 Rather, it has become a widely accepted belief among behavior geneticists that the superiority of the bright rats was confined to Tryon’s specific test; thus, it is not possible to claim that there is a difference in learning capacity between the two groups of rats.Genetic variation, such as better peripheral vision, can make some rats “bright” and others “dull”, but does not determine their intelligence.Nonetheless, Tryon’s famous rat-maze experiment demonstrated that the difference between rat performances was genetic since their environments were controlled and identical.