Psychology has known for quite some time that keeping secrets causes certain physiological effects. Secret keepers remain in heightened states of arousal, which can have deleterious effects on their health, for fear of being found out. They become paranoid, anxious, and according to recent research, even change their language patterns.

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Recent studies from the University of Texas at Austin and Carnegie Mellon University are unveiling a set of findings that people who keep secrets routinely and unconsciously change their speech patterns to help cope with the inner turmoil. These patterns were observed through e-mail; however, the small-scale significance has large implications for the ways in which public figures have changed their behavior prior to major historical events.

Finding The Secrets Within The Studies

In one study still under review, James Pennebaker and his colleagues at UT Austin recently tested to see whether people exchanged e-mails differently if they were keeping a secret, specifically looking for cases where people became hypervigilant or more withdrawn.

Their first study tested 16 women with depressive symptoms and 15 healthy subjects, all of whom shared the majority of their e-mails over the previous year. The team then parsed through the messages, checking for pronoun usage and e-mail frequency. Pennebaker's extensive research into pronoun usage suggests that the prevalence of "I" and "me" in depressive patients often reflects a masking effect.

"People who are depressed spend much of their time masking it," Pennebaker noted. "They use communication strategies to come across as chipper."

The women who were depressed sent more e-mails, at greater length, than the women whose symptoms were in remission or otherwise healthy. The psychologists reasoned that an examination of such behaviors would demonstrate depressed subjects' desire to keep their condition under wraps.

Separate research from Carnegie Mellon shows that this depressive masking behavior could, in fact, lead secret-seeking sleuths astray. Led by psychologist Yla Tausczik, the study recruited 62 adults who admitted they were keeping a life-altering secret and, like the former study, volunteered to share a year's worth of emails, including some from before the secret formed.

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In Tausczik's study, the secret keepers also wrote more e-mails, at greater length, than those who hadn't kept a secret. However, the two studies differed in how often the deceptive group used "I" and "me" pronouns. Whereas the UT study saw greater usage, the Carnegie Mellon study saw secrecy decreasing its usage.

In a recent interview with Scientific American, Pennebaker remarked on the unique challenge of mining other people's speech for clues to their secrecy, particularly as they pertain to speech patterns across sexes.

"You can't help but marvel at the fact that we are all bombarded by words from women and men every day of our lives and most of us have never 'heard' these sex differences in language," he said. "Part of the problem is that our brains aren't wired to listen to pronouns, articles, prepositions, and other 'junk' words. When we listen to another person, we typically focus on what they are saying rather than how they are saying it."

In this way, Pennebaker says the key to discovering a person's concealed dirty laundry could be found in "language-style matching," the process of two people using similar words and speech patterns in their interactions.

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Even though secret-keepers were sending more e-mails than the other group, their language-style matching scores were lower.

"I think they're sending these emails to test their social networks-are we on the same page?" argued Pennebaker. "They're sending out emails to socially connect, but they're not connecting well."

The Public Figure Effect

Pennebaker argues that these cues cross over to large-scale political events throughout history. In the months before declaring war on Iraq, President George W. Bush used fewer singular pronouns — a telltale sign someone could be keeping a secret — such as "I," "me," and "my." The same phenomenon was found in Harry Truman before he dropped the bomb on Hiroshima.

And in an unpublished analysis of Dzokhar Tsarnaev's tweets beginning in October 2012, the alleged Boston Marathon bomber used far fewer messages with "I." This all took place shortly after his more radical brother returned from a six-month trip to Russia and began a string of YouTube threats.

"Pennebaker suggests that around this time Tsarnaev convinced himself to bomb the marathon, and the drop in personal pronouns reflects his newly acquired secret," Scientific American reports.

Such a finding has great implications for the future of speech data analysis. Given what Pennebaker and like-minded psychologists know about the deep truths behind tiny words, researchers have confidence that the field can only be growing.

"I think one advantage I have had in my career is that I've got a short attention span. If something new and exciting bubbles up in our data, I will likely drop what I'm doing and try to understand it," Pennebaker said. "It's a wonderful time to be alive."