The Surprising Relativism of the Brain’s GPS
Adithya Rajagopalan
Adithya Rajagopalan
Quote:Physics grappled with the question of whether space is absolute or relative for centuries, before deciding in favor of relativity. But, it is only in recent years that the brain sciences have begun to discuss a parallel set of questions. For many years now, absolute space has ruled neuroscience. In the visual system, for example, it has long been assumed that there are two channels of information flow.4 The first is the “what” channel, carrying information about the identity of objects that an animal sees. The second is the “where” channel, containing information about the absolute position of these objects. It was believed that the “what” channel contained no positional information at all. However, recent work has shown that while no information about the absolute position of an object is present in this channel, there is relative position information.5,6 This relative positional information is likely to be very important for object recognition.
Findings like this have provided a foothold for the idea that relative information can be important to the brain. But it has been the recent marriage of neuroscience with the fields of computer science and artificial intelligence that have really strengthened this perspective. Work at this interface has shown that a brain that uses an absolute, invariant model of the world to model and negotiate changing environments requires more computational resources than one that uses relative information. Understanding when and where our brains use relative and absolute information could provide insights into the working, flexibility, and speed of its subsystems and into our own behaviors. The hippocampus, in particular, could be one of the first waypoints in this debate.
'Historically, we may regard materialism as a system of dogma set up to combat orthodox dogma...Accordingly we find that, as ancient orthodoxies disintegrate, materialism more and more gives way to scepticism.'
- Bertrand Russell
- Bertrand Russell