 Tryon then mated the “bright” males with “bright” females, and “dull” males with “dull” females.After their children matured, Tryon repeated the maze test with them, and again separated the “bright” and the “dull”, again breeding “bright” with “bright” and “dull” with “dull”.Tryon continued this process for seven generations, creating two distinct breeds of “bright” and “dull” rats.