Polish researchers find a simple gesture not only conveys the impression of honesty, but also prompts more truthful replies.

Take a moment and place your hand over your heart. How does it make you feel? Honest? Virtuous?

Well, that feeling may not be illusory. Recent research from Poland finds that simple gesture not only conveys the impression of honesty—it also prompts people to behave in more ethical ways.

That’s the conclusion of Michal Parzuchowski and Bogdan Wojciszke of the University of Social Sciences and Humanities in Sopot. Their findings, the latest from the fascinating world of embodied cognition, are published in the March issue of the Journal of Nonverbal Behavior.

The researchers describe four experiments, the first of which confirms that Poles associate the hand-over-heart gesture with honesty. They do not find this surprising, given that, in Poland, the phrase “with hand over heart” is an “expression of honesty used at the end of any dubious statements.”

The second experiment featured 37 Polish university students who listened to parts of an audio recording of a job interview. In it, the applicant makes a series of statements that are difficult to take at face value, such as “I have never been late for work” and “I have never even argued with members of my family.”

"When presented with an opportunity to lie about someone’s appearance, people who put their hands over their hearts remained more honest, even if it meant being impolite."

As they listened, the students looked at one of two photographs of the speaker. Half saw a shot of her standing with both of her hands placed behind her back; the others saw a similar image, except her right hand was placed over her heart. All then were asked to rate the extent to which they believed her answers.

The results: The woman was considered more believable by participants who saw the image of her with her hand on her heart. This suggests the signal of honesty is “spontaneously included in an impression of the signaler,” the researchers write. “A person producing this signal is perceived as more credible, even if her statements are not very credible.”

The third experiment featured 48 university students who were instructed to rate the looks of a series of women seen in photographs. The women were of moderate to low attractiveness; they were presented as friends of the experimenter, who would presumably be insulted if the scores came in too low.

Half the participants made their assessments while holding their right hand over their heart; the others placed the hand on their hip. (They were told the gesture increased their “cognitive load,” and the researchers wanted to discover if this mental stress affected their judgment.)

“The unattractive faces were rated significantly lower by participants keeping their hand on their heart, rather than their hip,” the researchers report. “When presented with an opportunity to lie about someone’s appearance, people who put their hands over their hearts remained more honest, even if it meant being impolite.”

In the final experiment, 52 students solved a series of math problems. Seventeen of them wrote down their solutions. But the rest “had their dominant hands occupied with a different activity, which meant they had to “remember the number of solved problems and report them later.”

Specifically, they were asked to perform the exercise while wearing a “breathing monitor band.” Participants held the device over their chests using one of two gestures: putting their right hand on their left shoulder, or—you guessed it—placing their right hand over their heart.

The students had an incentive to inflate the number of problems they had solved—one randomly selected participant received a cash prize for each correct answer—and those who had their hands on their shoulders did so, “claiming 45 percent more solved matrices than the other two groups.”

In contrast, the people with their hands on their hearts scored themselves honestly, thereby “behaving in accordance with moral standards that are linked with the meaning of this hand placement.” Thoughts of cheating were apparently overridden by the presumably unconscious impulse to act in a way that was congruent with the gesture.

“Bodily sensations influence the way we think, feel, and act,” the researchers note. “The mere experience of a bodily sensation may activate the concept associated with it; this in turn may shape information processing, and behavior.”

The researchers note that different cultures have different gestures conveying honesty and trustworthiness. They speculate that, in the U.S., raising one’s right hand, as happens when you take an oath to tell the truth, would likely have a similar effect.

In an email, Parzuchowski cautioned against interpreting these results as a "truth serum."

"One strong limitation of our studies is that you would only receive more truthful response (at least this kind of situation we tested this manipulation on) if you engage your respondent in the hand-on-heart gesture just before, or while, they need to make a decision while they are tempted to cheat (without a chance of being caught)," he noted.

"Also, the idea behind HOH as a bodily feedback association between the gesture and the abstract concept is learned very early in (childhood) development, probably even before verbal development takes place. Thus I would suggest that people need not only to learn this abstract meaning of the gesture (to be linked with honesty), but also need to observe others performing this gesture, so that they would learn the meaning and use it as an automatic cue."

Of course, Americans periodically place their hands on their hearts to signal patriotism and solidarity (say, while reciting the pledge of allegiance). Do we unconsciously link that gesture with the notion of being an upstanding citizens? And if so, is the association strong enough to influence our behavior, as it apparently does for Poles?

We'll have to wait for additional research, but it'll be fascinating to read. Cross my heart.*

*UPDATE — March 24, 2014: We've added comments to the end of this post from Michal Parzuchowski, the researcher, who sent a follow-up email after we originally published.