Monday on "Nightly News" we told viewers about a cognitive self-assessment test developed by researchers at Ohio State University that can help you determine your ...

It may seem counterintuitive at first, but using a dull blade is actually more dangerous than using a knife with a sharpened blade. The reason for this is that a dull blade is more likely to slip off ...

How observant are you? The jungle is dense, and the camouflage is perfect. A tiger is lurking and the clock is ticking—can you locate it in just 8 seconds? Optical illusions have long been used to ...

Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content. (The four forms represent four different versions of the test -- you can choose whichever one you'd ...