My youngest is not motivated by rewards or punishment. He just doesn't care. If I reward him with something good, he will accept it, but the loss of the reward

My youngest is not motivated by rewards or punishment. He just doesn't care. If I reward him with something good, he will accept it, but the loss of the reward will not motivate him to do things. Similarly he won't like being punished but the punishment won't stop him from doing things that he wants to. His teachers told us the same thing, which creates problems because when he decides he wants to misbehave, there's nothing that will motivate him to behave until he chooses to behave. I don't spank him, but I'll give him timeouts but I've come to terms with the fact that he is motivated by different things than other kids. The techniques in the article won't work for my child at all. Hopefully he will mature and we can reason with him in other ways.