05_Body_and_Brain — which claims about sleep, exercise, food and the brain should a learner believe?¶
Level: 101 · for anyone who has read a thread of "brain hacks" and wondered which ones are real
Every page in the other chapters rests on a program that runs. The claims in this chapter cannot: no program shows what sleep does to a memory, or what a walk does to attention, without inventing the data. They are still claims a learner meets every week, in books, videos and AI summaries, mixed together with no sign of which rest on fifty years of experiments and which on one study of rats. So this chapter does the next best thing to a program. Every claim carries a grade, and the page says where the grade comes from.
| Grade | Means |
|---|---|
| well established | many experiments on people, replicated, in more than one lab |
| good evidence | consistent studies on people, but fewer, smaller, or with a caveat the page names |
| weak | a few small studies, mixed results, or evidence mainly in animals |
| speculative | a mechanism story with no direct test on learners |
The pages give no doses, recommend no supplement or drug, and offer no medical advice. Where you might want any of those, they say to ask a doctor.
| # | Page | The question it answers |
|---|---|---|
| 1 | How memory works | What happens between reading a page and remembering it a month later, and which study technique acts on which stage? |
| 2 | Sleep | What does sleep do for a memory, and what does a night of cramming cost? |
| 3 | Exercise | Does a run before studying help, and what is BDNF? |
| 4 | Food and supplements | Does anything you eat or swallow make you learn faster? |
| 5 | Brain chemistry | What do dopamine, acetylcholine and norepinephrine do, and what follows for a learner? |
| 6 | Mindset and motivation | How much do growth mindset, self-efficacy and stress management actually change, and what about imposter syndrome? |
The through-line¶
The evidence is strongest exactly where this library already has lessons, on testing yourself, spacing and interleaving, and on sleep. It thins out fast as the claims get more biological. That pattern is the chapter's one lesson: when a summary moves from "space your reviews" to "this raises your BDNF", it has usually moved from well established to weak without changing its tone. The first chapter's habit, checking a claim before trusting the feeling that it is true, is what these grades are for.
Po polsku, w skrócie¶
Twierdzeń z tego rozdziału nie da się pokazać programem: żaden program nie sprawdzi, co sen robi z pamięcią, bez wymyślania danych. Uczeń spotyka je jednak co tydzień, w książkach, filmach i podsumowaniach od AI, pomieszane tak, że nie widać, które opierają się na pięćdziesięciu latach eksperymentów, a które na jednym badaniu na szczurach. Dlatego każde twierdzenie ma tu ocenę: dobrze ugruntowane, dobre dowody, słabe albo spekulacja, i strona mówi, skąd ocena pochodzi. Strony nie podają dawek, nie polecają suplementów ani leków i nie zastępują lekarza. Dowody są najmocniejsze tam, gdzie biblioteka ma już lekcje (sprawdzanie się, powtórki, przeplatanie, sen) i szybko słabną, im bardziej biologiczne staje się twierdzenie.
A note on the pages¶
None of these pages has a program, and that is the point of the grades. The sources are named on each page and gathered on the resources page.