Pupil dilation provides a physiological readout of information gain during the brain's internal process of belief updating in the context of associative learning.

Experts disagree on who needs it and when. Here’s what the evidence suggests. By Michelle Crouch Perhaps the most unpleasant part of an eye exam is when the doctor squeezes in the dreaded drops to ...

Mydriasis is the medical term for an unusual dilation or widening of the pupils. There are various causes of this fixed dilation of the pupils. Normally, a person’s pupils dilate when the light is dim ...

We’re all too familiar with the inexorable march of time, but why exactly it flows in one direction remains a mystery of physics. A few years ago Australian physicist Joan Vaccaro proposed a new ...

Breakthroughs, discoveries, and DIY tips sent every weekday. Terms of Service and Privacy Policy. For most of human history, we kept time by Earth’s place in space ...

Time dilation is possibly the weirdest part of Einstein’s Theory of Special Relativity. According to time dilation, the faster you travel, the slower your time moves. But why does this happen? It’s ...

Einstein realized that time is relative and passes at different rates for different people. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Time ...