system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do people with amnesia forget who they are/who the people around them are, but dont forget what basic things are in the world, such as cars, planes, appliances etc.
gpt
This has to do with how our memories are called upon, and in the case of your question what exactly constitutes a "memory." 

Amnesia occurs when there is damage to the pathway in the brain that we use to either store or retrieve memories. This means amnesia can be retrograde (forgetting the past) or anterograde (not remembering new information).

With object recognition, this pathway isn't used at all. There's a separate set of conditions associated with brain damage that affect this, and they don't affect memory. 

For example damage to the temporal lobes can prevent someone from naming an object that they see, yet they can still know what it is. This means someone can't look at an airplane and say "that's an airplane," but if you asked them to "point at which picture is an airplane," (giving them the word) they could do it. The opposite is also possible. Meanwhile, a person with amnesia will recognize the airplane, but might not be able to describe to you how an airplane works.

**In short because recognizing these things has more to do with language and is processed in that part of the brain, separate from the part the handles your name and birthday.**