Aggression in the domestic dog – Part 2


The test areas
The studies were performed in the facilities for dog research at Utrecht University. The sub-tests in the final test were done mainly indoors (Fig. 1). From the pilot studies, we concluded that it was easier to control the stimulus situation and build up a certain tension during a test when it was done indoors. Dogs could move around freely in area a during some of the sub-tests. Test persons were never allowed in that area when the dogs were moving freely. During most sub-tests the dogs were constrained in area b or c (see Fig. 1). The leash(es) could be attached to a very strong hook on the wall in the middle of area b or area c. An extra rope was added to secure very heavy and strong dogs. On the floor of both areas, a line was painted for security reasons. The test-person was given direct information about how close he or she could safely come to the dog. Next to area b, there were two chairs for the owner, the one closer to the dog being slightly more than an arm’s length from the dog so that the owner could not pet the dog. The second chair, placed at an extra arm’s length from the dog, was used for safety reasons when the owner was interacting with a stimulus dog. The owner was asked to bring along the basket/bed in which the dog normally lay/slept. This was placed in the centre of area b against the wall. This gave the dog a chance to retreat and could perhaps play a role in territorial defence. A few sub-tests were done out of doors for practical reasons. The outdoor testing facilities were adjacent to the test-room. Dogs were given a leather collar and a leather leash before testing: big dogs got two of both for security reasons. The sub-tests simulated situations in which aggression may occur. Some non-threatening sub-tests were performed in the first part of the test in order to ” acclimatise ” the owner and the dog.


Description of the sub-tests
References between brackets in the description of the sub-tests refer to the literature in which the sub-test or a variation of the sub-test or the aggressive context involved is mentioned. The codes indicating the positions of the dog in the test-room refer to Fig. 1.
Sub-tests 1-6

  • 1) Two test-persons approach the dog-owner’s car containing the dog and one of these persons stares at the dog; one of the test-persons knocks on the car window and rattles the door (van der Borg et al., 1991).
  • 2) The owner walks the dog up and down on the leash outdoors, for a distance of 20m.
  • 3) The owner gives the command ” sit’ ; the owner keeps the dog in a sitting position for 20s if necessary with the assistance of means such as the leash (O’Farrell, 1986; Voith, 1982).
  • 4) The owner gives the command ” down” ; the owner keeps the dog in this position for 20 s, if necessary with the assistance of means such as the leash (O’Farrell, 1986; Voith, 1982).
  • 5) Confrontation with three free-running barking stimulus (not dominant) bitches behind a fence (length 20m); the owner walks with the dog on the leash once along the fence and back again at a distance of 1 m from the fence.
  • 6) Confrontation of the dog (in the absence of the owner) with a barking dominant male stimulus dog behind a fence in the absence of the owner; the test dog is 1 m from the fence tied with a 1.5 m leash to a grapple in the ground. After this sub-test the dog is transferred to the adjacent test room (Fig. 1, using doors 1 and 2), where all the other sub-tests are carried out. Door 6 can be closed to conceal observers and test-persons. Test-persons enter the test room using doors 2 and 3 and stimulus dogs enter by door 2.

Sub-tests 7-9: dog moves freely in area a; pefotmed in presence of owner
  • 7) The owner gives the command “come”.
  • 8) The owner plays with his/her dog for 1 min using a familiar toy.
  • 9) The owner plays tug-of-war with his/her dog for 1 min using an unfamiliar toy (specially chosen for its suitability for use in a game of tug-of-war) (O’Farrell, 1986; van der Wijk and Klasen, 1981).

Sub-tests 10-19: dog in area b; performed in presence of owner
For sub-tests lo-12 and 16-19 the owner is sitting in the chair next to the dog (Fig. 1).
  • 10) A test-person shines a small electric torch into the eyes of the dog and looks into its eyes (dog in area b; the owner holds the dog’s head): this is a test to check whether the dog has been given sedatives.
  • 11) A test-person plays tug-of-war with the dog using the same toy as in test 9 (Beck et al., 1975; van der Wijk and Klasen, 1981).
  • 12) A test-person pets the dog using an artificial hand; the artificial hand is a very natural-looking model of a hand that is made of a strong/tough type of plastic material; the artificial hand can be operated by a stick attached to the artificial hand; the stick is covered with a sleeve to hide the hand of the test-person operating the artificial hand (O’Farrell, 1986; Mugford and Gupta, 1984; van der Wijk and Klasen, 1981).
  • 13) The owner stares at the dog.
  • 14) The owner holds the dog’s muzzle with two hands.
  • 15) The owner pushes the dog over on its back and tries to hold it in this position with one hand or two hands placed on the dog’s breast.
  • 16) The owner squeezes the skin on one of the dog’s groins rather tightly.
  • 17) Using the artificial hand, a test-person pulls away the dog’s feeding bowl filled with the dog’s favourite food type or a commercial brand of dry dog food (van der Borg et al., 1991).
  • 18) Using the artificial hand, the owner pulls away the dog’s feeding bowl filled with commercial brand of dry dog food.
  • 19) A test-person walks towards the owner and shakes hands vigorously with him/her and speaks loudly in a mildly threatening way (Beck et al., 1975).

Sub-tests 20-28: dog in area b; pe$onned in the absence of the owner.
  • 20) A test-person uses a rattle at the edge of area b in front of the dog.
  • 21) A test-person suddenly opens an umbrella with an automatic opening device at the edge of area b in front of the dog.
  • 22) A test-person drags in a big (diameter OSOm) plastic bag filled with foam chips which makes a peculiar noise as it is dragged along the edge of area b in front of the dog.
  • 23) A test-person dressed as a strange-looking woman, walking with a stick, approaches the dog, tries to pet the dog using the artificial hand and speaks in a strange high piercing voice (Winkler, 1977).
  • 24) A life-sized doll (little girl) 65 cm tall, standing on a board mounted on small wheels, is pulled at walking speed towards the dog by a test-person who is out of the dog’s sight (Blackshaw, 1988; Wright, 1985; van der Borg et al., 1991).
  • 25) A test-person holds the doll and tries to touch the dog with the doll’s hand (if the dog does not retreat).
  • 26) A test-person stares at the dog (Mugford and Gupta, 1984; Winkler, 1977).
  • 27) A test-person claps his/her hands loudly in front of the dog.
  • 28) A test-person threatens the dog by yelling and shouting and making hitting and kicking movements in the direction of the dog just out of reach of the dog (Wright, 1985).

Sub-tests 29-43: performed in the presence of the owner.
  • 29) A model of a human male (1.90 m; normally dressed, wearing a hat; the model can rotate at knee level) lying on its back in stretched position is pulled up to a standing position the moment the owner with the dog on the leash comes through the door (Fig. 1, dog and owner leave the test room by door 4 and enter by door 5) directly in front of the model. For sub-tests 30-34 the dog is in area c, with the owner standing next to the dog and holding the leash:
  • 30) Three persons approach the dog slowly step by step and surround the dog; the owner is standing next to the dog.
  • 31) In the same situation as in sub-test 30, three persons approach and surround the dog very rapidly.
  • 32) The dog is threatened by a test-person with a broom; the test-person yells and screams banging the broom on the floor in front of the dog just inside area c; if the dog bites the broom the test continues.
  • 33) A test-person threatens the owner by yelling and shouting at him/her and that test-person pushes the owner with the artificial hand (Beck et al., 1975; Seiferle and Leonhardt, 1984).
  • 34) Dog and owner are cornered by two persons with three barking dogs on the leash; one of the dogs is a dominant male, two dogs are submissive males; the dogs are stimulated to bark; the stimulus dogs are allowed to come within OSOm of area c. For sub-tests 35-43, the dog is in area b with the owner sitting in the chair next to the dog; in sub-tests 36 and 40, to prevent accidents, the owner is in the chair that is further away.
  • 35) A test-person with an unknown dominant male dog on the leash approaches the dog, stopping at a distance of 0.50m from the edge of area b (Goddard and Beilharz, 1985).
  • 36) A test-person walks with the dominant male dog towards the owner and the owner is asked to pet the stimulus dog and not to pay any attention to his/her dog (Goddard and Beilharz, 1985).
  • 37) The dog is given his feeding bowl by his owner in area b at a distance of 0.50m from the dominant male dog (Goddard and Beilharz, 1985).
  • 38) The owner gives his dog’s feeding bowl to the dominant male dog at a distance of 0.50m from the edge of area b (Goddard and Beilharz, 1985).
  • Sub-tests 39-42: these sub-tests are the same as tests 35-38, but they are performed with an unknown moderately dominant female stimulus dog; if the test dog is a male dog sub-tests 39-42 are performed before sub-tests 35-38.
  • 43) The owner puts the dog in a lying position in his own basket/bed in area b; a test-person approaches the dog in area b and pets the dog using the artificial hand.