There are always variables for how anything perceives. Babies are no different. But for the sake of understanding, think of coming into this life, as opting into a "video game program". At first, you are not fully integrated. Neither are your senses. You have to acclimate to it. The perspective you hold is still much more the perspective of your eternal self. You have not fully forgotten who you really are. You have still not forgotten that your experience is coming in response to what you give your attention to. This is why babies are so good (especially until they are about two) at ignoring things that they do not want to pay attention to. Gradually, your attention gets trained. You learn to focus on things your parents want you to focus on whether or not they make you feel good to focus on.