Truth-default theory centers on the idea that people tend to accept what others say to be honest and this defaulting to truth has adaptive values for both individuals and the collective. Tim Levine and colleagues developed the theory in an attempt to make sense of research findings showing that people are terrible lie-detectors and their detection accuracy was only slightly above chance. Through a series of studies across diverse populations, researchers found that most communication in daily life is honest; that is, most people communicate to be understood rather than being deceitful. People do not lie unless telling the truth is inconvenient or interferes with achieving certain goals (Levine, 2014). Because of the low occurrence of deception in real life, our tendency to believe our interaction partners serve us well in daily social interaction. By assuming what we hear to be true, we save cognitive energy and resources that could be better invested elsewhere. Society as a whole also benefits because social coordination and cooperation is made possible and more efficient when people do not deliberately question everything other people say. At the same time, truth default also makes people vulnerable to occasional deceit. People do not actively question the truthfulness of others’ communication unless they are given a reason for suspicion. And as it turns out, we aren’t very accurate at making honesty/deception judgments when relying solely on observing someone’s nonverbal behavior or scrutinizing the content of their communication. What does help us detect a lie, the theory argues, is when we pay attention to contextualized communication content. This is usually achieved through comparing what is said to third party information, external evidence, our preexisting knowledge, or the target person’s later confession (Park et al. 2002). A lie can also be effectively detected when we strategically question the potential liar to expose the inconsistencies in their statements (Levine et al., 2014). Overall, the theory provides a unique account of the psychology of lying and deception detection. Recent research has also extended the truth bias phenomenon into contexts such as intergroup communication (Fan et al., 2022), misinformation (Zimmerman et al., 2022), generative AI (Markowitz & Hancock, 2023), among others. 

References and other suggested readings:  

Fan, X., Griffin, D. J., & Tagg, E. P. (2022). Lie judgment trigger sensitivity and truth-bias: truth default theory in intergroup communication. Communication Quarterly, 70(4), 448–468. https://doi.org/10.1080/01463373.2022.2079994  

Levine, T. R. (2014). Truth-default theory (TDT) a theory of human deception and deception detection. Journal of Language and Social Psychology, 33(4), 378–392.  https://doi.org/10.1177/0261927×14535916  

Levine, T. R. (2022). Truth-default theory and the psychology of lying and deception detection. Current Opinion in Psychology, 47, Article 101380. https://doi.org/10.1016/j.copsyc.2022.101380 

Levine, T. R., Clare, D. D., Blair, J. P., McCornack, S., Morrison, K., & Park, H. S. (2014). Expertise in deception detection involves actively prompting diagnostic information rather than passive behavioral observation. Human Communication Research, 40(4), 442–462. https://doi.org/10.1111/hcre.12032  

Markowitz, D. M., & Hancock, J. T. (2024). Generative AI are more truth-biased than humans: A replication and extension of core truth-default theory principles. Journal of Language and Social Psychology, 43(2), 261–267. https://doi.org/10.1177/0261927×231220404  

Park, H. S., Levine, T., McCornack, S., Morrison, K., & Ferrara, M. (2002). How people really detect lies. Communication Monographs, 69(2), 144–157. https://doi.org/10.1080/714041710   Zimmerman, T., Njeri, M., Khader, M., & Allen, J. (2022). Default to truth in information behavior: a proposed framework for understanding vulnerability to deceptive information. Information and Learning Sciences, 123(1/2), 111–126. https://doi.org/10.1108/ils-08-2021-0067

Interpersonal deception theory explains the process and outcomes of deception in interpersonal interaction. The theory argues that deception is a goal-oriented, intentional, and strategic communicative behavior. People lie to satisfy a host of goals, such as maintaining a positive image, preventing relational conflict, avoiding awkward social situations, protecting one’s privacy, or influencing others to comply with a request. According to the theory, deception is a dynamic process where both the deceiver and the receiver are active participants in deceptive conversations. For deceivers, they think about how the receiver may react to the deceit, how they can appear credible, and how they can adapt to the receiver’s feedback or suspicion. Importantly, deceivers manage not only the content of the message (e.g., hide, distort, omit, or avoid information), but they also adjust their nonverbal behaviors and language style to put forward a credible self-presentation. Receivers also play an important role in deception, such that their expectations or goals of the interaction, knowledge of the other person or the relationship, communication skills in deciphering social and emotional cues, or suspicion of the messages shape how the interaction goes. For example, a receiver may become particularly vigilant if he/she is uncertain whether the sender is telling the truth or not, strategically adapt his/her communication style to get the truth out, or provide feedback to the sender that conveys either acceptance or skepticism. As the theory argues, the sender and the receiver of a deceptive episode mutually influence one another over the course of an interaction and shape the outcomes of deception. The theory provides a useful lens for examining deception in a variety of contexts, such as linguistic traces of deception in online dating profiles (Toma & Hancock, 2012), motives for deception in romantic relationships (Guthrie & Kunkel, 2013), and deceptive behaviors conducive to online fraud (Maimon et al., 2019).  

References and other suggested readings:  

Buller, D. B., & Burgoon, J. K. (1996). Interpersonal deception theory. Communication Theory, 6(3), 203–242. https://doi.org/10.1111/j.1468–2885.1996.tb00127.x 

Burgoon, J. K. (2015). Rejoinder to Levine, Clare et al.’s comparison of the Park–Levine probability model versus interpersonal deception theory: Application to deception detection. Human Communication Research, 41(3), 327–349. https://doi.org/10.1111/hcre.12065  

Guthrie, J., & Kunkel, A. (2013). Tell me sweet (and not-so-sweet) little lies: Deception in romantic relationships. Communication Studies, 64(2), 141–157. https://doi.org/10.1080/10510974.2012.755637 

Maimon, D., Santos, M., & Park, Y. (2019). Online deception and situations conducive to the progression of non-payment fraud. Journal of Crime and Justice, 42(5), 516–535. https://doi.org/10.1080/0735648X.2019.1691857 

Thomas, J. Y., & Biros, D. P. (2020). An empirical evaluation of interpersonal deception theory in a real-world, high-stakes environment. Journal of Criminal Psychology, 10(3), 185–199. https://doi.org/10.1108/jcp-07-2019-0025  

Toma, C. L., & Hancock, J. T. (2012). What lies beneath: The linguistic traces of deception in online dating profiles. Journal of Communication, 62(1), 78–97.  https://doi.org/10.1111/j.1460–2466.2011.01619.x  Wise, M., & Rodriguez, D. (2013). Detecting deceptive communication through computer-mediated technology: Applying interpersonal deception theory to texting behavior. Communication Research Reports, 30(4), 342–346. https://doi.org/10.1080/08824096.2013.823861