The first group was given the same instructions as the participants in Guilford’s experiment.
It was an appealing and apparently convincing message.
Indeed, the concept enjoyed such strong popularity and intuitive appeal that no one bothered to check the facts.
Even though they weren’t instructed to restrain themselves from considering such a solution, they were unable to “see” the white space beyond the square’s boundaries.
Only 20 percent managed to break out of the illusory confinement and continue their lines in the white space surrounding the dots.
He challenged research subjects to connect all nine dots using just four straight lines without lifting their pencils from the page.