When pondering a decision or trying to convince others, think carefully about your metaphors. The implicit information may subtly influence decision making.

A study published in January in PLOS ONE examined how reading different metaphors—“crime is a virus” and “crime is a beast”—affected participants' reasoning when choosing solutions to a city's crime problem. Those who read the beast metaphor were more likely to opt for a direct approach emphasizing enforcement, whereas the virus metaphor elicited a preference for a systemic, reform-focused solution. A follow-up survey indicated that many participants did not remember the metaphor they read, and none thought a metaphor could have influenced their reasoning.

“People don't consciously ponder the ways in which crime is like a virus or beast,” says one of the study's authors, Paul Thibodeau, who is now a psychology professor at Oberlin College. “Instead metaphors subtly structure the way they understand the issue being described.”

Previous brain-imaging research has shown that interpreting metaphors requires a variety of areas on both sides of the brain, compared with literal language, which is processed in known language areas in the left hemisphere.

Scientists do not yet know how exactly this pattern affects reasoning, but they suspect that the brain triggers related concepts when processing a metaphor's meaning. Thibodeau recommends giving more thought to the metaphors you use and hear, especially when the stakes are high. “Ask in what ways does this metaphor seem apt and in what ways does this metaphor mislead,” he says. Our decisions may become sounder as a result.