Which teal line is longer, A or B?

Same length! Both teal lines are exactly 4 inches.
The five games from NeuroNight SF, each showing a real principle of how your brain works. Take a guess, then reveal the answer. Better yet, try them on a friend.
Five cards from the night. Look closely, make your guess, then reveal.

Same length! Both teal lines are exactly 4 inches.

They're the same size.

No. Every grey line is perfectly straight and parallel.

There is no white triangle: just three cut discs and a broken outline.

Slower than reading the words, right?
Most of these you can try at home with a friend.
Hide your real hand, put a rubber hand in view, and have a friend stroke both at exactly the same time.
Try it at home: hide one hand behind a book, put a glove or fake hand in front of you, and have a friend stroke both at the same time with two paintbrushes.
A friend drops a ruler between your fingers without warning. Catch it, then read your reaction time off the chart. Then try it again while multitasking.
Caught at 15 cm ≈ 0.17 s, at 20 cm ≈ 0.20 s, at 30 cm ≈ 0.25 s. Then do it again while counting down from 100 out loud.
The prism goggles we had at NeuroNight SF flipped everything upside down! Trying to shake hands, catch, or even point at something was a major challenge. Want to try it at home? You can buy upside-down goggles on Amazon.
In a classic 1890s experiment, a psychologist wore inverting lenses for 8 days and gradually adapted.
Hold your nose, eat a jelly bean, then let go.
Try it at home with any jelly bean or a piece of fruit. Can a friend guess the flavor with their nose held?