Last October, my neighbor stretched synthetic cobwebs among the branches of her tree. Against this creepy backdrop, she hung a broomstick and a badly-made female figure, clearly a witch. The sight made me wince.

How did we evolve to find this display lightly amusing? Our forebears did hang women from trees. I imagine the devastation a time-traveler might feel as she realizes people crudely pantomime the appalling circumstances of her death each Halloween.

When my ancestor was accused of witchcraft in 1652, dozens testified. This showed extraordinary involvement when her small town of Northampton, Mass., only consisted of 32 households. How has western culture developed from a witch trial warranting a civic hullabaloo, to no one believing that witches exist?

As with any paradigm shift, many factors came into play. In part, the Enlightenment gave rise to skepticism and an understanding that mischance is simply random. Intellectuals grew concerned that innocent people had been executed.

Another brutal reason: Villages ran out of women to accuse. In some cases, literally.

Two medieval German towns slaughtered their women until only one per town remained. Once the courts exterminated the mutterers, the shamblers

Witches and others outside of society, then they turned to upstanding persons resulting in outrage. The Salem hysteria screeched to a halt when the enchanted girls fingered the governor's wife.

Another reason: population growth. In small European enclaves, everyone bore responsibility for the unfortunates right there at the door. Writer Keith Thomas explored the idea of neighbors confronted with a hungry beggar, whose name and story they well knew -- either they gave of their scanty food and felt resentful, or denied it and felt guilty.

Either of those deeply uncomfortable emotions could lead to a witchcraft accusation. This was especially true if the neighbor stinted and bad luck followed, construed as retaliation.

A horrible double injury, as the suffering wretch went hungry and then possibly died as a condemned witch. As cities grew, teeming with people one did not personally know, responsibility diffused.

And overall, things got better. Who needs a scapegoat when land is safe and food plentiful?

Europe of the Middle Ages lurched out of plague cycles and famines; New England continued fortifying townships that diminished risk of Indian raids and encouraged agriculture and trade. The witchcraft obsession abruptly ceased.

In the United States, the last witch trial took place in 1706. We started celebrating Halloween in the 1800s -- most credit the influx of Irish from the potato famine for importing this initially pagan holiday, Samhain transmogrified.

In the early 1900s, we began wearing costumes. Today the most popular outfit requires dressing as a witch -- either with sexy, gartered legs under the black dress, or sexless in the crone's pointy hat.

Somehow in the 200-year-span from throwing a woman in the river with her thumbs tied to her big toes to see if she innocently sinks or guiltily floats, to gaily donning a stereotyped version of her clothing, Americans lost all belief in, and fear of, witchcraft.

Collective amnesia fogs our minds as we clamp a fake, green, wart-ridden ski slope onto our own noses and cackle maniacally. We've forgotten the woman huddled in a wet dungeon awaiting her murder.

Scholars argue about how many executions occurred during Europe's 400-year holocaust. In The Da Vinci Code, Dan Brown caused controversy when he claimed 5 million. Author John Putnam Demos tracked 139 cases in 17th century New England, excepting Salem's famous trials. (Surprisingly, the courts released almost 30 percent of the defendants.)

A postscript on my ancestor: twice accused, twice acquitted. But certainly the experience scarred her: imprisoned, fighting for her very life, and despised.

When the woman in the next cottage averts her eyes because she believes you love the Devil, you can't exactly run over to borrow a cup of sugar. Nor can you forget that you had a date with a rope (or in Europe, with a stake. England and New England did not burn their witches.)

So how much time must elapse before these horrific tortures ripen enough to be entertaining?

In his novel The Last Witchfinder, James Morrow mocks Salem's annual Haunted Happenings. This month-long "festival" capitalizes on the witch trials where 19 people hanged, one suffocated by rocks piled on his chest, and five perished in prison.

Currently, the Haunting Happenings Website promises "a month of fun for the entire family." To that end, will we someday see the Auschwitz Adventure or the Hiroshima Mushroom Cloud Ride?

In the western world, we battle to imagine someone casting evil spells.

Harder still to imagine testifying, aware the result could be death. Instead of a stuffed, painted pillowcase, my neighbor down the block could've wanted me in her tree swinging.