Learning by reward
How reinforcement learning works: a program gets a score instead of correct answers, and the score can teach the wrong lesson.
- 9min read
- 29questions
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You keep more from recalling something once than from reading it twice.
In a 2006 experiment, students read one passage twice, and read another once and then tried to recall it. A week later they remembered 42% of the first and 56% of the second. So every article here comes with questions, and the EdenMind app brings each one back just before you’d forget it.
Learning with no one to mark the answers
How machines learn from data nobody has labelled, by sorting it into groups, compressing it, and predicting the parts that were hidden from them.
- 8min read
- 26questions
How much is a surprise worth?
Claude Shannon measured information by how surprising a message is. The same measure explains file compression and how language models are trained.
- 9min read
- 31questions
Changing your mind by the numbers
Bayes’ rule says how far new evidence should move a belief, and why a positive test for a rare disease often means less than it seems.
- 9min read
- 28questions
Thinking in lists of numbers
Vectors and matrices: how a photo, a word or a film becomes a list of numbers, and how search, recommendations and neural networks compare them.
- 8min read
- 29questions
When famous findings fall apart
Many celebrated psychology results shrank or vanished when other scientists repeated the studies. Why that happened, and what the field changed.
- 9min read
- 30questions
What really happened in the Stanford prison
In 1971 Philip Zimbardo ran a mock prison in a Stanford basement and stopped it after six days. What he concluded, and what the archives showed in 2018.
- 8min read
- 27questions
The two speeds of thought
Why a quick answer can feel certain and still be wrong, what careful thinking costs, and when a gut feeling can be trusted.
- 9min read
- 31questions
Why prices rise
What inflation is, how it is measured, what pushes prices up, and why central banks aim for 2 per cent a year instead of zero.
- 8min read
- 30questions
Ibn al-Haytham told his reader to make himself an enemy of everything he reads.
He wrote it of Ptolemy, whom he admired, and asked the reader to suspect himself too. The pieces here are written in that spirit, for the readers who inherited it. Where scholars of the Muslim world shaped a subject, they are named for what they did: al-Kindī on breaking ciphers, the earliest account we have, or Ibn al-Nafīs on the route blood takes through the lungs, three centuries before Europe found it.
Mathematics & Logic
Secret codes
How ciphers work, how counting letters broke them for centuries, and why modern encryption depends on a key and on maths that is hard to reverse.
8 min read
Transformers
The design behind chat assistants: how text becomes numbers, how each word is weighed against every other, and why a fluent reply can still be false.
9 min read
Deep learning
How a neural network learns to recognise pictures from examples instead of written rules, why that took decades to work, and where it still fails.
8 min read
Physics
The search for a steady beat
From sundials and water clocks to quartz and caesium: how each clock counts something that repeats, and why the second is now defined by an atom.
9 min read
Ibn al-Haytham
The eleventh-century scholar who showed that we see by light entering the eye, and who made experiment the test of a theory in optics.
8 min read
Electricity
Charge, current, voltage and resistance, from static on a doorknob to the circuits in a house, and why a bird can sit safely on a power line.
9 min read
Chemistry
How soap cleans
A soap molecule holds water at one end and grease at the other. That is how it lifts oil off a plate, and how it breaks some viruses apart.
7 min read
Carbon chemistry
How one element makes diamond and pencil lead, fuels, alcohols and plastics, and the molecules of every living thing.
8 min read
Metals and materials
Why gold is found as nuggets and aluminium never is, why a little carbon turns soft iron into steel, and why a block of zinc keeps a ship from rusting.
9 min read
Biology
How animals find their way
How birds, sea turtles, salmon and desert ants find one particular place, using the sun, the stars, the Earth’s magnetic field and smell.
8 min read
Ecosystems
Food chains and webs, the flow of energy, the cycles of carbon and water, and what follows when one species goes missing.
8 min read
Food and fuel
Why food has to be taken apart before you can use it, why the stomach does not digest itself, and where in a cell the energy of a meal is finally released.
8 min read
Psychology
How habits work
Why a habit is set off by a place or a cue and not by an intention, how long one takes to form, and what helps to change one.
8 min read
The testing effect
Recalling an answer from memory strengthens it more than reading it again, so a quiz can teach as well as check.
6 min read
Spaced repetition
The same hours of study last far longer spread out than done in one go. Why the gaps help, and how a review schedule sets them.
7 min read
Society
The medium is the message
Marshall McLuhan’s claim that the way a message reaches us shapes us more than the message does, and the main objections to it.
8 min read
Media & persuasion
How news is chosen and worded, how persuasion and propaganda work on us, how numbers mislead, and why checking before you share matters.
9 min read
Knowing the past
How we know what happened before anyone alive was born, from sources and how they are tested to Ibn Khaldūn’s rule for catching the impossible.
9 min read
It’s easy to believe you knew an answer once you’ve seen it.
Most flashcard apps show you the answer and then ask you to mark yourself. In EdenMind you say it first and your phone marks it, allowing for an accent, a plural or a number said in words. Your voice never leaves the phone.
Choose an article 
A ten-minute read 
Answer out loud 
Check your answer 
See what’s due next
