The results might seem to suggest that conservative voters—those who wish to maintain the status quo—tend to be hardwired to be more easily startled.
But Smith cautioned that many important political issues, such as economic concerns, were not tested and that the research was simply an intriguing first step.
"We're not willing to say this separates liberals and conservatives," Smith said.
But Duke University political scientist Evan Charney said that such studies run the risk of "pathologizing conservatism and I say that as a left-wing liberal."
The study could be read as, "Conservatives are a hell of a lot more threatened than liberals," Charney said.
"But if the results had come out the other way, we might be reading [interpretations] that liberals are more attentive than conservatives or more concerned than conservatives."
It's unclear whether the images caused a "threatened" response, Charney said. Other emotional reactions could have produced the same skin responses.
Charney has gone so far as to submit a letter to Science in which he notes that the data "also could have been measuring disgust (a reasonable response to a picture of a bloody face, a spider on a person's face, and a leg filled with maggots), surprise, confusion, consternation, discomfort, and a host of other emotional responses."
Charney further suggested that the physical reactions might actually indicate intense concern for an individual thought to be in distress, or perhaps even sympathy and empathy.
Congenitally Conservative? Born Liberal?
Political and social scientists have long held that political attitudes are shaped by upbringing and life experience—nurture not nature.
But some recent research suggests that genes could help to predetermine how people instinctively respond to emotional issues, making people predisposed to inherit specific social views.
"We thought an obvious place to [explore the link] was to look at relevant biological systems, which have a genetic component," study leader Smith said.
"So if you can link those biological systems to political attitudes and behaviors, that [biological system] may be one of the mechanisms that fill in the gap between genes and political attitudes."
Though the study suggests the existence of such a link, Duke's Charney remains skeptical about the extent to which genes govern attitudes.
"I think the primary reason is the exact reason someone speaks English instead of French," he said. "It's not genetic, it's the culture in which they were born and raised."
SOURCES AND RELATED WEB SITES