To the casual observer, trading fours looks a lot like musical instruments engaged in conversation – individual viewpoints and expression, in sync thanks to similar ideas, constructed with no forethought beyond a shared concept and maintained simply through the experience and knowledge of having a vocabulary and putting it to use on the fly to respond to new inputs.

The drive to connect and communicate is in fact so strong it exists even in the absence of the communication methods most of us know – it’s a drive we can’t hold in any more than the instinct to eat or sleep.

As our understanding of the way the brain works deepens, such technology will shine even more light onto many cognitive abilities and phenomena, including our seemingly-immutable sense of self.