You probably don’t think about how often you say the word “I.”

You should. Researchers say that your usage of the pronoun says more about you than you may realize.

Surprising new research from the University of Texas suggests that people who often say “I” are less powerful and less sure of themselves than those who limit their use of the word. Frequent “I” users subconsciously believe they are subordinate to the person to whom they are talking.

Pronouns, in general, tell us a lot about what people are paying attention to, says James W. Pennebaker, chair of the psychology department at the University of Texas at Austin and an author on the study. Pronouns signal where someone’s internal focus is pointing, says Dr. Pennebaker, who has pioneered this line of research. Often, people using “I” are being self-reflective. But they may also be self-conscious or insecure, in physical or emotional pain, or simply trying to please.

Dr. Pennebaker and colleagues conducted five studies of the way relative rank is revealed by the use of pronouns. The research was published last month in the Journal of Language and Social Psychology. In each experiment, people deemed to have higher status used “I” less.

The findings go against the common belief that people who say “I” a lot are full of themselves, maybe even narcissists.

“I” is more powerful than you may realize. It drives perceptions in a conversation so much so that marriage therapists have long held that people should use “I” instead of “you” during a confrontation with a partner or when discussing something emotional. (“I feel unheard.” Not: “You never listen.”) The word “I” is considered less accusatory.

“There is a misconception that people who are confident, have power, have high-status tend to use ‘I’ more than people who are low status,” says Dr. Pennebaker, author of “The Secret Life of Pronouns.” “That is completely wrong. The high-status person is looking out at the world and the low-status person is looking at himself.”

So, how often should you use “I”? More—to sound humble (and not critical when speaking to your spouse)? Or less—to come across as more assured and authoritative?

The answer is “mostly more,” says Dr. Pennebaker. (Although he does say you should try and say it at the same rate as your spouse or partner, to keep the power balance in the relationship.)

In the first language-analysis study Dr. Pennebaker led, business-school students were divided into 41 four-person, mixed-sex groups and asked to work as a team to improve customer service for a fictitious company. One person in each group was randomly assigned to be the leader. The result: The leaders used “I” in 4.5% of their words. Non-leaders used the word 5.6%. (The leaders also used “we” more than followers did.)

In the second study, 112 psychology students were assigned to same-sex groups of two. The pairs worked to solve a series of complex problems. All interaction took place online. No one was assigned to a leadership role, but participants were asked at the end of the experiment who they thought had power and status. Researchers found that the higher the person’s perceived power, the less he or she used “I.”

In study three, 50 pairs of people chatted informally face-to-face, asking questions to get to know one another, as if at a cocktail party. When asked which person had more status or power, they tended to agree—and that person had used “I” less.

Study four looked at emails. Nine people turned over their incoming and outgoing emails with about 15 other people. They rated how much status they had in relation to each correspondent. In each exchange, the person with the higher status used “I” less.

The fifth study was the most unusual. Researchers looked at email communication that the U.S. government had collected (and translated) from the Iraqi military, made public for a period of time as the Iraqi Perspectives Project. They randomly selected 40 correspondences. In each case, the person with higher military rank used “I” less.

People curb their use of “I” subconsciously, Dr. Pennebaker says. “If I am the high-status person, I am thinking of what you need to do. If I am the low-status person, I am more humble and am thinking, ‘I should be doing this.’ “

Dr. Pennebaker has found heavy “I” users across many people: Women (who are typically more reflective than men), people who are more at ease with personal topics, younger people, caring people as well as anxious and depressed people. (Surprisingly, he says, narcissists do not use “I” more than others, according to a meta-analysis of a large number of studies.)

And who avoids using “I,” other than the high-powered? People who are hiding the truth. Avoiding the first-person pronoun is distancing.

Researchers analyzed the language on Twitter of Boston bombing suspect Dzhokhar Tsarnaev. Mr. Tsarnaev used “I” words (I, me, my, I’ll, I’m, etc.) less and less in his tweets as he got closer to the bombing, according to not-yet-published research by Brittany Norman at Midwestern State University in Wichita Falls, Texas, and Dr. Pennebaker.

The researchers analyzed all 856 of Mr. Tsarnaev’s original tweets between October 2011 and April 15, 2013, the day of the bombing. They found that Mr. Tsarnaev’s use of “I” words dropped significantly as the bombing approached, with the biggest drop appearing in October 2012 (to 4.81% of his words from 9.57% the month before).

“The data suggest that Mr. Tsarnaev made the decision to do something that he had to hide at that time,” Ms. Norman says.

All his work leads Dr. Pennebaker to conclude: “You should use ‘I’ the same way you use a speedometer on your car—as feedback on yourself,” he says. “Are you being genuine? Are you being honest? Learn to adjust some, to know yourself.”

–Write to Elizabeth Bernstein at Bonds@wsj.com or follow her column at www.Facebook.com/EBernsteinWSJ or www.Twitter.com/EBernsteinWSJ