Dog-Noise (DN) – non-informative sound: presentation of Brownian noise with projections of dog pictures. This control was conducted to test if there was any effect caused by the size difference of the dog pictures on the looking behavior of the subjects. (N = 24)
Shape-Growl (SG) – non-informative picture: presentation of dog growls with projection of triangles. This control group was used to test if the looking preferences of the dogs were nonspecific in that they would occur also with non-natural, unknown pictures. (N = 24)
Cat-growl (CG) – non-matching modalities: presentation of dog growls with projection of cat pictures. This control was conducted to test the effect of the nature of the pictures. (N = 24)