Video Supplement to Operants Magazine

The Benefits of Considering Degrees of Freedom in the Zoo Animal Community

By Barbara Heidenreich and T.V. "Joe" Layng, Ph.D.  

 Get Access to the Entire Article Visit: The BF Skinner Foundation to Subscribe to Operants Magazine  Or Visit: Research Gate

Zero Degrees of Freedom

Although described as having a “choice” to participate, opting out does not result in the same reinforcing consequences. Fallout from zero degrees of freedom includes undesired emotional behavior often labeled by animal trainers as conflicted, hesitant, or stubborn, which results from competing contingencies. An example of this hesitancy was observed when a Red-vented cockatoo (Cacatua haematuropygia) was trained to touch the tip of a dosing syringe with its beak. The bird avoided the syringe. However, touching the syringe was required to access desired food items. More preferred food items were utilized to increase responses. Although the bird participated in the session, the collateral (emotional) behavior was undesired.

We have found that such disturbing behavior is unlikely to occur if more degrees of freedom are incorporated into the training procedure. Further, it has the potential outcome of providing genuine choice, a means to assessing assent, and can add insights into intervention success.

Looking for Degrees of Freedom

Degrees of freedom can be found when evaluating the behavioral responses of a herd of Scimitar-horned Oryx (Oryx dammah) to a board placed in their space for them to stand upon to collect weights. The space contained plastic tubs filled with grain for the Oryx to eat at their convenience. One tub was placed at the end of the green weigh board. Food was also placed on the weigh board. One animal immediately engaged with the board when placed in the space. He pawed at it with his hooves and stood on it. Several walked across it, ate food from the tub at the end of the board, sniffed, and then bypassed the food on the board. No barriers or chutes coerced this action, and many other grain tubs were available. The animals could also access the tub of grain at the end of the weigh board from the opposite side, which would not require standing on the weigh board. The degrees of freedom were many, yet several animals still opted to stand on the weigh board. Observing this opened the door to questions about what else might be reinforcing about the board and situation. It was noticed the board had a different texture and smell and was novel. These observations inspired discussions on how the team could use this information to improve the procedures for training Oryx by including degrees of freedom and nonlinear contingency analysis (see the book by that name by Layng, et al.) as part of their tactics.

Degrees of Freedom Can Address Undesired Emotional Behavior

In the past, to feed two miniature donkeys (Equus asinus domestic) and a domestic cow (Bos taurus), animal caregivers would carry a bag of orchard grass and grain to the center of the yard and empty the contents into a single feeder. As caregivers tried to enter the gate, the two donkeys vocalized, bit, and kicked toward each other in what might be described as competition over the food. The situation was unsafe for the animals and the caregiver. Three feeding stations were created to address this problem, one for each animal. Reinforcement history was built for remaining at their individual stations for a duration; however, they could leave at any time if desired. While the animals remained at their stations, orchard grass, and grain were placed at several locations in the yard. This resulted in six separate locations the animals could walk to and obtain the same food items. The undesired responses of vocalizing, biting, and kicking were no longer emitted. The animals no longer needed to engage in costly behaviors of biting and kicking to get reinforcing outcomes now that they had more degrees of freedom. Building reinforcement history for desired responses and increasing the degrees of freedom has made daily management safer for humans and animals.

Degrees of Freedom Provide Information

Shaping behavior with positive reinforcement and increased degrees of freedom can reveal essential information. A standard behavior goal for cooperation in medical care is to train animals to press their side against the perimeter barrier or “lean in." This behavior allows caregivers safe access to body parts for medical examination. This was the goal for a female Indian rhinoceros (Rhinoceros unicornis). The female was a mother whose older calf was in a nearby enclosure but visible during the training session. The team observed that the female often left the session to visit her calf or offered other behaviors for which she had a reinforcement history when they were attempting to shape the “lean in” behavior. These behaviors of offering an “open mouth” behavior and “presenting her foot” as well as leaving to see her calf were all information that reinforcement for the “lean in” behavior was insufficient. Therefore, degrees of freedom were increased as the team developed a reinforcement history for desired responses towards the “lean in” behavior. This meant the team included reinforcing instances of “open mouth” behaviors and “foot presentation” behaviors, as well as smaller approximations of the “lean in.” Eventually, the “open mouth” behavior and the “foot presentation” behaviors were emitted less frequently, and the “lean in” response increased as opportunities to shape the focal behavior grew. As the team pointed out, she showed no interest in disengaging from the session to visit her calf once the degrees of freedom were increased. Recognizing and utilizing degrees of freedom helped give the team information to reach desired outcomes.

Degrees of Freedom Can Quickly Build New Desired Behavioral Repertoires

A desired goal was to have two people stand close to an Okapi (Okapia johnstoni) for a future medical procedure. Before implementing the shaping procedure, approaching the animal with two people in her enclosure would result in the animal moving away. To achieve the desired results, the procedure involved the first author observing the animal from far enough away that the animal emitted behavior described as calm and relaxed. In this example, this included engaging in eating leaves and remaining inattentive to the people in the environment. The author slowly approached the Okapi from the front of the animal and removed herself, that is, moved away, for various responses. These responses included continuing to eat, returning to eating, putting her head down towards the food, nosing a brush on the wall, visually attending to other environmental stimuli, and more. Moving away was always available to the animal. Criteria were changed throughout the shaping process until two people stood beside the Okapi while she comfortably ate leaves. By providing numerous behaviors (degrees of freedom) that produced the same critical consequence of distance from a stimulus, the Okapi did not use the behavior of walking away from people, which was also available to her. In essence, the Okapi had a “no” response continually available. In one session, the goal of having two people stand next to the Okapi was attained.

Degrees of Freedom Can Quickly Build New Desired Behavioral Repertoires

A black bear (Ursus americanus) had a well-established training history with positive reinforcement to cooperate in her medical care. These behaviors were emitted daily in a public demonstration in a separate area of her habitat. However, when two or more people were in her off-display area, she would pop her jaw and slap her paw on the ground, resulting in people leaving. An aversive experience with a veterinary procedure in this space was hypothesized to have resulted in these responses. It was essential for the team to resolve this situation as the off-display area is the safest area for administering veterinary care when required for both the animal and staff. Because the behaviors of jaw popping and paw slapping were maintained by negative reinforcement, distance was used as the reinforcer to shape new desired responses. Like the Okapi, to achieve the desired results, the first author observed the animal from far enough away that the animal emitted behavior described as calm and relaxed. In this example, this included the bear resting in a comfortable position in her enclosure. The author slowly approached the bear from the front of the animal and then backed away for various responses. These responses included visually attending to the author, visually attending to other environmental stimuli, small shifts in body weight, changes in ear position, changes in eye position, remaining in the same position for duration, and more. Criteria were changed by adding a second person familiar to the bear. Two people then approached and backed away upon observation of the described responses. Within twenty minutes, two people were close to the bear, and the bear was emitting the desired behavioral responses. It was decided to transition to reinforce the desired responses with positive reinforcement with two people present. Preferred food items were incorporated into the procedure, and an essential first step towards training medical behaviors in the desired space was achieved in a single training session.

Additional Resources