Why Annotation Matters More Than Reading Speed
Speed-reading trades away comprehension; writing in the margins builds it. What the research says about both, and three annotation habits that work.
The most thorough review of speed-reading research (Rayner and colleagues, 2016) found a trade-off training doesn't remove: read faster and you understand less, and much of the apparent speed comes from skimming.
Annotation is different — when it means writing in your own words, not just highlighting. Learning research has long found that generating your own explanations deepens understanding, while highlighting on its own does little (Dunlosky and colleagues' 2013 review rated it as low-utility).
Why annotation works
The act of writing forces selection. Selection forces compression. Compression forces understanding. Reading without annotation skips two of those three steps.
There's also a graph-theoretic angle: every annotation is a candidate edge in your future thinking. A book without annotations is a node with no outgoing connections.
Three annotation systems that work
1. Single-line marginalia. Write the why this matters to me in the margin, not the gist. The book has the gist already.
2. Quote + reaction. Highlight a passage, write 1-2 sentences of personal reaction. Best for books you'll re-read.
3. Synthesis-at-end. A 200-300 word summary at the back inside cover, written within 24 hours of finishing. A good single habit if you only adopt one.
Pick one. Don't combine more than two; the friction defeats the practice.
What about digital?
Kindle highlights → Readwise → spaced resurfacing is the modern version of marginalia. It works. Whether typing beats handwriting is less settled than it sounds: an influential 2014 study (Mueller and Oppenheimer) found handwritten notes helped understanding, but later replications found smaller differences or none.
If you take notes digitally, the compensating practice is spaced review — Readwise daily emails or equivalent.
What about connections?
In Hikara, your notes on a book are part of what the AI reads when it looks for connections, so annotating gives it more to work with. If you want richer connections, annotate more.
A 2-week experiment
For two weeks, try one annotation per page in the next book you read. At day 14, compare your retention to your previous book, and see whether you can feel the difference.