There is no better way to attract reports of the paranormal than to write a story casting doubt on it, and attract them I did. Besides the usual ghost sightings, my favorite was from a nice man in Florida who told me about his wonderful typewriter (note: not a word processor): he would type a few letters of a word and the machine would fill in the rest, apparently having read his thoughts.

Make of that what you will. More interesting, to my mind, was a note from Michael Shermer of the Skeptics Society, who pointed me to his column in the December issue of Scientific American. There, he explores what he calls “patternicity,” the tendency of the human brain to “find meaningful patterns in meaningless noise,” as he puts it, as shown in our tendency to “see faces in nature, interpret window stains as human figures, hear voices in random sounds generated by electronic devices or . . . see the Virgin Mary on the side of a building”—or in a potato chip, as I noted in the story.

Evolution favored humans who were “most successful at finding patterns,” Shermer writes, a process called associative learning that “is fundamental to all animal behavior. . . . Unfortunately, we did not evolve a Baloney Detection Network in the brain to distinguish between true and false patterns.” Hence those Mary sightings.

Shermer cites a fascinating paper to be published in January in the journal Proceedings of the Royal Society B. In it, Kevin Foster of Harvard and Hanna Kokko of the University of Helsinki show that when it costs less to believe in a pattern or connection that isn’t real (believing that a noise in the grass is a hungry tiger when it is only the wind) than to fail to make a connection that is real (ascribing the noise to the wind when it is actually a tiger) people tend to err on the side of patternicity. If our ancestors had erred in the other direction—“oh, that’s usually just wind, nothing to worry about”—they would not have been our ancestors because they would have been eliminated from the gene pool.