I guess the difference between dogs and cats is that ultimately dogs are very needy.
Our pet pooch is a quiet and affectionate animal and likes attention. Of course in this warmer weather you need to make sure that there is plenty of water as inevitably the older dog tends to get stressed pretty quickly.
This morning she had run out of water so I filled both her bowls as soon as I got up. She was glad of the relief.
Then a dilemma for her, because while she was drinking I stroked her back.
What should she do? She was very thirsty but here was I giving her affection.
Despite the fact that we are told that it is thirst which most strongly demands our attention, she gave into the need for affection.
So the need for affection would seem to be the strongest motivator. A lot like humans really!!