June 9 , 2008
For Immediate Release

Contact: Catherine West
(202) 293-9300
cwest@psychologicalscience.org

Who Shalt Not Kill? Brain Power Leads to Level-Headedness When Faced with Moral Dilemmas

Should a sergeant sacrifice a wounded private on the battlefield in order to save the rest of his troops? Is euthanasia acceptable if it prevents needless suffering? Many of us will have to face some sort of extreme moral choice such as these at least once in our life. And we are also surrounded by less dramatic moral choices everyday: Do I buy the hybrid? Do I vote for a particular presidential candidate? Unfortunately, very little is known beyond philosophical speculation about how people understand morality and make decisions on moral issues.

Past research suggests that moral dilemmas can evoke strong emotions in people and tend to override thoughtful deliberation and reasoning. However, more recent neuroimaging research has discovered that sometimes people are capable of voluntarily suppressing these emotional reactions, allowing for decisions based on reasoning and careful deliberation of the consequences of one’s actions.

A new study appearing in the June issue of Psychological Science, a journal of the Association for Psychological Science, appears to support this neuroimaging evidence. Adam Moore of Princeton University and his colleagues Brian Clark and Michael Kane of the University of North Carolina at Greensboro tested this notion by measuring individuals’ working memory capacity -- essentially their ability to mentally juggle multiple pieces of information. The idea was that people who could best juggle information would be able to control their emotion and engage in “deliberative processing.”

The researchers then asked participants to make decisions in emotionally provocative situations. One example:

“A runaway trolley hurtles toward five unaware workmen; the only way to save them is to push a heavy man (standing nearby on a footbridge) onto the track where he will die in stopping the trolley.”

In these emotion laden scenarios, people with high working memory capacity were not only more consistent in their judgments but their answers indicated that they were considering the consequences of their choices in a way that the other participants were not.

“This suggests that emotional reactions to moral issues can drive our judgments and motivate action but can also blind us to the consequences of our decisions in some cases,” write the authors. Ultimately, people with higher working memory can be relied upon to make more consistent decisions and are able to more deeply consider consequences in these highly charged instances. 

Author Contact: Adam B. Moore amtwo@princeton.edu

# # #

Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information. For a copy of the article “Who Shalt Not Kill? Individual Differences in Working Memory Capacity, Executive Control, and Moral Judgment” and access to other Psychological Science research findings, please contact Catherine West at (202) 293-9300 or cwest@psychologicalscience.org.