Instinctive drift
The preparedness of animals to seek appetitive and avoid aversive stimuli is fundamental to their ability to learn through operant conditioning (Jablonsky and DeVries, 1972). However, although operant learning has been used to train various species to perform particular behaviours, the learned behaviour may drift towards an innate species-specific behaviour. For example, Breland and Breland (1961) discuss how the behaviour of pigs, trained to deposit wooden coins into a piggy-bank, repeatedly (with successive pigs) drifted toward the innate behaviour of rooting the coin into the ground.

Breland and Breland (1961) considered this as evidence of a failure of conditioning theory because the animal continued to root despite (reportedly) not receiving reinforcement for such behaviour. However, high value reinforcement may be intrinsically provided by an animal’s opportunity to perform an innate behaviour (Morris, 2016). Instinctive drift, therefore, does not constitute a failure of conditioning theory. The Brelands (1961) may have been competing with a higher reinforcement value because dopamine rises (and peeks) during the anticipation of an appetitive (Sapolsky, 2011), for example rooting and hunting.
Where training is affected by instinctive drift it may be possible to employ the Premack principle of using high probability behaviour to reinforce low probability behaviour (Danaher, 1974). For example, giving pigs the opportunity to root as reinforcement for completing the piggy-bank task.
The Brelands were game changers and hugely significant in integrating animal training with behavioural science. According to Dr. Sophia Yin, they were the best animal trainers in history. But even the best animal trainers in history ran into difficulty because of an animal’s intrinsically reinforcing natural behaviour.
Learning about the instinctive behaviour patterns of the animals in our care allows us better understand them and meet their needs. And if we are not meeting their needs we can expect problems somewhere down the line.
Shay Kelly is the author of Dog training and behavor: a guide for everyone and Canine Enrichment: the book your dog needs you to read