when such morality develops, and does it differ across our lifespan? In addition, research has begun to focus on using mathematical computational models of value-based learning and decision-making to link cognition, behaviour and neural activity (Crockett 2013;Qu et al 2022). How can we use this framework to understand the development of learning and decision-making in a moral context, and are some of the foundational components of these models apparent from infancy to old age?…”

Moral conviction interacts with metacognitive ability in modulating neural activity during sociopolitical decision-making

“…Functional neuroimaging studies have also consistently identified a set of interconnected regions underlying moral decision-making. This circuit includes the ventromedial prefrontal cortex (vmPFC), the ventral striatum (VS), the lPFC, and aINS (Qu et al, 2022;Yoder & Decety, 2018). Consistent with the common-currency hypothesis, some studies have demonstrated that the valuation system, including the vmPFC and VS, tracks the subjective value of voluntary donations and the appropriateness ratings of sociopolitical violence (Clithero et al, 2011;Hare et al, 2010;Workman et al, 2020).…”