Science probes mysteries of the past in this series, including “Witches' Curse,” a new look at the notorious Salem witch hunts of 1692. The “witches” (19 of whom were hanged) were accused of causing hallucinations and convulsions in eight Salem girls, who testified against them. In later years, it was assumed the witnesses were lying. But behaviorist Linnda Caporael suggests that they were “tripping” on the bread they must have eaten. Liev Schreiber narrates.