It’s a relatively known piece of “wisdom” from storytelling:

“The more specific we are, the more universal something can become. Life is in the details. If you generalize, it doesn't resonate. The specificity of it is what resonates.” [https://www.brainyquote.com/quotes/jacqueline_woodson_882873]

You can repeat a generalization over and over again. It sounds right — but it doesn’t stick. You can’t translate it into your own practice. You learn the words, but not the intuition.

Telling concrete stories helps us learn the intuition, too.

This really reminds me of the concept of elaborative encoding whereas we learn by connecting facts with preexisting knowledge [0]. Abstract things do not stick because we have less touch points to connect them with. The Baker Baker paradox for instance describes the fact that we are much more likely to remember that a person is a baker than the more abstract fact that his name is Baker [1].

[0] https://en.m.wikipedia.org/wiki/Elaborative_encoding

[1] https://www.psychologytoday.com/us/blog/mental-mishaps/20100...

>Could it be that longer books are almost a natural spaced repetition system for ingesting content?

I might buy the 'fiber' argument as it were, if it weren't for literature's existing power to convey in compact form already.

Aesop seems miles ahead of the modern self-help crowd here; if anything, there's something about couching information in metaphor that makes it particularly satisfying to digest, which is why we can teach children about boys who cry wolf with more efficacy than simply preaching honesty - which children put to more credible use in examining their teachers' hypocrisy.

I do like your fiber analogy.

I wholeheartedly agree metaphors are a multiplier to information transfer, but I can't say I've seen a deep dive into the psychology of why beyond simple literature class reasons.

My guess is when given a metaphor our brains just don't have to do as much work to frame the concept and understand it, and retention is better as it's condensed.