Stimulating the brain with electrical currents is exploratory technology. But people are making and buying devices that do that for use at home — and interest rises around exam time.

Michigan State University engineers tried 3-D-printed fingertips and special conductive replicas of the victim's fingerprints to crack the biometric lock on his Samsung Galaxy phone.

Researchers fed a program 600 hours of videos and TV shows to see if it could learn about and predict human interactions — hugs, kisses, high-fives and handshakes. It was right nearly half the time.