Owners frequently report rewarding a behaviour only with food, then find that a behaviour they have never fed persists anyway. Attention itself is doing the work.
What counts as attention to a dog
The category is broader than most people assume. It includes eye contact, speaking, touching, turning towards the dog, and any change in what a person was doing.
Duration barely matters. A glance lasting under a second, delivered immediately after a behaviour, functions as reinforcement in exactly the way a treat does.
Tone is close to irrelevant for this purpose. A sharp "no" is still a person turning, looking and speaking, which is why scolding so often fails to reduce attention-seeking.
Why it is so effective
Domestication selected dogs for close social orientation towards people, and human interaction is intrinsically valuable to most of them rather than being merely instrumental.
Attention also arrives with perfect timing, which food rarely does. A person reacts within a fraction of a second, well inside the window where a dog links action to consequence.
Food has to be located, produced and delivered. Attention is instantaneous, which makes it a cleaner reinforcer than anything an owner has to reach for.
The behaviours it tends to build
Jumping up, barking at a person, pawing, nudging, mouthing sleeves and stealing objects all reliably produce a reaction, which is what maintains them.
Object stealing is the clearest case. A dog that takes a sock and is chased has been rewarded with a chase game, which no amount of subsequent scolding removes.
Behaviours that produce a large reaction from a person are precisely the ones most likely to strengthen, which is why the most irritating behaviours are often the most durable.
Using it deliberately instead
The same properties that make attention an accidental reward make it a useful deliberate one, and it never runs out or spoils appetite.
The requirement is simply to notice quiet behaviour. A dog lying calmly receives nothing in most households, while the same dog barking receives an immediate response.
Reversing that — a word or a touch delivered while the dog is settled, and nothing while it is demanding — changes which behaviours pay without introducing any correction.
Why withdrawal must be complete to register
Partial withdrawal is worse than none. Looking away while still talking, or saying nothing while watching, still delivers most of the signal.
Effective removal means the whole body turns, the eyes go elsewhere, and nothing is said, held for long enough that the dog registers the change.
Consistency across a household matters more here than elsewhere, because a single person who reacts sustains the behaviour for everybody.