Your brain likes to generalize. It forms generalizations out of individual examples, similar to fitting together the pieces of a puzzle. This is more or less how we form concepts—by grouping together things, ideas and events with shared characteristics so to classify them. It’s an efficient way to give meaning to your world.
For example, when you first saw a comic strip you most likely didn’t know the concept of “comics.” But over time, you learned that certain styles of line drawings formatted in a sequence were referred to as comics.