One reason / we think we forget most of what we learned in school / is that we underestimate / what we actually remember.

Other times, / we know we remember something, / but we don’t recognize that we learned it in school.

Knowing where and when you learned something / is usually called 'context information', / and context is handled / by different memory processes / than memory for the content.

Thus, / it’s quite possible / to retain content without remembering the context.

For example, / if someone mentions a movie / and you think to yourself / that you heard it was terrible / but can’t remember where you heard that, / you’re recalling the content, / but you’ve lost the context.

Context information / is frequently easier to forget than content, / and it’s the source of a variety of memory illusions.

For instance, / people are unconvinced by a persuasive argument / if it’s written by someone who is not very credible / (e.g., someone with a clear financial interest in the topic).

But in time, / readers’ attitudes, on average, change / in the direction of the persuasive argument.

Why?

Because readers are likely to remember the content of the argument / but forget the source / ― someone who is not credible.

If remembering the source of knowledge / is difficult, / you can see / how it would be challenging(→easy) / to conclude you don’t remember much from school.