The “counting” tricks (and the Clever Hans effect)
Clever Hans: a horse, not a dog that could count
It all starts with a horse, not a dog. Around 1904, in Berlin, a horse named Clever Hans (“Hans the clever one”) belonged to Wilhelm von Osten, a maths teacher. The horse seemed to solve sums: he tapped his hoof the right number of times. In 1907, the psychologist Oskar Pfungst showed that Hans failed almost every time in one specific case: when the person questioning him could no longer see him. As long as that person knew the answer and stayed within his field of view, he got it right 89 times out of 100. Hidden from his sight, he dropped to 6 times out of 100. Without meaning to, that person released a tiny flicker of body tension, in their posture, their breathing, their face, at exactly the right moment, and the horse stopped on it. Your dog does exactly the same: he watches for the smallest movement to know when to fall silent.
And that reading of the body is far more impressive than any sum: most dogs decode our gestures and our expressions with remarkable subtlety, a genuine social talent. What he's showing you there is social reading, not a furry calculator.
What the audience thinks it sees, and what is really going on.
The myth (the received idea)
The reality (what the science says)
Dogs do have an approximate sense of number: they tell “more” from “less”, but nothing that resembles real addition.
From the first bark to the secret signal
Before you start, your dog needs to know two things already. First, to bark on your cue and to go quiet on your cue (the “hush”), calmly, without winding himself up: that's what the guide “Speak and hush” teaches. Then, to work a trick on rewards, with no coercion at all, which the foundations guide “Teaching a trick with rewards” covers. If either of the two isn't solid yet with you, start there. The point here isn't to fool anyone: it's to show a lovely dialogue between you and your dog, owned for what it is. One worry comes up often: will teaching him to bark make him more of a barker? No, as long as you only reward barking when you've asked for it, and never a “woof” you didn't request.
Only move on to the next step once the previous one is clean.
One bark = one unit
Reward single barks that you can count one by one: your dog barks once, you immediately say your marker word (a short word that's always the same, “yes!”, telling him to the second that he's won it), then you hand over the treat. You're after a tap dripping at a steady rhythm, never a jet that runs away with itself. He's got it when he gives you three or four crisp, well separated “woofs” on request, without building up excitement.
String several barks together
Use the same “speak” cue from the previous step, but give it again straight after each “woof”, so he barks twice, then three times in a row. This time you only reward at the end of the little run, and you cut it off with your usual “hush”. That run is what you'll learn to stop with a discreet gesture in the next step. Move on when he strings two or three barks together and stops dead on your “hush”, several times running.
Set up a discreet stop signal
Choose a tiny gesture you can repeat identically every time: a blink, a slight drop of the shoulders, a hand opening softly. Make that gesture just before saying “hush” as usual, several times in a row, then say “hush” more and more quietly, almost silently, until you're only making the gesture. For him to catch a gesture that subtle, he needs to be facing you and looking at you: stand in front of him, and if he turns his head away, say his name or wait until he comes back to you before asking for another bark. He's got it when he stops on the gesture alone, as reliably as on the spoken “hush”, three or four times in a row. Own that signal as the real heart of the trick: there's nothing else to hide.
Stage the “question”
You're the one counting, silently, and you pick the number in advance: for “2 and 1”, you wait for three barks. Ask the fake question out loud, give your barking cue, count the “woofs” in your head, and give your discreet stop signal right after the last one you wanted, before he launches into another. Praise him at once. If he gives you one too many, it's only a trick: start again calmly, or play it for laughs in front of your audience. Get the sequence of question, barks, stop on the right count right three or four times in a row before you show it for real. In front of others, tell it like it is: “look how he reads me without a word”.
The blind test (the Clever Hans challenge)
Ask someone who doesn't know the answer to put the question in your place, or step out of your dog's field of view at the moment you'd give your stop signal. The act loses its accuracy straight away, and that's good news worth showing off proudly: proof that your dog was reading real cues, rather than doing sums.
There's no magic number of repetitions for this one: pair your stop gesture with the reward every single time, one tiny step of progress after another, never forcing him. Keep the sessions very short, and stop while your dog is still asking for more.
If your dog already barks too much, if he lives in a flat where every bark is a problem, or if his barking comes from anxiety, give this one a miss: it isn't the right act for him. That calls for a trainer or a behaviourist working on the cause, not one more trick to teach him.
- Pfungst — Investigation into the horse “Clever Hans”: responding to involuntary body cues, hence the requirement for double blind testing (1907)
- AVSAB — Position Statement on Humane Dog Training (putting a behaviour on cue with positive reinforcement, without coercion) (2021)
Going further
Frequently asked questions
Can dogs count?
Not the way we do. Dogs have a rough sense of “more” and “less”, not arithmetic with symbols. Faced with a result that doesn't add up, they often look for longer: a sign of that sense of quantities, not proof that they're really counting.
How do I teach my dog to count?
In reality, you're not teaching him to count: you're teaching him to bark until your stop signal. First you need a solid bark and a solid “hush” on cue, which the guide “Speak and hush” covers. Then you mark single barks with a marker word (“yes!”), and you set up a discreet stop gesture that you give on the right count. It's an act of communication, not of maths.
What is the Clever Hans effect?
The name comes from a horse who seemed to do sums by tapping his hoof. In 1907, the psychologist Oskar Pfungst showed that he stopped as soon as the person questioning him released, without meaning to, a small flicker of body tension. Your dog does the same: he reads your involuntary micro movements, not the sum you're setting him.
My dog barks the right number of times, how does he do it?
He's watching you. He barks in a run and stops when your body tells him “stop”: a blink, shoulders dropping, a breath being held. You are the unwitting author of the result, and that's an impressive piece of social reading on his part.
How do I know whether my dog really understands?
With the blind test: have the question put by someone who doesn't know the answer, or step out of your dog's field of view at the moment of the stop. If the accuracy collapses, he was reading your cues. Never test this kind of learning without being able to guide your dog.
Is this trick right for every dog?
No. Give it a miss if your dog already barks a lot, or if his barking comes from anxiety: reinforcing it could feed a real problem, and that gets sorted out with a professional, not with a trick. For other dogs, short, calm sessions are all it takes, never letting the barking run away with itself.
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