Aug 08 2011
Remember that famous scene from Star Trek II – Kirk and Khan are engaged in a classic submarine-style fight in a large gas cloud. Spock has analyzed Khan’s tactics and deduced that while Khan is genetically engineered to be brilliant, he is inexperienced. “He’s thinking two-dimensionally,” concludes Spock. Next we see the Enterprise rise up out of the depths of the cloud (relatively speaking) and get a sneak attack on Khan’s ship from behind.
While very dramatic, I always wondered how realistic that scene was. Is there a naive tendency to think two-dimensionally, even when flying out in space? Well, new evidence suggests that perhaps there is.
Neuroscientists have published a study in rats in which they look at the activation of two specialized types of neurons, grid cells and place cells, in rat brains as they navigate a three-dimensional space.
For background, place cells are special neurons that fire in relation to an object’s location. Grid cells fire in relation to an object’s distance. With direction and distance our brains can map where stuff is in relation to us and other stuff. The research, however, has focused on two-dimensional location. Hayman and colleagues therefore decided to study place and grid cells in 3D apparatuses – a climbing wall and a vertical helix.
What they found was that the grid and place cells functioned as predicted in the horizontal plane. However, the grid cells (the ones that encode distance) fired very little or not at all in response to vertical distance. In other words – rat brains are good at mapping how far something is, but not how high it is.
Of course, this is just one study in rats, so we need to explore this issue further, with different mammals (hopefully eventually humans) and in different experimental setups. The experimenters infer that what they found is generalizable to the mammalian brain. This is not unreasonable, but I wonder if primates who were adapted to living in trees developed more of a three-dimensional mental map. If so, did humans retain that enhanced vertical mapping, or did our ancestors lose it on the planes of Africa?
If we assume that the results of this study apply to humans, does that make sense in terms of our own experience. Obviously, we can think three-dimensionally – we can think about how high something is. But we may still retain a horizontal bias. It does seem as if we are more comfortable with the horizontal plane than the vertical dimension. The difference may be between having dedicated hardware that is very good at horizontal reasoning, and having to use more general cortical resources to transpose our spatial reasoning into the vertical dimension. This would give us the ability to map in 3D, but just better and more effortlessly in the horizontal plane.
A horizontal bias has been detected before and published in the psychological literature. Hansen and Essock, for example, found that we process horizontal nature scenes best, then vertical scenes, and least well oblique. This makes sense as these orientations match what we would most encounter in nature. Schipper et al also found a horizontal bias in contour detection. Subjects could still detect contours (in this case ellipses) in the vertical direction, but it took a bit longer, suggesting more processing was required. Durgin et al also found a horizontal bias in our ability to judge distance. There are other studies as well. This phenomenon is referred to as perception anisotropy – a difference in how we perceive the horizontal vs vertical dimension.
It therefore seems that the new study is confirming and explaining the underlying neurological basis for the previously documented horizontal perception bias, and that this bias does extend to humans.
So it does make sense that Khan would have defaulted to the natural human horizontal bias in how we map and think about the world around us. Our brains can deal with the vertical dimension, obviously, but it takes a bit more effort and perhaps training. I imagine that Starfleet has a class that’s titled: “Tactical reasoning in a three-dimensional arena – do not neglect the vertical,” or perhaps, “Attacking on the oblique – how to exploit your opponent’s monkey brains.” Perhaps they even have to adjust for the varying perception biases of different species. Maybe Romulans are better at reasoning in the vertical plane, and Klingons have an oblique bias.
Probably, though, any species that evolved mainly on the surface of a planet would have a similar horizontal bias. That’s where most of the interesting stuff is happening.
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