My identical twin, Julia, and I recently went to an art gallery talk about Diane Arbus’ famous photograph, Identical Twins, Roselle, N.J. The original 1967 print was there on the wall: a pair of matching young girls, dressed in black dresses with stiff white collars, eyeballed us from just over the curator’s shoulder.

The twin on the left – the one I identify with – looks retracted: her eyes are slightly hooded, her mouth tense. The one on the right – clearly, my sister – is bright-eyed, with a half-smile playing across her lips.

“Who finds this creepy?” the curator asked the audience.

A detail of the Diane Arbus portrait “Identical twins, Roselle, N.J.” 1967.Credit: Diane Arbus

Hands flew up all around.

“That’s part of the enduring fascination of this picture,” our informant continued. “There’s just something creepy about twins.”

Julia and I exchanged identical eye rolls.

“Creepy to who?” I whispered.

I mean, sure, the dark hair and outfits in Arbus’ photo emit a Wednesday Addams vibe. But to me and Julia – and, I suspect, to many of our tribe – the twins themselves look totally normal. Our family photo albums are filled with childhood pics of us obediently standing in front of walls sporting identical outfits. It’s photos of single children that strike us twins as disturbing. Where’s the other one disappeared to?

Arbus’ photo inspired the definitely creepy twins in Stanley Kubrick’s The Shining. And those twins in turn are part of a long tradition of representing twinhood as uncanny, sinister, or dangerous. Sometimes, as in Arbus’ picture, the effect is mild: the twins appear titillatingly mysterious, just over the edge of the familiar. Other times, they’ve fallen fully off the cliff. Edgar Allen Poe’s short story, The Fall of the House of Usher, stars a pair of twins who become mutually obsessed and die in each other’s arms, just before their gothic manor cracks in two and sinks into the family lake. Or take the recent remake of David Cronenberg’s film, Dead Ringers, in which twins – one of them, again, reserved, one bright-eyed, both played by Rachel Weisz – end up, to put it mildly, “with serious mental health issues” and drenched in blood.