Anticipatory behaviour is the manner in which the animal behaves when awaiting a future event, positive or negative. Pavlovian conditioning anticipatory behaviour is one of our tools for assessing animals' emotional states and well-being. Nowadays, welfare is increasingly monitored in the animal world, which is why this method is being applied more and more. Welfare is a physical and mental state of an animal in relation to the conditions in which the animal lives and dies. This technique is based on the fact that an animal in a suitable environment is less sensitive to the expected reward. For instance, an increase in activity in anticipation of a reward is a signal of stressful conditions.
Animals in lower welfare could show a greater anticipatory behaviour and a greater sensitivity to rewards.
The reward is most of the time food-related, but, depending on the studied species, food rewards can be substituted by play opportunities or better housing, for example.
What is an anticipatory behaviour?
It is a behaviour that is dependent on expectations and beliefs about the future. This influences decision making, internal preparation as well as learning. And is displayed in the period between the signalling of an upcoming event, and the event itself. The famous experiment of Pavlov showed for example that dogs were salivating before getting a reward.
Pavlov experiment
Pavlovian conditioning, also known as classical conditioning, is a learning process in which an organism learns to associate a neutral stimulus with a stimulus that naturally produces a specific response.
You can see the dog salivating at the at the sight of food. The food is the unconditioned stimulus (UCS), and salivation is the unconditioned response (UCR)—a reflexive, unlearned specific behavioural response.
Before conditioning, the dog hears the sound of a bell. The bell, at this point, is a neutral stimulus (NS) because it doesn’t cause any salivation on its own.
The bell, the neutral stimulus (NS) is repeatedly paired with the presentation of food, the unconditioned stimulus (UCS). Each time the dog hears the bell, food follows shortly after. Over time, the dog begins to associate the sound of the bell with the arrival of food.
After consistent pairing, the bell becomes a conditioned stimulus (CS). Now, even if no food is presented, the dog salivates when he hears the bell. This learned reaction is the conditioned response (CR).
Food (unconditioned stimulus) --> Salivation (unconditioned response)
After conditioning
Bell (Conditioned stimulus) --> Salivation (Conditioned response)
The experiment
Training with different bell signals to expect either:
Positive predictable reward: pieces of salmon (unconditioned stimulus 1)
Positive unpredictable reward: feed related à dog biscuits, salmon, cattle humerus, or not feed related à a tennis ball or a wooden chewing stick (unconditioned stimulus 2)
Negative predictable reward: capture with a neck tong, known to be aversive in farmed foxes (unconditioned stimulus 3)
Each of the unconditioned stimulus are paired during a certain training period with a specific bell signal. The foxes learn to associate each bell sounds to the three different rewards. After conditioning, the bells become a conditioned stimulus.
The researchers observed during 10 minutes between the bell signal and the arrival of the reward, the anticipatory behaviour performed by the foxes.
The study of anticipatory behaviour of foxes (Vulpes vulpes) allows better understanding of the welfare of the animal. In the study of Moe et al. (2006), the silver foxes show signs of expectation before the positive rewards. Indeed, the posture of the fox with ears erect and its position at the front of the cage are interpreted as signs of excitement.
Example with the first positive predictable reward (piece of salmon):
Positive predictable reward (Unconditioned stimulus 1) --> Signs of excitement: at the front of the cage, ears up (Unconditioned response 1)
After conditioning
Bell 1 (Conditioned stimulus 1) --> Signs of excitement: at the front of the cage, ears up (Conditioned response 1)
The anticipatory behaviours to a negative stimulus, “capture with a neck tong” were also recorded. The results show that silver foxes can distinguish the difference between an upcoming positive or aversive treatment. The foxes tended to remain at the back of the pen while they were at the front when anticipating a positive reward. During anticipation of the aversive treatment, the foxes showed a reduction of activity level with flat and backward rotated ears. This decrease of activity demonstrates no arousal for the forthcoming event.
It is highly debatable that a certain activation of an animal's emotional and physical states can be linked to only positive or negative outcomes. A pessimistic emotional state can be predicted by a decrease in activity before a negative event during the anticipation phase. But to assess this emotional state, other methods could be used such as the appearance of stereotypies (Brilot et al., 2010) or thanks to the use of "cognitive judgement bias" (Paul et al., 2005).
Sources:
Brilot, B. O., Asher, L., Bateson, M. 2010. Stereotyping starlings are more “pessimistic.” Anim. Cogn. 13(5), pp 721–731
Moe R. O., Bakken M., Kittilsen S., Kingsley-Smith H., Spruijt B. M. 2006. A note on reward-related behaviour and emotional expressions in farmed silver foxes (Vulpes vulpes)—Basis for a novel tool to study animal welfare. Appl. Anim. Behav. Sci. 101, pp 362-368
Paul, E. S., Harding, E. J., Mendl, M. 2005. Measuring emotional processes in animals: The utility of a cognitive approach. Neurosci. Biobehav. Rev. 29(3), pp 469–491
