When we make these moral judgments, to what extent are people driven by their ability to reason about the consequences of their actions, or are they influenced by their emotions? For the past 25 years, researchers have become increasingly interested in the role that emotions play in complex judgments like moral decisions. For example, Antonio Damasio reviews evidence for the role of emotion in cognitive processing in his book Descartes’ Error.

Once we accept that emotion plays some role in complex decisions, it is important to figure out which emotions are influencing different kinds of choices. This issue was explored in an interesting paper by Adam Perkins and several colleagues in the August, 2013 issue of the Journal of Experimental Psychology: General.

These researchers were interested in moral . In particular, many psychologists have looked at how participants respond in vignettes in which their actions could potentially cause harm to others. Quite a bit of research demonstrates that people don’t like to cause harm to others, but that they are particularly averse to causing harm when they have to perform an action that causes direct harm to a person.

For example, imagine a situation in which you are working in a hospital as a late-night guard. An accident happens next door, and deadly fumes are released that get into the hospital’s ventilation system. These fumes will kill three patients, but if you flip a switch, you can redirect the fumes to another area of the hospital that will kill only one patient. In cases like this, although there is clearly a dilemma, people often elect to flip the switch.

As a second example, imagine that you are taking a cruise, when the ship catches fire and you have to get on a lifeboat. All of the lifeboats have too many people on them, and are in danger of sinking. In your boat, there is an injured person who is going to die before you are rescued. If you throw that person overboard, the boat will not sink and everyone else will be saved. In this situation, people are reluctant to throw the person overboard, because this action would directly cause the death of the person.

The researchers suggest that the emotion of is a key factor that keeps people from stating that they would be willing to cause someone’s death directly in these vignettes. To test this possibility, participants were given vignettes like these as well as control stories in which people had to make decisions with no moral dimension like which of two raffle tickets to buy based on the prize available.

To test the role of anxiety in these decisions, 40 participants were run in three sessions. In two of those sessions, participants were given a low or a moderate dose of the anti-anxiety drug lorazepam. In the other session, participants received a .

The drug had no reliable effect on people’s decisions for choices that had no moral element or for people’s choices when their actions would cause a person’s death indirectly. However, participants were most likely to elect to directly cause a person’s death in these dilemmas on the highest dose of lorazepam, least likely to cause the death in the placebo condition with the low dose condition in-between.

These results have to be taken with some caution. The effects are rather small. Participants made decisions in six decisions of each type in each session. In the placebo condition, participants chose to kill a person directly in 1.75 of these dilemmas on average. That rate rose to 2.33 dilemmas on average for the highest dose of the drug. So, the drug did have a reliable influence on performance, but not a huge influence.

In addition, these studies involve only vignettes. It is hard to know exactly how people’s responses to stories relate to what they would actually do in a real situation.

However, the study does help to isolate the set of emotions that influence moral decisions. Anti-anxiety drugs like lorazepam influence anxiety and people’s response to threat. They do not have a broad-based effect on emotion overall. So, this research does push forward our understanding of the role of emotion in complex decisions.

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