I am looking for information and anecdotes about children that are about 20 months old and their tendency to throw tantrums.

My nephew has started to become belligerent when it comes to throwing tantrums. For example, he gets a hold of something that we would not like him to hold, then refuse to give it back. Usually we would try to distract him with some other attractive object and sneak the former object while he is not looking. If we even try to gently wrest the object from his grasp, he starts crying really badly. Like really badly. It is a bit terrifying.

Part of me thinks that this behaviour is learnt. He must have noticed this strategy working for him in the past so he has begun to do it more.

On the other hand, children do be throwing tantrums. I also don't want to baselessly entertain the notion of stricter parenting. As a cold, heartless individual I try to be skeptical of approaches like this to counterbalance my biases.

Thoughts and experiences?