Over a half a century ago, Alex Osborne wrote an influential book called Applied Imagination that opined that "the average person can think up twice as many ideas when working with a group than when working alone." Managers must have been convinced because brainstorming groups took off in popularity and are still used widely to this day. In fact, in business schools it is almost heretical to argue that teams are not more creative than individuals.

The only problem is that Osborne was wrong. Dozens of laboratory studies tried to confirm Osborne's claim, but found the opposite: brainstorming groups produced fewer ideas, and ideas of less novelty, than the sum of the ideas created by the same number of individuals working alone.

How could this be? Aren't ideas supposed to cross-fertilize, coming up with new and unusual hybrids through a process sometimes referred to as idea sex? It turns out group idea sex is of the ho-hum variety; more exciting ideas come from going solo.

There are three main reasons that groups are less creative than individuals working on their own:

1. Fear of Judgment

A series of studies by Professors Michael Diehl, Wolfgang Stroebe, Bernard Nijstad, Paul Pauhus, and others found that people self-censor many of their most creative ideas in group brainstorming sessions for fear of being judged negatively by others. When the scientists told groups that their ideas would be judged by their peers, they came up with significantly fewer and less novel ideas than groups that were told they would be evaluated by anonymous judges.

As Isaac Asimov, one of the most famous science fiction writers of all time (and also a biochemistry professor at Boston University) put it, "My feeling is that as far as creativity is concerned, isolation is required...The presence of others can only inhibit this process, since creation is embarrassing. For every new good idea you have, there are a hundred, ten thousand foolish ones, which you naturally do not care to display."

2. Production Blocking

When people take turns to voice their ideas, those bringing up the rear may forget their ideas before having a chance to voice them. Worse still, the process of attending to another person's ideas redirects a listener's train of thought, essentially hijacking their own idea generation process. Scientists were able to demonstrate this by separating individuals into rooms where they would speak their ideas into a microphone when lights indicated it was their turn. In some of the rooms the individuals could hear the contributions of others, and in some they could not. This study resulted in big creativity losses: being required to wait to give ideas caused people to submit far fewer ideas, and even fewer ideas if they could hear the contributions of others.

Now imagine what happens when people do not have to take turns but instead volunteer ideas at will: the most outgoing people in the group will dominate the idea submission while the quieter people, or those more worried about social pressure, do not submit many (or any) of their ideas. Furthermore, if they do submit their ideas, they may submit only those ideas that build upon the ideas that were already contributed - a sure way to drive out novelty.

3. Feasibility Trumps Originality

Another series of studies by Professor Eric Rietzschel and colleagues shows that teams aren't just bad for idea generation; they even impair idea selection. If you let people work alone to generate ideas but then let the group select the best ideas to pursue, they will make decisions that reduce novelty. The studies showed that when groups interactively ranked their "best" ideas, they chose ideas that were less original than the average of the ideas produced, and more feasible than the average of the ideas produced. In other words, people tended to weight "feasible" more highly than "original." If a brainstorming group is intended to elicit novel ideas, asking groups to select and submit their best ideas is not the way to achieve that outcome.

The Benefits of Spending Time Alone

Solitude is immensely valuable for creativity; it affords a person the time to think and pursue those things they find intrinsically interesting. It can help them to develop their own beliefs about how the world works, and to develop a self-concept that is less structured by the opinions of others.

In my research on serial breakthrough innovators, I found that all of the innovators had spent significant time alone, pursuing their own interests. Most were voracious readers --Elon Musk, for example, often read for 10 hours a day, and his brother Kimbal noted "If it was the weekend he could go through two books in a day." Elon Musk himself says, "I was raised by books. Books and then my parents."

Many of the innovators were also "autodidacts," vastly preferring to teach themselves subjects rather than being taught in school. This helped them to become independent thinkers that challenged assumptions. Thomas Edison noted about himself, for example, that he found he "involuntarily challenged" everything he read and desired to demonstrate whether it was right or wrong. His individualistic style of acquiring knowledge and his reflexive challenging of received wisdom eventually led him to question many of the prevailing theories of electricity. And of the innovators I studied, Albert Einstein was most vocal about the need for solitude and individuality in creativity, arguing, "The really valuable thing in the pageant of human life seems to me not the political state, but the creative, sentient individual, the personality; it alone creates the noble and the sublime, while the herd as such remains dull in thought and dull in feeling."

When managers want employees to come up with breakthroughs, they need to give people some time alone to ponder their craziest of ideas and follow their paths of association into unknown terrain. They should be urged to come up with ideas freely, without fear of judgment. They should be encouraged to commit their ideas to paper, and to flesh each of them out before exposing them to others. Managers can also follow Google and 3M's lead and give employees in creative roles a significant percentage of their time (e.g., 3M uses 15% of work hours) where they pursue products of their own creation and choosing. Google's Gmail and Google News, and 3M's Post-it-Notes, and many other products, were developed this way.