If you're not a pet owner, it's easy to dismiss the idea of dog psychology as a symptom of a 21st-century obsession with psychobabble. But, as most vets will tell you, understanding the way the canine mind works is the key to preventing the sort of anti-social behaviour that leads to a dog being labelled aggressive.
As the former French president Jacques Chirac can testify, the sort of life changes that can affect human behaviour can also have an impact on their dogs.
When Mr Chirac left the Elysée Palace in May 2007, he was quick to admit he found retirement difficult. His dog, a white Maltese terrier named Sumo, found the change just as difficult, however, but was unable to articulate his distress.
From the grand corridors of the presidential palace, Sumo found himself downsized to an apartment on the Quai Voltaire, and began to suffer from depression. When Sumo attacked Mr Chirac for the third time, the former president reluctantly rehoused him.
The vet and author Bruce Fogle is in no doubt that humans and animals share the ability to feel emotion. "With dogs in particular, we seem to be able to read their behaviour. You can tell when a dog is angry or unhappy and in the same way they seem to be able to interpret our emotions."
Animal emotions do not work in exactly the same as ours, of course. Dr Fogle explains: "Humans are able to to analyse emotion in a more sophisticated way. But perhaps if we peeled back the onion skins, we would find something more like the way dogs think."