Humans are a social species. Automatic affective responses generated by neural systems wired into our brains create a moral intuition or “gut-feeling” of wrong and right that guides our moral judgments. Humans are also an intelligent, problem solving and planning species with neural structures that enable cognitive control and the ability to reason about the costs and benefits of decisions, and moral judgments, not the least. Previous research suggests that moral intuition and moral reasoning operates on different neural networks - a dual process of moral cognition, that sometimes gives rise to an inner conflict in moral judgments. Early lesion studies found correlations between damage to the ventromedial prefrontal cortex (VMPFC) and changes in moral behaviour. This has been further established through brain imaging studies and the suggestion is that VMPFC mediates affective signals from the amygdala in moral decision making and is highly involved in generating the gut-feeling of right and wrong. However, some moral issues are complex and demand higher level processing than intuition, and the dorsolateral prefrontal cortex (DLPFC) seems to be responsible for the rational, cost-benefit reasoning during moral judgments. Further, recent research suggests that during moral judgments, the brain employ neural systems that generates the representation of value, perspective and cognitive control as well as the representation of the mental and emotional states of others. The present thesis aims to investigate prominent and up to date research on the neural correlates of necessary components in moral cognition, and to examine the function of moral intuition versus reason in relation to current complex moral issues. Moral intuition is supposedly an adaption to favour “us” before “them”, not to be concerned with large scale cooperation, which may explain why we treat many moral issues with ignorance. Understanding how the moral brain works involve understanding what sort of tasks the neural mechanisms in moral cognition evolved to handle, which may explain why some modern issues are so difficult to solve.

A phenomenon explored in the field of the cognitive neuroscience of morality is moral sensitivity, which is a collective name for a subjective experience related to the ability to detect and respond to morally relevant cues in a given social situation. This thesis will review the underlying neural mechanisms of moral sensitivity and three key components: Empathy, moral disgust and moral intuition, also called moral “gut-feeling.” Initially, the thesis provides a basic explanation of what moral sensitivity entails and the primary observations of which brain regions are often associated with moral sensitivity. Studies show that emotion and cognition seem to be essential to the experience of moral sensitivity, which will be further emphasized by reviewing the chosen key components. Research on morality and empathy suggests that the affective and the cognitive components of empathy each are essential to moral sensitivity. The second key component, moral disgust, describes how moral sensitive people react to violations to society by being motivated to keep away from social interactions with poor moral influence. Research on the third key component explains how moral sensitivity can be affected by moral intuitions, here moral “gut-feelings,” depending on the closeness and emotional salience in a given situation.

Humans express complex moral behaviour, from altruism to antisocial acts. The investigationof the neural and cognitive mechanisms underlying our moral minds is of profoundimportance for understanding these behaviours. By reviewing recent findings in cognitive andmoral neuroscience, along with other relevant areas of research, the current study aims to: (1)Investigate the neural correlates of moral intuition and moral reasoning, and see how thesetwo systems relate to moral judgement and moral behaviour. (2) Examine how the moralintuitive system and the moral reasoning system relate to one another. Neuroscientificevidence suggests that these two systems are supported by different areas in the brain. Whiletheir relationship is argued to be both sequential, integrative and competitive, evidenceindicates that the moral reasoning system primarily functions as a post hoc rationalization ofour intuitive-driven judgements and behaviours. While our moral intuitive system motivateskin altruism, both moral intuition and moral reasoning serve to uphold reciprocal altruism.