An fMRI Investigation of Emotional Engagement in Moral Judgement

Joshua D. Greene, R. Brian Sommerville, Leigh E. Nystrom, John M. Darley, Jonathan D. Cohen

Ching-Ju (C.J) Tseng & Noralie Krepel04/14/2014

Abstract

Reason and emotion are likely to play important roles in moral judgement, however, little is known about their neural correlates, the nature of their interaction and the factors can modulate their influences.

“We argue that moral dilemmas vary systematically in the extent to which they engage emotional processing and that these variations in emotional engagement influence moral judgement” (Greene et al., 2001)

Introduction

Dilemma: the trolley dilemma & the footbridge dilemma

“There is no set of consistent, readily accessible moral principles that captures people’s intuitions concerning what behavior is or is not appropriate in these and similar cases” (Greene et al., 2001)

So then, what is it that makes people conclude that in the trolley dilemma it is acceptable to hit the switch, but in the footbridge dilemma it is not acceptable to push the stranger off the bridge?

“We maintain that, from a psychological point of view, the crucial difference between the trolley dilemma and the foodbridge dilemma lies in the latter’s tendency to engage people’s emotions in a way that the former does not” (Greene et al., 2001)

Hypothesis: “Some moral dilemmas (those relevantly similar to the footbridge dilemma) engage emotional processing to a greater extent than others (those relevantly similar to the trolley dilemma), and these differences in emotional engagement affect people’s judgement” (Greene et al., 2001)

Predictions

1. During contemplation of dilemmas such as the footbridge dilemma, brain areas associated with emotion would be more active as compared to contemplation of dilemmas such as the trolley dilemma.

2. “A pattern of behavioral interference similar to that observed in cognitive tasks in which automatic processes influence responses” would occur (Greene et al., 2001).

(3. Individuals that would find pushing the stranger off the bridge in the footbridge dilemma acceptable exhibit a longer reaction time as a result of countervailing their emotional response).

Methods

60 practical dilemmas

“moral”

“non-moral”

“non-moral”: taking the train or the bus

“moral”

moral-personal: up close, personal, more emotional (?), footbridge

moral-impersonal: less personal, less emotional (?), trolley

Judge the actions by saying “appropriate” or “inappropriate”

Two experiments: in each experiment, nine participants responded to the 60 dilemmas while undergoing brain scanning using fMRI

Results Experiment 1Moral-personal Moral-impersonal*

Medial portions of Brodmann’s Areas (BA) BA 9 and 10 (medial frontal gyrus)BA 31 (posterior cingulate gyrus)BA 39 (angular gyrus, bilateral)Associated with emotion

Working memoryBA 46 (middle frontal gyrus, right)BA 7/40 (parietal lobe, bilateral)

*Areas associated with working memory have been found to become less active during emotional processing. In this study, both BA 46 and BA 7/40 were found to become less active during the moral-personal condition as compared to the moral-impersonal and non-moral condition. However, they do not say to have found that these areas were associated with moral-impersonal or non-moral judgements. They simply were not associated with moral-personal judgements.

Experiment 2Trolley Problem (Moral-impersonal)

Footbridge problem (moral-personal)

Non-moral decisions

• Purpose: to replicate the results of experiment 1 and provide data concerning reaction time

• Results:Almost identical to experiment 1, except: No difference in Brodmann’s Areas 9/10 between moral-impersonal and non-moral. No difference for BA 46.

• Reaction timeAccording to the predicting theory,In the moral-personal condition, responses of “appropriate” is “emotionally incongruent”, whereas responses of “inappropriate” is “emotionally congruent”.

• ConclusionThe moral-personal condition had an effect significantly different from the moral-impersonal & non-moral condition.Brain areas associated with emotion showed increased relative activation in the moral-personal condition.Moral-impersonal judgments resembles more to non-moral judgments than to moral-personal judgments.

• DiscussionPsychological puzzle: How do people “manage to conclude” that it is acceptable to sacrifice one for the sake of five in the trolley dilemma but not in the footbridge dilemma?

Answer: There are systematic variations in the engagement of emotion in moral judgment. Pattern of neural activity in emotion-related brain areas differs between the trolley dilemma and the footbridge dilemma.

• Philosophical puzzle: Why is it acceptable to sacrifice one person to save five others in the trolley dilemma but not in the footbridge dilemma?

Answer:

• Philosophical puzzle: Why is it acceptable to sacrifice one person to save five others in the trolley dilemma but not in the footbridge dilemma?

Answer: