I really don't see how it makes a child not need praise. they got praised for what they did right and good job does basically the same thing. yes they know exactly WHAT they did right but I don't see how it would stop them from "needing praise for everything they do"
as for the dog training thing. I can't say I ever really used markers. I praised them at the moment they did what I was asking for. or do you mean markers as in the word sit? is that a marker? lol I really don't know.
Maybe that's why I understand this so easily, because I'm a clicker trainer.
A clicker is a marker. A marker is a sound that is used to communicate clearly what behavior the dog is doing that is getting him the treat. You pair the marker with treats, so that the dog understands that the marker tells him that a treat is coming. If you want your dog to sit, you click right at the moment he put his butt on the ground, to let him know exactly what behavior he did to get a treat.
It becomes more useful when you're shaping a behavior. Let's say I'm trying to shape my dog to retrieve a dumbell. First I want him to look at the dumbell. Well, he's probably going to be looking everywhere, and at the same time he's going to be walking around, listening to other things, and doing any number of other behaviors. At some point he will give a fleeting glance to the dumbell.... and I click that glance and reward the dog. After a few reps, he will start to figure out that looking at the dumbell is what is getting him a click - and a treat - and will start purposefully looking at the dumbell.
If I don't use a clicker, if I just treat my dog for looking at the dumbell, the communication is not as clear; it will take him much longer to figure out what behavior he's doing that gets him the reward..... is it looking at the floor? Is it stepping sideways? Is it panting? Is it whining? Is it looking for the treat? Yeah, he'll probably figure it out eventually, but it will take much longer.
Most trainers will probably get frustrated that it goes so slow, and start pointing at the dumbell, or waving it around, to prompt him to look at it; which will cause the dog to just wait until the human
prompts the behavior he should do.... making the dog rely on the human to do the correct behavior instead of offering it on his own. All because he's not getting clear feedback about what he's doing that's right.
In your example of the ladder climbing: Let's say my kid climbs the ladder and I say good job. He's not sure why I said good job, he doesn't really know what he did that was so good. Next time he climbs the ladder, I happen to not be watching and don't say good job; since he didn't know what he did right the time before, he assumes that he did something wrong this time to not get a good job... so he calls to me "did I do good?" and I say "yeah." Well, he still doesn't know what he did right. So every time he will want to know if that was a good one or not.
But, let's say he climbs the ladder, and I say "you climbed it really fast that time, and held on really well with your hands, good for you!" He knows exactly what he did well. Next time he climbs and I happen to not be watching; he calls to me "I climbed even faster that time!" And I say, "Oh wow, you're getting really fast!" He didn't need me to tell him how fast he climbed, he could feel it was faster than the last time; and instead of looking for me to tell him whether he did right or not, he could brag at how well he knew he did.