David Carmel, a cognitive neuroscientist at New York University, suggested that even when the girls deliver right answers, the phenomenon could be explained by something other than a neural bridge. “If they’re really close, through minute movements that one makes — maybe a typical movement her sister cannot see, but can feel — the other sister intuits the association. Maybe she associates her sister’s reaction with a robin they once liked, not a turkey.” The connection then might be scientifically mundane, but a marvel nonetheless to the casual observer.

Epistemic caution recommended.