In the controlled behavior test, puppies were presented with a series of controlled stimuli and their reactions were scored by a member of Guide Dogs staff on a seven point scale according to behavioral descriptors. These tests took place from May to October 2012. The later outcome of dogs (withdrawal or qualification and movements between stages) was accessed from Guide Dogs records in October 2014, but these decisions were made independently of scores on the PPA. Scores of the PPA have previously been found to be associated with qualification as a guide dog, supporting the predictive criterion validity of the test (17). Some scores on the PPA are also heritable (18) and Guide Dogs use this test routinely to record behavior of puppies. In the PPA, puppies are scored according to their response or recovery to stimuli and the human assessor. Full details can be found in Asher et al. (17), but in brief, the stimuli the puppies encounter are: “Following” where they are encouraged to follow a person, a toy, which they are encouraged to “Retrieve,” a brief and gentle “Restraint,” playback of aircraft “Noise,” “Stroking” by a person, a small furry object moved fast on a string to mimic a “Squirrel”-like prey, a “Tunnel,” which they are encouraged to move through, and a “Ramp,” which they are encouraged to walk over.