 While the olfactory bulb/peduncle was activated to a similar degree by all the scents, the caudate was activated maximally to the familiar human.Importantly, the scent of the familiar human was not the handler, meaning that the caudate response differentiated the scent in the absence of the person being present.The caudate activation suggested that not only did the dogs discriminate that scent from the others, they had a positive association with it.