At ds's 18-24 month developmental check (he's 21 mths.I mentioned to her that he had got into the habit of smacking myself and dh during his tantrums, and she said that if he does this I should put him onto a naughty step/chair (without warning) for 2 minutes. I've no problem with this but I'd always thought he was a bit young for that yet and that children are unable to grasp the concept of discipline before the age of two, I don't want to confuse him. She also said that I should avoid saying 'no' or 'stop' when he smacks/throws things, which I found a bit wierd tbh. What do you make of this?