Social Psychology and Legal Writing: Hallmarks of Truthfulness

*This is the second post based on the work of Dr. James W. Pennebaker. Check out my first post for background on his research.

Social psychologist James W. Pennebaker has found that the language a person uses can suggest whether a person is lying or telling the truth. While no person, machine, or program currently in existence (including polygraphs) can detect lies at a rate any better than about 65%, Pennebaker’s studies suggest some hallmarks of truthfulness. According to Pennebaker, in general, people telling the truth use:

• More words and details
• Longer and more complex sentences (including use of     exclusive words such as except, but, and without)
• Fewer emotions
• Fewer verbs
• More self-references (I-words)

So why does the use of more words and details and more self-references signal honesty?

Pennebaker suggests that those telling lies speak and write more simply or straightforwardly because they are making up statements about things they did not experience. Truthtellers, on the other hand, use more words and greater detail because they are “distinguishing what did happen versus what did not, what they were thinking and what they were not thinking about, what was in the category and what was not in the category.”

And according to Pennebaker, I-words signal to the listener or reader that the speaker is paying attention to himself, and studies suggest that those who are more self-aware are more humble and honest.

Pennebaker notes that liars sometimes use performatives (statements about statements) to hide their lies. For example, consider this sentence: 

• Let me be clear: I did not collude with the Russians.

In that sentence, “let me be clear” is the performative. According to Pennebaker, a statement with a performative cannot be assessed for truthfulness because the part of the statement that we care about (here, the assertion about a lack of collusion with Russia) is not directly asserted.

Pennebaker offers a statement by President Bill Clinton as an example. At a January 1998 press conference, Clinton said:

• I’m going to say this again: I did not have sexual relations with that woman, Miss Lewinsky.

The nation later learned, of course, that Clinton did have sexual relations with Lewinsky. But he was not lying when he said, “I’m going to say this again” because he did, in fact, say it again.

Self-deception is also an issue. People (whether intentionally or unintentionally) deceive themselves, often by expressing overconfidence, says Pennebaker.

• I am absolutely certain that I can settle the case for $50,000.

To most, this sentence appears (and likely is) less truthful than the following sentence:

• There is a good chance I can settle the case for $50,000.

Interestingly, juries may be less likely to believe the very language that signals truthfulness. Take, for example, the following sentences from a crime victim:

• I am 100% sure that the defendant is the man who entered the store and robbed it.

• The defendant is the man who entered the store where I was working at 9 p.m. on August 31, 2016, brandished a 9 mm gun, and robbed me of all the money in the cash register, about $350.

All other things equal, jury members may find the definitiveness of the first statement more credible than the second, even though the second is more detailed and appears more reasonable (who, really, can be 100% sure of anything?), and, in the second, the speaker refers to himself more.

The Lying Words chapter of Pennebaker's The Secret Life of Pronouns may be of particular interest to criminal lawyers. In that chapter, Pennebaker describes a test he and a private investigator performed. The investigator gathered sworn testimony from two groups of criminal defendants—those who were convicted but later exonerated by DNA or other overwhelming evidence and those who were acquitted but later convicted of perjury. Members of the first group, thus, were “bad” at telling the truth while members of the second were “good” at lying.

The results of that study were consistent with Pennebaker’s earlier findings, specifically with respect to I-words. In their testimony, the later-exonerated defendants used more first-person singular pronouns; that is, I-words appeared to signal innocence, as did bigger words and more detailed descriptions. The defendants later convicted of perjury, on the other hand, used more third-person pronouns, in an apparent effort to shift blame to others.  

So, the next time you're assessing the writing or speech of others, look for Pennebaker's hallmarks of truthfulness. They might help you sniff out a liar!