By Shankar Vedantam
Washington Post Staff Writer
Friday, September 19, 2008
People who startle easily in response to threatening images or loud sounds seem to have a biological predisposition to adopt conservative political positions on many hot-button issues, according to unusual new research published yesterday.
The finding suggests that people who are particularly sensitive to signals of visual or auditory threats also tend to adopt a more defensive stance on political issues, such as immigration, gun control, defense spending and patriotism. People who are less sensitive to potential threats, by contrast, seem predisposed to hold more liberal positions on those issues.
The study takes the research a step beyond psychology by suggesting that innate physiological differences among people may help shape their startle responses and their political inclinations.
The study is part of a growing research effort to uncover the often hidden factors in people's political makeup. In recent years, a variety of studies have shown, for example, that voters are subtly biased in favor of attractive political candidates. Other research has probed how subconscious attitudes among undecided voters can predict whom they will eventually support, and how the speed with which voters answer poll questions can predict the depth of their commitment to one candidate or another.
"I was quite struck watching the conventions by the different tones," said co-author John Hibbing, a political scientist at the University of Nebraska at Lincoln, about the recent Republican and Democratic conventions. "The Republicans are waving placards saying, 'country first.' Democrats are not saying, 'country last,' but there is a concern that is visceral in one group but not another."
Hibbing and the other researchers stressed that physiology is only one factor in how people form their political views -- and far from the most important factor. Startle responses, moreover, cannot be used to predict the political views of any one individual -- there are many liberals who startle easily and many conservatives who do not. What the study did find is that, across groups of people, there seems to be an association between sensitivity to physical threats and sensitivity to threats affecting social groups and social order.
"We are not saying if you sneak up on someone and say 'Boo!' and see how hard they blink, that tells you what their political beliefs are," Hibbing said.
Nor is there the slightest implication that either liberals or conservatives are somehow abnormal for being more or less sensitive to threats: "We could spin a story saying it is bad to be so jumpy, but you can also spin a story saying it is bad to be naive about threats," he said. "From an evolutionary point of view, an organism needs to respond to a threat or it won't be around for very long. We are not saying one response is more normal than another."
Indeed, Hibbing and other researchers hope their study might help lower the volume of partisan invective in the presidential campaign: The research suggests that people who adopt political views you disagree with are not be stupid or irrational. Rather, they may arrive at their positions in part because they are predisposed to be more or less worried about risk.
The study, published in the journal Science, recruited 46 white partisan Republicans and Democrats in Nebraska. The volunteers were quizzed on their views on a variety of topics -- including the war in Iraq, same-sex marriage, pacifism and the importance of school prayer. All the questions were designed to test how strongly people needed to guard against various internal and external threats. None focused on economic issues.
Two months later, the researchers brought the volunteers into a laboratory and hooked them up to devices that measure a physiological factor that has long been known to be linked to threat response: moisture on the skin. When a person feels a threat, the skin releases more moisture -- and this can be picked up by sensors that measure skin conductance. The release of moisture does not involve conscious thought. It is an automatic response of the sympathetic nervous system, which controls many of the body's "fight or flight" reactions.
The researchers then showed the volunteers a number of images. Among them were images of a very large spider on the face of a terrified person, a person whose face had been bloodied, and an open wound filled with maggots. Compared with when they saw three placid images -- a happy child, a bowl of fruit and a bunny -- people who held more conservative political attitudes had a stronger startle response.
In a second experiment, the researchers startled the volunteers by playing a loud noise through headphones. This time, they measured how hard people blinked -- blinking is an automatic reflex to startling sounds. Again, people who startled more strongly tended to be those who held more conservative positions on political issues.
"There is some sort of broad left-right orientation that pervades not only our politics, but politics across the world and across time," said John R. Alford, another co-author of the study who is a political scientist at Rice University. "This variation could have biological underpinnings."