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.
No one, that is, before two different research teams—Clarke Burnham with Kenneth Davis, and Joseph Alba with Robert Weisberg—ran another experiment using the same puzzle but a different research procedure.
Both teams followed the same protocol of dividing participants into two groups.
your conclusion: that the second experiment disproves the theory that thinking outside the box is useful in solving problems, is itself a fallacy.
it only proved that telling someone to 'think out side the box' is, in most cases, ineffective.
Yet participants’ performance was not improved even when they were given specific instructions to do so.