Park, Hee Sun

Veracity Effect

Hee Sun Park's most influential contribution to deception research was her 1999 paper describing the “veracity effect,” which is the idea that [Page 748]because people are typically truth biased, they tend to get truths right more often than lies in deception detection experiments. She developed the idea while taking a class on deception as a graduate student.

Prior to the publication of the paper on the veracity effect, most research looking at deception detection accuracy averaged across truths and lies when calculating accuracy. This research found that people are typically slightly better than chance at distinguishing between truths and lies. The average accuracy in such research is just under 54 percent. That research also found that people are usually truth biased; that is, people guess truths more often than then they guess lies.

Park reasoned that because people are more likely to believe than disbelieve (that is, they are truth biased), they would be right about truths more often than about lies. People would be much better than 50/50 recognizing honest messages and below 50/50 recognizing lies. Consequently, the conclusion that people were 54 percent accurate at deception detection was potentially misleading. A more careful conclusion required looking at accuracy for truths and lies separately.

In 1999, teaming up with Timothy R. Levine and Steven McCornack, Park published the findings in a series of four experiments documenting the veracity effect in Communication Monographs. Accuracy for truths ranged from 75 percent to 82 percent, while accuracy for lies fell between 31 percent and 39 percent. How often people made correct truth-lie judgments was impacted by the veracity of the message they judged. People most often correctly believed truthful messages, while incorrectly believing lies. Following the publication of the veracity effect study, it has become more common for research to report accuracy for truths and lies separately.

...