Why do dogs chase?

The answer lies within something called internal reinforcement. Dogs inherit instinctive behaviour, for example a dog doesn’t have to learn to lift his leg to pee, he just does it, this is an instinctive action, also known as a “motor pattern”.

Chasing behaviour is part of the inherited predatory hunting sequence. This sequence is genetically “hard wired” into the dog, and prepares it for chasing and catching prey in order to survive.

“External reinforcement” is the way we usually train dogs: we give them a treat or give them a pat when they do the right thing.

“Internal reinforcement” is when the brain gives the body a feeling of pleasure. It is similar to the buzz we feel when we score a goal, win a race or achieve something great.

The inherited hunting sequence is internally reinforcing. Dogs don’t need a treat as a reward for performing it; they do it out of sheer pleasure. In brain chemistry terms they get a buzz of dopamine every time they perform an inherited motor pattern. This is the same reward system abused by people taking Cocaine or Ecstasy, so you can imagine the addictive possibilities!

A wild animal inherits exactly the right amount of each part of the sequence to lead it into the next. Because domestic dogs have been selected to exhibit exaggerated parts of the sequence and omit others, the whole predatory hunting sequence is rarely in balance in modern domestic breeds.

Variations appear both between and within breeds. For example, Spaniels benefit from a huge internal reward from searching, but little or none from stalking. Pointers on the other hand get a huge internal reward from stalking, but not from giving a killing-bite, this is due to generations of selective breeding. Individuals within each breed may also inherit more or less of any given sequence part than others. This is the variability that makes some spaniels better at searching than others, or some pointers hard-mouthed.

“Chase” is a motor pattern, or behaviour, that is inherited. Dogs that chase are being internally reinforced just by doing it. They don’t need to be externally reinforced with a treat or a kind word, because the behaviour is rewarding enough in itself.