Two Harvard psychologists have authored a study showing that suppressed thoughts manifest themselves in dreams —the first scientific confirmation of Sigmund Freud’s theory of dreams.

The study, which will appear in the March issue of Psychological Science, was authored by Professor of Psychology Daniel M. Wegner and fourth-year graduate student Megan N. Kozak, along with Richard M. Wenzlaff of the University of Texas at San Antonio.

Wegner, Kozak and Wenzlaff were motivated by Freud’s theory that dreams drew upon man’s hidden thoughts and decided to study the relation between the content of dreams and people’s waking lives.

They found that things that people worry about often appear in their sleeping hours.

“When we try not to think about something, it often rebounds with greater frequency in our dreams,” Kozak said. “Our study focuses on this phenomenon and it is a crossroads between mental control and looking at what happens when we dream.”

The experiment involved 330 students from the University of Texas at San Antonio who were taking either a first-year or sophomore introductory psychology class.

Kozak said that the experiment was unique because it did not take place in a laboratory setting.

The subjects were given booklets in which to write for five minutes before going to bed, allowing them to sleep comfortably and dream as they normally would in a familiar environment.

The students were asked to either write down something about a person they knew, something of their own free choice, or to write freely about anything while suppressing thoughts about a person that they knew.

As soon as they awoke the next morning, the subjects were asked to write down the content of their dreams in their individual dream diaries. The researchers went through the journals and counted the number of times the subjects mentioned the person or object that they wrote about before falling asleep.

The study found that people generally dreamt about what they wrote in the booklets before going to bed.

Wegner said the effect was most pronounced in people who were asked to suppress their thoughts.

“Suppression increases the amount of dreaming about the target person more than does thinking about the person,” Wegner said.

Wegner said that their results indicate that dreams aren’t as complex as we think they are.

“There are lots of theories on what dreams are for or what dreams represent,” Wegner said. “Our studies suggest that dreams may not be for anything at all. They just reflect what we try to suppress when we are awake.”

Another surprising result of the study was that the students did not dream more frequently about people to whom they have an emotional attachment.

Whether a potential subject was a close friend or a casual acquaintance had no bearing on how often he or she appeared in the students’ dreams.

“The students were just as likely to dream about a crush as they were about a normal person. The emotional attachment made no difference in how often they appeared in the dreams. Suppression was the only main difference,” Wegner said.

Wegner said that this finding on emotion differentiates the study’s results from Freud’s. While the study claims that dreams reflect people’s suppressed thoughts but do not depend on an emotional connection, Freud claimed that emotional connections were an important factor in interpreting dreams.

But like Freud’s psychoanalysis, these findings may have some interesting therapeutic applications.

Wegner said that since people who suffer from stress or depression often tend to have nightmares, the contents of dreams may then help to determine the problems that a person encounters during the day.

“Dreams reflect what people try not to think about. It would be interesting to see if bad dreams would occur less if people allowed themselves to think about negative topics rather than suppressing them,” Kozak said.

Professor of Psychology Daniel T. Gilbert said that the scientific community has favorably received the study, viewing it as an important step in understanding the functioning of the human mind.

Gilbert described Wegner’s research as an “elegant and potentially important study that extends his groundbreaking research on the consequences of thought suppression and mental control into the world of dreams.”