Grey Matter
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.
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.