Your baby is learning about his relationship with you. When he does something, you respond. That alone teaches him that you care. He learns from the nature of your responses, too.
Why does my baby keep dropping toys and wanting them back, only to drop them again?
When your baby repeatedly drops a toy, spoon, or other object—no matter how many times you retrieve it for him—you may find yourself thinking, He needs to learn to hold onto his things. But there's an entirely different kind of learning going on, and your baby's repetitive actions are serving an important purpose in his developing mind.
Your baby learns about the world both by observing it (and you) and by interacting with it. That's why he grabs, mouths, shakes, crinkles, and bats at so many different objects. Each of these experiences is a way of learning: what an item feels like, how heavy it is, what it's used for, what it smells and tastes like, and what it can do and what can be done to it.
Trial and error is a big part of this learning. If he bangs a cup on a table, what does it sound like? If it's banged on a high chair, does it make the same sound? What happens if he bangs it on Mom's head? Or his head? Behavior that looks like silly or random is actually your child deep in scientist mode.
He wants to know what happens when different objects are dropped, or when objects are dropped from different heights or in different ways. Where do they go? Do they always end up in the same place? What does it sound like when it lands? What happens next?
Your baby is also learning about his relationship with you. When he does something, you respond. That alone teaches him that you care. He learns from the nature of your responses, too. Are you happy? Angry? Exasperated? Your baby is absorbing all this useful information. But it takes many different tries to get the message across. You didn't like it when I threw the toy off this side of my high chair, but what about that side? You didn't like it when I threw my spoon, but what about my cracker? What about my bowl?
And, to some extent, your baby likes to drop things at this age simply because he can. For much of their early months, babies are better at grasping objects than letting them go. Once they begin to develop the fine motor control that allows them to release something from their hand at will, it becomes something they want to practice … and practice.