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.
The second group was told that the solution required the lines to be drawn outside the imaginary box bordering the dot array.
Although studying creativity is considered a legitimate scientific discipline nowadays, it is still a very young one. One of Guilford’s most famous studies was the nine-dot puzzle.
Guilford was one of the first academic researchers who dared to conduct a study of creativity.
The correct solution, however, requires you to draw lines that extend beyond the area defined by the dots.
At the first stages, all the participants in Guilford’s original study censored their own thinking by limiting the possible solutions to those within the imaginary square (even those who eventually solved the puzzle).