My internal argument goes something like this: on one hand, if the behaviour is the same how can you claim the intent is different? But on the other hand, how do you define deceptive behaviour without intent?

Here's a thought experiment: suppose someone had no short-term memory but had a dog who was trained to ask (as dogs do) for his meal each day. If the dog decided one day to ask for an extra meal, is he lying, or is he responding to a reward? And if the answer is that he isn't lying, because the dog doesn't differentiate indicating he hasn't eaten (which would be a lie) and asking for a meal (which wouldn't), isn't this true of any way that a dog could "lie"?