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.
Rather than disproving the myth, in other words, the experiment might instead offer evidence that creativity is an ability that one is born with, or born lacking, hence why information from the environment didn't impact the results at all.
The first group was given the same instructions as the participants in Guilford’s experiment.
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.