Grey Matter
How these abilities work, what the common tests measure, and where the popular claims run ahead of the evidence.
Cognitive testing
What these tests actually measure, where the popular numbers come from, and which of the claims made for them survive contact with the evidence.
The five ages of the brain, and what they do to a brain-age score
Brain wiring changes direction four times across a life, and the tissue keeps its own separate timetable. A single number sliding down a single line was never the right shape.
Cognitive testing
Your brain is not fully developed at 25
There is no age at which the brain is finished, because its parts peak at wildly different times. One peaks at six and another at twenty-nine.
Cognitive testing
Brain training does not do what it is sold as doing
You get better at the game. That is the whole finding. Transfer to anything you actually do is where the claims run out of evidence.
Cognitive testing
Trivia is better for your memory than re-reading, and the reason is odd
Retrieving something is a better way to learn it than reviewing it. The catch is that retrieval feels like failing and reviewing feels like progress.
Cognitive testing
Every celebrity IQ score you have read is made up
There is no verified IQ score for any famous person you can think of. The numbers are invented, copied, and then cited as though they were records.
Cognitive testing
What a “brain age” score actually measures
The number is a composite of accuracy and speed, mapped onto an age scale. That mapping is a presentation choice, not a measurement.
Cognitive testing
How processing speed changes across adulthood
Speed declines gradually from early adulthood while vocabulary and knowledge keep rising. Most people never notice because the two offset each other.
Archetypes
The twelve recurring character patterns, where they came from, what a type result can honestly tell you, and the shadow hiding inside every strength.
Archetypes
The 12 archetypes test: how it works and how to find yours
The most asked questions about archetype tests, answered without the mysticism and without pretending the result is a measurement.
Archetypes
Your worst habit is your best trait, turned up too far
Every archetype's weakness is its strength at the wrong volume. That makes it findable, predictable, and much easier to catch in the act.
Archetypes
The 12 archetypes: are you the King, the Rebel, or the Lover?
Twelve characters that keep turning up in every story ever told. One of them is how you already behave, and its shadow is your best trait with the volume left up.
Archetypes
Archetypes and the two hemispheres: what the brain actually does
You are not left-brained or right-brained. But there is a real finding about the two halves, and it explains why a type description feels so accurate.
Attention and memory
Why concentration runs out, why some days are harder than others, and what actually helps when it does.
The best evidenced thing for your thinking is not a brain game
Moving has more behind it than anything sold as brain training. The numbers people quote are also doing far less work than they appear to.
Attention and memory
Why you cannot concentrate, and what actually helps
Concentration is not willpower. It is a limited resource with a specific shape, and most advice about it ignores the shape entirely.
Attention and memory
Working memory, and why complex tasks feel harder some days
Working memory is small, shared, and easily spent. Most productivity problems are really working-memory problems wearing a disguise.
Attention and memory
Mental fatigue and attention: four things worth noticing
Fatigue does not reduce attention evenly. It shortens how long you can sustain it, and that shows up in speed before it shows up in accuracy.
How the tests work
The individual tasks: digit span, mental rotation, thinking types. What each one is for and what it can and cannot show.
The advice to stop hedging is built on a real finding and the wrong variable
Cut the padding, keep the hedges that are true. The studies behind stop saying just are real, older than you think, and say something the advice leaves out.
How the tests work
The 8 thinking types, and why most “types of thinker” lists disagree
Three questions, eight answers. Why the lists never agree on how many kinds of thinker there are, and what a type is actually telling you.
How the tests work
Why a mirror image is so hard to reject
b and d are the same shape. So are the figures in a rotation test. Your brain files them together on purpose, and learning to read means partly undoing that.
How the tests work
Mental rotation: the one cognitive skill that reliably improves with practice
Decision time rises in a straight line with how far the figure has been turned. That line is the finding, and it says something odd about what your head is doing.
How the tests work
Digit span: the 60-second memory task, explained
Repeating digits back tests storage. Repeating them backwards tests manipulation. The gap between your two scores is the interesting part.