Only 20 percent managed to break out of the illusory confinement and continue their lines in the white space surrounding the dots.

The symmetry, the beautiful simplicity of the solution, and the fact that 80 percent of the participants were effectively blinded by the boundaries of the square led Guilford and the readers of his books to leap to the sweeping conclusion that creativity requires you to go outside the box.

Speakers, trainers, training program developers, organizational consultants, and university professors all had much to say about the vast benefits of outside-the-box thinking.

Guilford was one of the first academic researchers who dared to conduct a study of creativity.

He challenged research subjects to connect all nine dots using just four straight lines without lifting their pencils from the page.

Both teams followed the same protocol of dividing participants into two groups.

The first group was given the same instructions as the participants in Guilford’s experiment.

That is, direct and explicit instructions to think outside the box did not help.

That this advice is useless when actually trying to solve a problem involving a real box should effectively have killed off the much widely disseminated—and therefore, much more dangerous—metaphor that out-of-the-box thinking spurs creativity.

Solving this problem requires people to literally think outside the box.

Yet participants’ performance was not improved even when they were given specific instructions to do so.

The second group was told that the solution required the lines to be drawn outside the imaginary box bordering the dot array.