Recent research published in journals psychophysiology When a person is not confident in their performance and yet tries to brag about it, it suggests that their body is still showing subtle signs of lying. This study provides evidence that uncertainty drives individuals to a middle ground between honesty and deception. This middle ground allows individuals to increase their self-esteem while being less physiologically stressful than outright lies.
Humans often navigate complex social situations by deciding whether to be honest or bend the truth for personal gain. Telling an obvious lie usually causes physical changes, such as increased sweating, whereas being completely honest tends to keep your body in a calmer state. Both of these actions depend on the person knowing the actual facts of the situation.
However, daily life is full of ambiguous situations in which people do not have all the facts. Scientists wanted to understand what happens to a person’s body and self-confidence when they try to present themselves in the best light possible, despite the lack of clear information. They aimed to see whether people behaved as if they were telling the truth or whether their bodies responded to uncertainty as if they were actively deceiving someone.
“In our laboratory, we constantly like to remind ourselves that humans are social creatures, defined by a strong desire to belong to and be recognized by others. We decided to explore this topic because we were interested in exploring how individuals use deception to strengthen their perception of the persona of others,” explained study authors Giulia Romano Cappi and Olga Dal Monte from the University of Turin.
Researchers recruited 32 healthy volunteers in Italy. The sample included 17 women and 15 men between the ages of 19 and 32. In a laboratory setting, each participant sat at a computer opposite an actor who was introduced as a lie detection expert.
During the experiment, participants completed a series of logic puzzles on a computer. After finishing, they guessed how well they did by choosing whether their performance was the worst or the best. The computer then provided randomly generated feedback to the students regarding their scores.
This feedback led to the creation of three different conditions for the experiment. In the truth condition, the computer told the participants that they definitely got the highest score. In the deception condition, the computer told them it definitely gave them the worst score.
The third scenario serves as an uncertainty condition. The feedback here is ambiguous, with participants stating that they probably performed their best, or perhaps their worst. Therefore, participants could not get a clear answer about their actual abilities.
Regardless of the feedback they received, participants were instructed to convince the lie detection expert that they had achieved the highest score. They had to answer “yes” to a series of questions from experts, culminating in a question about whether they believed themselves to be one of the top performers. To increase motivation, the scientists told participants that they could win prizes for their persuasiveness and speed of work.
Throughout this interaction, researchers tracked participants using special sensors. They measured skin conductance, which tracks minute changes in sweat gland activity to determine physiological arousal and stress. After each round, participants rated their own confidence on a scale of 0 to 100 about how well they had convinced the experts.
The scientists also used sensors on the face to monitor tiny electrical signals from specific muscles. They tracked the muscles above the eyebrows, which are used when frowning, and the muscles in the cheeks, which are used when smiling. This allowed the researchers to see whether participants were trying to hide their facial expressions while talking to the experts.
For their analysis, the scientists focused specifically on trials in which participants initially guessed they had performed well before receiving feedback. This allowed the researchers to observe behaviors associated with self-enhancement. Self-enhancement is the natural human tendency to overestimate personal qualities in order to gain social approval.
The data revealed differences between the three scenarios. Participants reported having the lowest confidence in their ability to persuade experts when they had to claim the highest score even though they knew they were performing poorly. Their confidence reached its peak when they received positive confirmation of their highest score.
In uncertain situations, participants’ confidence levels fell in the middle. They felt more convincing than when they told an outright lie, but less convincing than when they told the absolute truth. This suggests that the lack of clear facts led them to partially believe their exaggerated claims.
Physiological data reflected these confidence ratings. Scientists have found that active deception causes a significant spike in sweat gland activity, indicating heightened physiological arousal. Telling the truth led to lower skin conductance and a calmer physical state.
When participants were unsure of their actual performance, sweat gland activity again fell between the two extremes. The body showed minor signs of stress that were higher than in the truth condition but lower than in the deception condition. Physiological evidence shows that even if a person does not know the whole truth, traces of deception still exist at an unconscious level.
“In this study, we combined behavioral and physiological measurements to investigate a new and controversial phenomenon within a socially interactive paradigm: self-deception,” the researchers told PsyPost. “Our results show that both the behavioral and physiological responses associated with self-deception occupy an intermediate position between those observed in truth-telling and intentional deception, thereby providing new insights into the mechanisms underlying the process of self-deception.”
“Furthermore, the observed dissociation between explicit and implicit responses provides valuable evidence regarding the complex and still debated relationship between physiological and psychological processes in the context of truthful, deceptive, and self-deceptive tendencies.”
Facial muscle sensors showed no significant differences between the three scenarios. Participants did not show increased frowning or smiling activity when they told a lie compared to when they told the truth. Scientists believe this may have happened because the task did not evoke strong positive or negative emotional expressions that would cause specific muscle movements.
Researchers argue that truth and deception are not simple binary choices. Instead, they operate on a continuous spectrum. When faced with ambiguous situations, people may tell partial lies to protect their self-image.
These findings provide evidence that uncertainty promotes a type of self-deception, allowing people to increase their own confidence while minimizing the physical stress typically associated with lying.
“When we talk about deception, it’s not black and white,” the researchers said. “Sometimes people lie to themselves before lying to others in order to preserve their image.”
This study has several limitations that should be considered. The sample size was relatively small, so the statistical effects observed were modest. Future research should gather larger and more diverse groups of people to see if these patterns hold across different ages and cultures.
This study also only targeted Italian university students. Different cultural attitudes toward bragging and lying can alter the body’s response to ambiguous situations.
“Individual differences may be a limitation here; each of us may approach deception differently,” the researchers noted. “Some people may be justified in lying to others, while others are more harsh about it. These differences should be kept in mind.”
Looking to the future, scientists want to explore the underbelly of these complex social interactions. “When we talk about deception, we often focus on liars,” they said. “It would be interesting to shift the focus to the person being lied to and see if and how detection of deception changes based on the liar’s level of consciousness.”
The study, “The body knows what the mind doesn’t: Uncertainty affects physiological markers of deception,” was authored by Giulia Romano Cappi, Ilaria Mirrisenna, Alessandro Mazza, and Olga Dal Monte.
