News & Views | Published:

Neurobiology

Feeling right about doing right

Nature volume 446, pages 865866 (19 April 2007) | Download Citation

Reason and emotion come into conflict in making all kinds of judgements. Results of work with brain-damaged patients constitute one line of evidence that the emotional component is not to be dismissed.

In resolving moral dilemmas, should emotion be our guide? This is a question prompted by various research avenues, including work described in the paper by Koenigs et al.1 on page 908 of this issue.

In a typical moral dilemma, we have to choose between the lesser of two evils. Causing the death of one person is bad, but causing the death of five people is even worse. So, if you are on a runaway trolley with no other options, many people say that it is better to switch to the left fork in the track, resulting in the death of one person, than to carry on along the right fork and kill five. But what if there was no fork in the track and the only way to stop the trolley killing five people was to throw a large person, who happens to be standing next to you, under the wheels? From a utilitarian point of view the dilemma is the same: should we sacrifice one person for the sake of five? But, given this version of the dilemma, most people will choose not to throw their companion to his death. Why the difference?

There is increasing evidence that there is a strong emotional component to our moral intuitions, and that this determines, to a large degree, how we make moral judgements2. Thus the benefit from sacrificing a single life for the greater good must be pitted against the emotional aversion associated with the taking of life, particularly when we are face-to-face with our victim. Measurement of brain activity while people are presented with these dilemmas confirm this intuition: the moral dilemma involving throwing our companion onto the track elicits more activity in emotion-processing regions of the brain than the standard runaway-trolley problem (see ref. 3 for a review).

The implication of these ideas is that people with impaired emotional responses will have altered moral intuitions. Koenigs and his colleagues1 have tested this hypothesis with a group of patients with damage to part of the brain called the ventral medial prefrontal cortex (VMPFC). As is typical after such damage, the autonomic nervous system in these patients showed reduced responses to emotionally charged pictures and, according to their spouses, the patients showed reduced feelings of empathy and guilt. When confronted with moral dilemmas, the patients with VMPFC lesions were more likely to choose the utilitarian option than were control participants and patients with lesions in other brain regions. This effect was particularly marked when there was high conflict between the utilitarian and the emotional component. The finding seems to be robust, as Ciaramelli et al.4 report essentially the same results in a separate VMPFC patient group.

This result engenders a paradox. On the one hand, believing that emotion is the enemy of reason, our society still goes to great lengths to prevent emotional considerations from influencing important decisions, in particular moral decisions. Intriguingly, the result reported by Koenigs and colleagues1 seems to show that damage to the VMPFC does not impair moral decision-making, but rather improves it through eliminating the effects of emotion. On the other hand, there is abundant evidence that decision-making in other spheres is severely impaired in these patients5. Indeed, it is on the basis of this latter evidence that Damasio6developed the 'somatic marker' theory, which affords a major role to emotions for making good decisions. Emotions clearly have a role in our moral intuitions, but do they improve moral decision-making, or impair it?

There is a similar conflict between reason and emotion when we make economic decisions. In the 'ultimatum game', player A is given $100 and can give a proportion of this to player B. Player B can accept the money, but, if B rejects it, neither A nor B get any money. Typically B will reject an offer of less than about $20. This behaviour does not accord with self-interest because B gets nothing rather than $20. It is also not utilitarian, as the two players, considered together, also get nothing rather than $100. Instead the behaviour is driven by the perceived unfairness of the offer. This is an emotional response because unfair offers elicit autonomic responses7 and increased activity in brain regions associated with emotions8.

Interestingly, Koenigs and Tranel9 report that, relative to control participants, their patients with VMPFC lesions when playing the ultimatum game are influenced by emotion more strongly, in that they were more likely to reject low offers. This finding, in turn, is in line with findings that activation in the VMPFC is correlated with a reduced bias by the contextual framing of a decision10. Clearly, damage to this region disrupts the integration of emotion and reasoning, but it remains to be seen why this disruption takes different forms in different circumstances. Two critical differences between the paradigms Koenigs and his colleagues employed include the nature of the stimulus, which was either representational (emotional pictures, description of a dilemma)1 or concrete (actual winning or losing a game)9, and the procedure, which required a judgement with no direct consequences to the patient, or an active engagement5. Strategic planning may be needed both to stimulate an emotional response by calling forth previous experiences, and to tone down a reactive emotional response. A role for strategic planning in the emotional response that leads to the rejection of unfair offers is supported by findings11 that disruption of function in the right prefrontal cortex reduces the effect of emotion, and biases participants towards a utilitarian response, in the ultimatum game.

Even though the precise role of VMPFC in the integration of emotion and reason remains unclear, these studies raise the perennial question as to whether emotion makes decisions better or worse. In the case of economic decisions, there is now considerable evidence that emotional rejection of unfair offers is a good strategy. Rejecting unfair offers in the ultimatum game is a form of altruistic punishment. With repeated economic encounters the use of altruistic punishment increases cooperation, resulting in greater benefits for the group12,13. By analogy, it may be possible to show that some moral decisions are improved when the emotional component is taken into account, rather than suppressed.

The challenge, then, is for decision-makers to cultivate an intelligent use of their emotional responses by integrating them with a reflective reasoning process, sensitive to the context and goals of the moral dilemmas they face. If decision-makers meet this challenge, they may be better able to decide when to rely upon their emotions, and when to regulate them. Indeed, such cultivation is already occurring in the legal system14.

References

  1. 1.

    et al. Nature 446, 908–911 (2007).

  2. 2.

    Psychol. Rev. 108, 814–834 (2001).

  3. 3.

    , , , & Nature Rev. Neurosci. 6, 799–809 (2005).

  4. 4.

    , , & Social Cogn. Affective Neurosci. (in the press).

  5. 5.

    , & Cereb. Cortex 10, 295–307 (2000).

  6. 6.

    Descartes' Error: Emotion, Reason, and the Human Brain (Putnam, New York, 1994).

  7. 7.

    , , & Exp. Brain Res. 169, 564–568 (2006).

  8. 8.

    , , , & Science 300, 1755–1758 (2003).

  9. 9.

    & J. Neurosci. 27, 951–956 (2007).

  10. 10.

    , , & Science 313, 684–687 (2006).

  11. 11.

    , , , & Science 314, 829–832 (2006).

  12. 12.

    & Nature 415, 137–140 (2002).

  13. 13.

    , & Science 312, 108–111 (2006).

  14. 14.

    Theor. Criminol. 6, 299–317 (2002).

Download references

Author information

Affiliations

  1. Deborah Talmi and Chris Frith are at the Wellcome Trust Centre for Neuroimaging at University College London, 12 Queen Square, London WC1N 3BG, UK. cfrith@fil.ion.ucl.ac.uk

    • Deborah Talmi
    •  & Chris Frith

Authors

  1. Search for Deborah Talmi in:

  2. Search for Chris Frith in:

About this article

Publication history

Published

DOI

https://doi.org/10.1038/446865a

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Newsletter Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing