She likes it because I give her a small treat at the exact moment when each paw goes into the liquid. I have only to pick up the small container with the chlorhex solution and she rushes over to get started.
I got the idea from noticing that the vet suggests I offer her a treat just as he gives her a vaccination. I must say, though, she still doesn't like injections.
When she was a tiny puppy she didn't like being brushed, so we started acclimatising her to grooming by holding the brush against her skin and giving her a treat; we gradually moved on to brushing and now she loves the actual grooming. In psychology terms I suppose she has associated grooming with a pleasant experience and now she doesn't need treats. I'm not sure it's a case of classical conditioning, as in the original Pavlovian experiements. After all, she might simply like being brushed.
She sure loves the brushes - the toothmarks on the handles show just how much.
In looking around for information on Pavlov's experiments with dogs I came across a discussion of how humans react to a stimulus paired with the smell of peanut butter or vanilla. It seems that we're not much different from dogs.
I must admit that when I walk into the house one of the first things I do is stroll over to the fridge or the pantry to see if there's any chocolate to be had.
The discussion said, in part:
Some researchers think that visual signals encourage certain behaviors. For example, in this latest study, the visual signals were the abstract pictures. However, many things can become visual cues in daily life. It is possible that some people are conditioned to want fattening or sweet foods when they go to a particular restaurant; perhaps other people eat bags of potato chips when they watch TV or drink too much alcohol when they are with certain friends. People who want to change certain eating behaviors may benefit from changing their environment. A change in a person's environment may help to avoid behaviors that they hope to change.
We're careful to make sure Penny has a healthy diet. It's a pity we're not so conscientious in looking after our own health.