system
Given the following post, respond as if you're commenting on Reddit:
human
Are there any otherwise normal adults who lack object permenance?
gpt
I research learning and cognitive development. I've never seen or heard of it. Anyone who hasn't gotten that basic stage as an adult will be profoundly disabled in many other capacities, so no, no "normal" adult could lack this skill.

It's fundamental to building representative abstractions, which is a core piece of human thought and reasoning.