One study, from 2010, found that physicians use metaphors in almost two-thirds of their conversations with patients who have serious illnesses. Physicians who used more metaphors were seen as better communicators. Patients reported less trouble understanding them, and felt as though their doctor made sure they understood their conditions.

Metaphors are a fundamental mechanism through which our minds conceptualize the world around us, especially in the face of complexity. But evidence suggests they do more than explain similarities—they can invent them where they don’t exist, and blur the lines between the literal and the figurative.

One such example comes from research conducted by Lawrence Williams and John Baugh, suggesting that people often confuse physical warmth with social warmth. In their study, a researcher asked participants to briefly hold either a hot or iced coffee on their way to the experimental room, seemingly before the experiment had begun. Later participants read an ambiguous description of an anonymous individual. Those who had held the hot coffee were more likely to rate that individual as having “warmer” personality traits like generosity and compassion. In another study, participants who held the warm coffee were more likely to choose to give a gift to a friend than to take it for themselves.

Other work done by Chen-Bo Zhong and Katie Liljenquist explores the Macbeth Effect, in which suggestions of moral impurity stimulate a desire to cleanse oneself physically in an attempt to wash away one’s sins. In a series of studies, the authors found that participants prompted to think of their own or others’ moral indiscretions were more likely to rate cleaning products as more desirable than other products, and were twice as likely to choose an antiseptic wipe over a pencil when offered a gift for participating. Even more interesting is participants’ unspoken perception that washing their hands restores their moral integrity. Those who were reminded of their unethical behavior and had the opportunity to clean their hands after were almost 50 percent less likely to help out with another study, suggesting that subconsciously they felt physical cleansing had absolved them of previous unethical behavior.

These unconscious processes seem to play out even when we analyze complicated, cerebral issues. In another study, researchers asked people to help solve a city’s crime problem, which was described either as “virus infecting a city” or a “wild beast preying on a city.” People who got the “virus” frame were far more likely to propose solutions involving social reform to address root causes like poverty and lack of education, while those receiving the “beast” frame were more likely to propose solutions involving catching criminals and enforcing laws more strictly. Almost none of the subjects identified the metaphorical frame as being important to their decision-making process, instead crediting hard data like statistics and facts. But the magnitude of the metaphor effect was larger than pre-existing differences of opinion between liberals and conservatives.