Unwanted Thoughts

Trying hard not to think about an old love? Don't be
surprised if he stampedes through your dreams like the proverbial
elephant. When subjects were told to avoid thinking about a certain
someone before falling asleep, they were more likely to dream of that
person than subjects asked to purposefully keep someone in mind. And,
whereas Freud believed only desirable targets would assert themselves in
dreams, subjects dreamed just as often of people to whom they were not
attracted as they did of attractive targets.

"Things we sweep under the rug fill our minds while we
dream," says Daniel Wegner, lead researcher and professor of
psychology at Harvard University, which
explains why smokers trying to quit, for example, tend to dream about
lighting up. The study pokes holes in a popular theory that says dreaming
is the brain's way of interpreting random activations. "This
proves that some dreams are not random; they do come from prior
content—particularly content you're trying to block
out," he says.

Wegner describes the phenomenon in terms of two mental
processes—one keeps the brain on task, while an opposing
"ironic" system scouts out the very thoughts we are
consciously trying to keep at bay. "While we sleep, the system
engaged in mental control is not very operative," Wegner says,
which leaves the ironic system free to take over, and release unwanted
thoughts into the wild.