Are there hidden messages in your emails? Yes, and in everything you write or say, according to James Pennebaker, chair of the department of psychology at the University of Texas at Austin. Pennebaker has been a leader in the computer analysis of texts for their psychological content. And in his new book, “The Secret Life of Pronouns,” he argues that how we use words like “I,” “she,” and “who” reveal secrets of our psychology. He spoke recently with Mind Matters editor Gareth Cook.

COOK: How did you become interested in pronouns?

PENNEBAKER: A complete and total accident. Until recently, I never thought about parts of speech. However, about ten years ago I stumbled on some findings that caught my attention. In the 1980s, my students and I discovered that if people were asked to write about emotional upheavals, their physical health improved. Apparently, putting emotional experiences into language changed the ways people thought about their upheavals. In an attempt to better understand the power of writing, we developed a computerized text analysis program to determine how language use might predict later health improvements. In other words, I wanted to find if there was a healthy way to write.

Much to my surprise, I soon discovered that the ways people used pronouns in their essays predicted whose health would improve the most. Specifically, those people who benefited the most from writing changed in their pronoun use from one essay to another. Pronouns were reflecting people’’s abilities to change perspective.

As I pondered these findings, I started looking at how people used pronouns in other texts -- blogs, emails, speeches, class writing assignments, and natural conversation. Remarkably, how people used pronouns was correlated with almost everything I studied. For example, use of first-person singular pronouns (I, me, my) was consistently related to gender, age, social class, honesty, status, personality, and much more. Although the findings were often robust, people in daily life were unable to pick them up when reading or listening to others. It was almost as if there was a secret world of pronouns that existed outside our awareness.

COOK: What would make you think that the use of pronouns would be meaningful?

PENNEBAKER: Never in a million years would I have thought that pronouns would be a worthwhile research topic. I ran study after study and initially found large and unexpected differences between people in their pronoun use. In hindsight, I think I ignored the findings because they didn’’t make sense. One day, I lined up about 5 experiments that I had conducted and every one revealed the same effects. It was that day that I finally admitted to myself that pronouns must be meaningful.

COOK: What differences have you found between men and women?

PENNEBAKER: Almost everything you think you know is probably wrong. Take this little test. Who uses the following words more, women or men?

> 1st person singular (I, me, my)

> 1st person plural (we, us our)

> articles (a, an, the)

> emotion words (e.g., happy, sad, love, hate)

> cognitive words (e.g., because, reason, think, believe)

> social words (e.g., he, she, friend, cousin)

Most people assume that men use I-words and cognitive words more than women and that women use we-words, emotions, and social words more than men. Bad news. You were right if you guessed that women use social words more. However, women use I-words and cognitive words at far higher rates than men. There are no reliable differences between men and women for use of we-words or emotion words (OK, those were trick questions). And men use articles more than women, when you might guess there’d be no difference.

These differences hold up across written and spoken language and most other languages that we have studied. 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. 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.

Men and women use language differently because they negotiate their worlds differently. Across dozens and dozens of studies, women tend to talk more about other human beings. Men, on the other hand, are more interested in concrete objects and things. To talk about human relationships requires social and cognitive words. To talk about concrete objects, you need concrete nouns which typically demand the use of articles.

No matter what your sex, if you have to explain that Sally is leaving her husband because of her new lover, you have to make references to all the actors and you have to do some fairly complex cognitive analyses. If you have to explain why your carburetor in your car is broken, your causal analysis will likely be relatively pallid and will involve referring to concrete nouns.

COOK: You write about using this to analyze historical documents. Do you think this tool might be of any use to historians or biographers?

PENNEBAKER: Historians and biographers should jump on this new technology. The recent release of the Google Books Project should be required reading for everyone in the humanities. For the first time in the history of the world, there are methods by which to analyze tremendously large and complex written works by authors from all over the world going back centuries. We can begin to see how thinking, emotional expression, and social relations evolve as a function of world-wide events. The possibilities are breathtaking.

In my own work, we have analyzed the collected works of poets, playwrights, and novelists going back to the 1500s to see how their writing changed as they got older. We’ve compared the pronoun use of suicidal versus non-suicidal poets. Basically, poets who eventually commit suicide use I-words more than non-suicidal poets.

The analysis of language style can also serve as a psychological window into authors and their relationships. We have analyzed the poetry of Elizabeth Barrett and Robert Browning and compared it with the history of their marriage. Same thing with Ted Hughes and Sylvia Plath. Using a method we call Language Style Matching, we can isolate changes in the couples’ relationships.

COOK: What are some of the more unusual “texts” you have applied this technique to?

PENNEBAKER: Some of the more unusual texts have been my own. There is something almost creepy about analyzing your own emails, letters of recommendation, web pages, and natural conversations.

COOK: And what have you found?

PENNEBAKER: One of the most interesting results was part of a study my students and I conducted dealing with status in email correspondence. Basically, we discovered that in any interaction, the person with the higher status uses I-words less (yes, less) than people who are low in status. The effects were quite robust and, naturally, I wanted to test this on myself. I always assumed that I was a warm, egalitarian kind of guy who treated people pretty much the same.

I was the same as everyone else. When undergraduates wrote me, their emails were littered with I, me, and my. My response, although quite friendly, was remarkably detached -- hardly an I-word graced the page. And then I analyzed my emails to the dean of my college. My emails looked like an I-word salad; his emails back to me were practically I-word free.

COOK: Does your work have any application in lie detection?

PENNEBAKER: It does. Several labs, including ours, have now conducted studies to evaluate the prospect of building a linguistic lie detector. The preliminary findings are promising. In controlled studies, we can catch lying about 67% of the time where 50% is chance. Humans, reading the same transcripts, only catch lying 53% of the time. This is actually quite impressive unless you are a person in the judicial system. If you are waiting for a language-based system to catch real world lying at rates of 90 or 95 percent of the time, it won’t happen in your lifetime. It’s simply too complicated.

COOK: What are you looking into now? Where do you see the field going in the future?

PENNEBAKER: One of the most fascinating effects I’ve seen in quite awhile is that we can predict people’s college performance reasonably well by simply analyzing their college admissions essays. Across four years, we analyzed the admissions essays of 25,000 students and then tracked their grade point averages (GPAs). Higher GPAs were associated with admission essays that used high rates of nouns and low rates of verbs and pronouns. The effects were surprisingly strong and lasted across all years of college, no matter what the students’ major.

To me, the use of nouns -- especially concrete nouns -- reflects people’s attempts to categorize and name objects, events, and ideas in their worlds. The use of verbs and pronouns typically occur when people tell stories. Universities clearly reward categorizers rather than story tellers. If true, can we train young students to categorize more? Alternatively, are we relying too much on categorization strategies in American education?

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. It’s a wonderful time to be alive.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.