In dreams, could we discover where the mysterious feeling of revelation comes from?

In "Too Hard for Science?" I interview scientists about ideas they would love to explore that they don't think could be investigated. For instance, they might involve machines beyond the realm of possibility, such as particle accelerators as big as the sun, or they might be completely unethical, such as lethal experiments involving people. This feature aims to look at the impossible dreams, the seemingly intractable problems in science. However, the question mark at the end of "Too Hard for Science?" suggests that nothing might be impossible.

The scientist: Robert Stickgold, director of the Center for Sleep and Cognition at Harvard Medical School.

The idea: Dreams often feel profoundly meaningful, bizarre experiences often interpreted over the centuries as messages from the gods or as windows into the unconscious. However, maybe our brains are just randomly stringing experiences together during sleep and investing the result with a feeling of profundity.

"When people learn about what I do, they often tell me about their dreams without me asking, and I can't tell you how many times people told me they had the most amazing dreams, and they're almost never amazing — they're almost always somehow embarrassingly uninteresting," Stickgold says. "But this happens to me, too."

By investigating why dreams feel profound, one might learn how events get imbued with this sense of meaning — perhaps the same one felt during revelations. Stickgold notes that during REM sleep, when dreaming typically occurs, the release of the neurotransmitter serotonin is shut off in the brain. The only other time that happens is because of LSD, "when people seem to have these totally uninteresting experiences they describe as profoundly meaningful called 'acid insights.'"

This sense of meaning may be a physical phenomenon "just like hunger or thirst, save that it's the excitement we feel upon a great insight, that 'Aha!' feeling," Stickgold says. "Who knows why, for instance, fireworks often seem to trigger it — maybe there's something about the geometric patterns that evokes this sense of awesomeness, the feeling that we can almost understand something amazing but not quite that drives us to seek a better understanding of things. It's like what you feel during a religious experience — you sense the oneness of mankind."

During dreams, the brain might be associating disjointed experiences together to create potentially valuable combinations of thoughts. "It could be the brain is making you focus your attention on material that was only weakly associated before and investing this association with this feeling of profundity to help it mine these connections for something not immediately obvious but potentially important," Stickgold says. "It makes sense that the sensation would be a positive and reinforcing one."

The problem: The difficulty in exploring this idea is that how meaningful something is might be too hard to measure. "It's a bit like beauty — it's in the mind of the beholder," Stickgold says. "It's not like heart rate or the level of electrical conductivity of the skin, which you have outside evidence of. If a person says something is meaningful, you're not sure how to measure that, and you're not sure how, if at all, that applies to others. One has to come up with a meaningful definition of meaningful."

The solution? Experiments with drugs that suppress or boost serotonin levels could explore any connections between the neurotransmitter and the feeling of meaning. "You could give people such compounds or a placebo and get them to rate how deep or meaningful specific movie clips seems to them," Stickgold suggests.

Although dreaming most frequently occurs in REM sleep, it also occurs in non-REM sleep. Researchers could ask people if dreams during non-REM sleep, when serotonin levels aren't suppressed, "feel as intense and bizarre and emotional as ones during REM sleep," Stickgold says. One might also try giving serotonin-influencing drugs to people as they sleep and dream, he adds.

"It's clear that there is a useful scientific question here," Stickgold notes. "What is it about the dream process that so frequently and universally across people generates this very strong perception of something like importance or significance or deepness, a feeling we find hard to define, and one that's often totally wrong, in that when you tell others about your dreams, you find they don't have any obvious significance? It's just a matter of clarifying what the question really is, and then finding a good way of exploring it."


This idea from Stickgold, which I first heard when he was speaking at a preview screening of Satoshi Kon's anime Paprika, was what inspired me to come up with this series in the first place. It seemed like an amazing concept worth reporting, but one that couldn't fit into the confines of a traditional news story as there seemed no way to actually investigate it. Eventually, it occurred to me, "He can't possibly be alone." One impossible dream might not be reportable, but a thousand might be.

The first item in this series, which appeared last week, was the first such notion I can remember running across as a journalist. I originally included it in my first story on bio-printing, but it was removed for essentially being too radical to run. Just the kind of concept this series hopes to explore.

Another piece in this series will run later this week, featuring the first scientist to respond to my open request for ideas that might be too hard for science. If you have a scientist you would like to recommend I question, or you are a scientist with an idea you think might be too hard for science, email me at

Follow Too Hard for Science? on Twitter by keeping track of the #2hard4sci hashtag.

About the Author: Charles Q. Choi is a frequent contributor to Scientific American. His work has also appeared in The New York Times, Science, Nature, Wired, and LiveScience, among others. In his spare time he has traveled to all seven continents. Follow him on Twitter @cqchoi.

The views expressed are those of the author and are not necessarily those of Scientific American.