Lafayette, California is a small, affluent town situated in a cluster of rolling hills twenty miles to the east of San Francisco. In 2006, a local anti-war protestor erected a memorial to the American casualties of the Iraq War on one of those hills, along Highway 24 and across from the Lafayette BART station. He believed that he could increase opposition to the war by “remind(ing) people there are lives being lost, families being devastated.”

The memorial aroused passionate feelings, including city council meetings devoted to the legality of the display and some heated face-to-face confrontations. Conservative members of the community found it offensive and asked that it be removed. Though Obama recently ordered a major troop withdrawal, the wars are ongoing and the solemn memorial still stands today, consisting of thousands of four-foot-high white crosses, as well as a sign prominently displaying the number of soldiers who have died.

However, an upcoming paper demonstrates that there is a chance that such displays can actually increase support for the war. In a pair of experiments to be published in the Journal of Experimental Social Psychology, researchers from Washington University and the University of Michigan show that statistics about the number of casualties in an ongoing war can lead to increased support for the war if one is in what the authors term a “don’t waste” mindset. The authors report that people in such a mindset are more likely to be susceptible to making a “sunk-cost” fallacy. In other words, the casualties are seen as an initial investment, causing people to want to assure that those soldiers didn’t die in vain.

The “sunk-cost” fallacy is a common type of irrational human behavior. For example, if staying home will make you happier than going to a movie, reason dictates that you should stay home. However, when it comes to rational decision-making, humans (and politicians) often use irrelevant information to help them decide -- such as whether they’ve already spent any resources. Someone who wants to stay home, but who has already purchased a movie ticket, will tend to opt for going to the movie because of the resources already devoted to the event. Somewhat counter-intuitively, then, a “don’t waste” mindset predicts that increased troop casualties would result in increased support for the war.

Research on public support for wars has generally shown that Americans are tolerant of soldier casualties. That is, the sheer number of deaths and injuries is a less important factor for support than other aspects of a conflict, such as expectations of victory. Moreover, it is generally assumed that when casualties do influence attitudes, they will do so negatively. The research supporting this assumption, though, suffers from two weaknesses. First, it is ambiguous, with different researchers finding different relationships, and second, it is entirely correlational.

The problem with correlational research is that, unlike an experiment, it cannot establish whether there is a causal relationship between factors. For example, the number of boating accidents and murders are correlated. However, an experiment would reveal that boating accidents do not cause murders, nor murders boating accidents – but rather that a third variable, warm weather, leads to increases in both.

The present paper sought to establish just such a causal relationship. The scientists conducted two experiments. In each, some participants were randomly assigned to read an article about one of the ongoing wars in the Middle East while the remaining participants read a control article about the upcoming warm weather. Prior to reading these articles, half the participants were randomly put into a “don’t waste” mindset by answering questions about a series of sunk-cost scenarios. One scenario, for example, had participants imagine that they joined an expensive tennis club and developed a painful tennis elbow. They were then asked whether or not they would keep playing. The other half of the participants answered questions about similar scenarios that did not include the potential loss of initial investment.

Following these manipulations, participants were given a questionnaire evaluating their attitudes toward the conflict. Across both experiments, participants who read the article detailing troop casualties had statistically more favorable attitudes toward the armed conflict when they were primed with the “don’t waste” mindset.

Our decision-making machinery is highly susceptible to these kinds of glitches. They are unfortunate side effects of the way our mind functions. As shown in this experiment, the context can increase or decrease the likelihood of experiencing such glitches.

In a broader sense, this work is another demonstration that individuals should be aware of the effect that context has on their thinking. When a news report mentions the level of support for an ongoing conflict, or for a presidential or congressional decision about a conflict, consider what other external factors might be driving that number up or down. For instance, are people worried about saving money in a tough economy? Has there been recent public discourse on the wasting of natural resources? This paper demonstrates that co-occurring factors like these could prime a “don’t waste” mindset, leading to significant changes in national attitudes toward apparently unrelated phenomena, like support for a war.

The war memorial in Lafayette was established with the hopes that it would remind people of the human costs of engaging in war. No doubt, it has succeeded in that. However, the protestor who established it, and the less pacifistic individuals who have fought for its removal, should know that the effect of this display will depend on the context in which it is encountered. Occasionally, the context will lead to effects which are counter to what one might expect.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.