Training with positive reinforcement (PRT)
Primates in the laboratory need to interact with humans for both welfare and research aims. For instance, to ensure optimal welfare, the animal's blood needs to be sampled regularly and their weight needs to be measured. For that purpose, the animals need to be moved from their home enclosure.
Typically the animals sit on a small chair, which is then moved by the researcher to a weighing machine. Using PRT techniques in training the animals to voluntarily sit on the chair is a great way to increase the bond between researchers and animals whilst also significantly reducing stress-associated procedures and husbandry routines. PRT techniques typically involve clicker training and food rewards similar to what is used when training domestic animals (e.g. dogs).
Video illustrations of different types of positive reinforcement training
Primate chair habituation
The animal is trained by the use of food rewards to come and sit in the primate chair.
The primary step in the clicker training process is establishing the significance of the “click” sound. A hand-held box clicker serves as the conditioned reinforcer. The animal is presented with the conditioned reinforcer (the click sound), immediately followed by a positive reinforcer (food reward).
Clicker and Target Training
Training begins by presenting a target (monkey toy) to the animal. The clicker is hidden to ensure that the animal focusses on the target. Each time the animal moves closer to the target, the conditioned reinforcer (clicker) is presented, followed by the positive reinforcer (food reward). Subsequently, when the target is touched, the conditioned reinforcer is immediately presented followed immediately by the positive reinforcer.
Hind limb reach and grasp
The same clicker and target training, but the animal must reach and grasp the target with the hind limb.
The experimenter trains the animal to touch their hand in order to win its confidence for a subsequent task which is different and requires direct hand contact.
The experimenter trains the animal to hold their hand in order to win its confidence for a subsequent task which is different and requires direct hand contact.