The reasons why dogs like people to touch their heads:

1. Leave marks. Dogs also have their own scent glands on their heads. When the owner touches the dog's head, they also spread their own scent. This behavior helps mark their territory.

2. Clean the head. It is difficult for dogs to touch their foreheads with their paws, let alone lick them, so they like their owners to touch their heads, which can help them scratch and clean their heads.

3. Feel comfortable. The skin on a dog's head is thinner and has more nerves. When you stroke their head, it will make them feel very comfortable.

4. Treat you as my mother. When the dog is young, the mother dog will often lick the head of her child. When the owner touches the dog's head when they grow up, it reminds them of their mother.

5. Be willing to surrender. When a dog lets you pet its head, it actually means that it has submitted to you. Dogs have a very strong sense of hierarchy. Only after they recognize that you are the boss, that is, the owner, will they feel comfortable handing over their most vulnerable parts to you.