ELI5: What is happening when you temporarily forget something you 100% know, such as a name?

Our brains (and neural networks in general) store similar concepts "close together." That doesn't mean each idea we have has its own spot in our brain, just that its easy to move from one concept to a similar concept in terms of effort or, more precisely, metabolic energy. So if someone asks, "What has feathers and webbed feet?" your brain lights up all the neurons that have learned to recognize feathers and also the neurons that recognize webbed feet. Then it looks for concepts that it can move to easily, like "ducks." However, your brain might also light up "mallards," but it would be confusing to have both ducks and mallards lit up at the same time. So when your brain latches onto ducks, it automatically suppresses similar ideas, such as mallards.

This relates to forgetting things because... You meet someone who you know is named Bob, but for whatever quirk of the chemistry and physics that govern our brains, you latch onto another name Tom. Now, even though you know that name isn't correct, you can't think of Bob. This is because the idea "Tom" is suppressing the idea "Bob."

TLDR: This link explains it better than I can.

/r/explainlikeimfive Thread