Via Mind Hacks, a story in the New York Times about twins conjoined at the head in such a way that they share brain matter and possibly consciousness.

Twins joined at the head — the medical term is craniopagus — are one in 2.5 million, of which only a fraction survive. The way the girls’ brains formed beneath the surface of their fused skulls, however, makes them beyond rare: their neural anatomy is unique, at least in the annals of recorded scientific literature. Their brain images reveal what looks like an attenuated line stretching between the two organs, a piece of anatomy their neurosurgeon, Douglas Cochrane of British Columbia Children’s Hospital, has called a thalamic bridge, because he believes it links the thalamus of one girl to the thalamus of her sister. The thalamus is a kind of switchboard, a two-lobed organ that filters most sensory input and has long been thought to be essential in the neural loops that create consciousness. Because the thalamus functions as a relay station, the girls’ doctors believe it is entirely possible that the sensory input that one girl receives could somehow cross that bridge into the brain of the other. One girl drinks, another girl feels it.

  1. The story is very interesting and moving.  Worth a read.
  2. I would like to see them play Rock-Scissors-Paper.
  3. More generally, experimental game theory suffers from a mutliple-hypothesis problem.  We assume rationality, and knowledge of the others’ strategy. Departures from theoretical predictions could come from violations of either of these two.  The twins present a unique control.