Most people assume that 60 percent to 90 percent of the group given the clue would solve the puzzle easily. What’s more, in statistical terms, this 5 percent improvement over the subjects of Guilford’s original study is insignificant.
In other words, the difference could easily be due to what statisticians call sampling error.
It's an interesting experiment, but the author's conclusion cannot possibly follow from the results of it.
your conclusion: that the second experiment disproves the theory that thinking outside the box is useful in solving problems, is itself a fallacy.
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.
He challenged research subjects to connect all nine dots using just four straight lines without lifting their pencils from the page.
Today many people are familiar with this puzzle and its solution.
Because the solution is, in hindsight, deceptively simple, clients tended to admit they should have thought of it themselves.
Because they hadn’t, they were obviously not as creative or smart as they had previously thought, and needed to call in creative experts. The nine-dot puzzle and the phrase “thinking outside the box” became metaphors for creativity and spread like wildfire in marketing, management, psychology, the creative arts, engineering, and personal improvement circles.