Toward an animal model of depression: a study of separation behavior in dogs

Six dogs were raised in an experimental setting by the author who was their sole consistent object. The animals were ranked daily in an approach-avoidance test and their temperament characterized in approach-avoidance terms. Eleven independent observers scored the animals on object seeking, object avoiding and aggressive behavior in each of three conditions (1) a pre-separation period in which the animals' relationship with the author was undisturbed (2) a separation condition in which the animals had no contact with the author and (3) a reunion period. Body weight and gross motor activity were also measured.Separation was associated with increases in object seeking for animals of the approach temperament and increases in object avoidance and aggressive behavior for animals of the avoidance temperament. Activity was significantly decreased in those animals for whom reliable data was obtained. Reunion was associated with further deviations from pre-separation behavior patterns. These results tentatively indicate that models of separation and depression can be constructed in experimental animals.