Peek-A-Boo is a classic game which delights babies when your hidden face pops into view. Their delight might be due to the sounds you make or perhaps the big smile or silly expression you probably have when you do it. According to developmental psychology, a fundamental reason for their enjoyment of it is their lack of “object permanence” early in their mental development.
“Object permanence” is the understanding that objects continue to exist even when they cannot be observed. So to young babies, your Peek-A-Boo face would be the adult equivalent of teleportation. No wonder they’re excited. As they develop mentally, babies eventually understand the permanence of objects.
Here’s an observation: Some worldviews have a problem with accepting things that cannot be observed. They don’t acknowledge things which cannot be measured in the material realm. It’s like they still need to grow up 🙂