

You just revealed something about yourself in that statement. Here’s a simple, pronoun-heavy sentence: I don’t think I buy it. When we analyze people’s use of function words, we can get a sense of their emotional state and personality, and their age and social class. They are the key to understanding relationships between speakers, objects, and other people. People require social skills to use and understand function words, and they’re processed in the brain differently. Function words help shape and shortcut language. Content words-nouns, verbs, adjectives, and most adverbs-convey the guts of communication. In English there are about 500 function words, and about 150 are really common. HBR: Why are function words so important? When we analyzed military transcripts, we could tell people’s relative ranks based on their speech patterns-and again, it was the pronouns, articles, conjunctions, and other function words that made a difference, not the content words.

We didn’t-but we did discover significant differences in the frequency of words like “I.” In study after study, we kept finding the same thing. For instance, when we analyzed poems by writers who committed suicide versus poems by those who didn’t, we thought we’d find more dark and negative content words in the suicides’ poetry. Pennebaker: When we began analyzing people’s writing and speech, we didn’t expect results like this. The challenge: Can insignificant words really provide a “window to the soul”? Professor Pennebaker, defend your research. After analyzing 400,000 texts-including essays by college students, instant messages between lovers, chat room discussions, and press conference transcripts-he concluded that function words are important keys to someone’s psychological state and reveal much more than content words do. The research: In the 1990s, James Pennebaker helped develop a computer program that counted and categorized words in texts, differentiating content words, which convey meaning, from function words. The finding: A person’s use of function words-the pronouns, articles, prepositions, conjunctions, and auxiliary verbs that are the connective tissue of language-offers deep insights into his or her honesty, stability, and sense of self.
