Pet parrots are not only VERY smart, they are also excellent readers of human and parrot body language as well as humans' different tones of voices and can easily tell the difference between an "I am happy with you" tone and an "I am NOT happy with you" one. And, because they love us and are naturally geared toward pleasing their flock members, they would always try to do what would result in a "I am happy with you" tone of voice and praise.
This bit I agree with 100%
However, in the case of "NO", I disagree, because I feel they see it as attention and a reaction to what they did. They might understand that it was something bad they did, but still do it because it got a funny reaction. This also happens when someone makes a ruckus when getting bit, or removes their hand - they teach their parrot that biting gets it the result it wants, for you to stop what you were doing. Or just because it wants a reaction.
Stitch bites my ears if he's allowed on my shoulders, to get my attention. Its impossible to ignore and thus I dont allow him there. A no, or any other reaction just makes him happy because he got my attention from the bite.
Everyone is free to try whatever they feel work for them, but I tried the whole "NO" and setting the bird down thing, and the only thing it lead to was Stitch starting to dislike hands. Had to work through that, which took time.
I strongly believe in prevention, reinforcing good behaviour and ignoring bad.






