A computer can tell with 78 percent accuracy when someone is thinking about a hammer and not pliers.

Crime investigators always have their ears open for information only a perpetrator could know—where a gun used in a murder was stashed, perhaps, or what wounds a stabbing inflicted. So imagine a detective asking a suspect about a killing, describing the crime scene to get the suspect to visualize the attack. The detective is careful not to mention the murder weapon. Once the suspect has conjured up the scene, the detective asks him to envision the weapon. Pay dirt: his pattern of brain activity screams "hammer" as loud and clear as if he had blurted it out.