TULSA, Okla. - Oklahoma authorities said they caught a suspected porch pirate that donned "an unusual and questionably effective mask." He was seen wearing women's underwear over his face. Tulsa ...

New research from York University shows wearing a mask can impact the ability to recognize other people, even if those being viewed have nothing covering their face. Top News .

That's especially true when there are many people wearing the same masks, and a masked rock-thrower (for instance) can feel safe that it will be hard to identify him among the other mask-wearers.

Overall, they estimate, mask-wearing accounts for about 4 percent of the variance in deviant behavior they observed, when comparing those wearing masks to those not wearing them.