Our built-in human "like" detector...

It turns out we all have a built-in like detector – it’s a yawn. Yawns are contagious and a recent study found that the sooner someone catches your yawn, the more connected they feel to you. If you’d like to test out the theory, here’s how it works. The better you know someone, the sooner they’ll catch your yawn. Family members usually react within a minute. A good friend will probably yawn back in about 2 minutes. Casual acquaintances should return your yawn within a 3 minute window. If someone you’re not already connected to reacts to your yawn – there’s a good chance they are really tuned in to you and you’re probably very compatible.

If you strike out with your test subject and can’t evoke a yawn – there’s still hope. It could be a sign that the two of you need to spend a little more quality time together. Once you’re in sync, the yawning will ensue.

Source: Elisabetta Palagi, PhD, primatologist and anthropologist, Natural History Museum, University of Pisa, Italy