Research on Lies Uncovers the Truth

Lies flow from the mouths of millions every day, but according to new research, the cognitive mechanics behind how a person is able to recall the lies they've told depends on how exactly they lied.

Researchers looked at two sorts of lies -- false descriptions and false denials. The former involves wholesale fabrication of events or details that are not true, whereas the latter sort simply denies that something did or did not happen.

Sean Lane, an associate professor of psychology at Louisiana State University, found that how a person remembers a lie is determined by the type of lie told.

Lane found that the more complex a lie is, the easier the liar will be able to recall it. Completely fabricated details or events require the liar to remember a variety of information, and Lane has found that these false descriptions remain more accessible and more durable in the liar's memory because they are taxing to cognitive power.

"If I'm going to lie to you about something that didn't happen, I'm going to have to keep a lot of different constraints in mind," Lane said.

False descriptions require the liar remember all of what they've said, how plausible the lie seems, the degree of detail they offered while telling the lie and how they've adapted their story to win over an unconvinced listener.

"As the constructive process lays down records of our details and descriptions, it also lays down information about the process of construction," Lane said. When Lane asked his test subjects to recall the false description they had fabricated 48 hours earlier, their memories of how they lied were largely accurate.

It was not the same for liars using the tactic of false denial; those sort of lies are often quick and the cognitive demand they require is much smaller. Lane's test subjects had a hard time remembering their own false denials after 48 hours.

"I'm not constructing details. But I'm also not going to remember the act [of lying] because there's not much cognitively involved in the denial," Lane said.

Forensic interrogators who use a series of rapid-fire questions in their investigation have something to gain from the research, as it shows a guilty suspect is more likely to forget a false denial and therefore is more likely to contradict himself on the same information later on.

However, the research indicates a haunting implication for the innocent. Lane's test subjects showed difficulty remembering if the denials they made were true or false, which suggests a subject who is repeatedly asked to make a truthful denial may wind up confusing themselves into misaligning the truth.

"They're telling the truth -- they're denying -- but later this thing seems familiar," Lane said. "They're confusing the familiarity of the repetition [with the truth], not realizing that those repeated denials are what makes it seem familiar 48 hours later."

Lane's research is to be published in the Journal of Applied Research and Memory Cognition.