How Mammalian Brains Map in 3D
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.
“or did our ancestors lose it on the planes of Africa?”
Excellent double entendre, Dr. Novella!
I bet playing Descent will improve your ability to map in 3D.
So would playing baseball.
This post reminds me of a comment made by a bad buy on some drama show I saw many years ago. He opined that a good place to hide one’s self or an item was up, as on a shelf, the top of furniture, etc, because “people don’t look up.” Since that time, I have noticed that when searching for something, my tendency is to not look up unless I remind myself of the bad guy’s observation.
It would be very interesting to compare the brains of skilled pilots, especially fighter pilots and aerobatics competitors, with groundlings’ brains — and those of Air Force cadets before flight training. Is there an innate talent for three-dimensional thinking? (In which case air forces should recruit for it.) Or is it something which can be developed?
I doubt most pilots use much 3D skill – you are highly reliant on your instruments or seeing the horizon (and the enemy), and partly on feeling the acceleration and response of your plane. Maybe an acrobatic pilot or fighter pilot would have something to say … At any rate, many of the skills you use to maneuver on the ground are almost entirely useless in the air because there are very few points of reference.
(I am not a pilot, but…) The other thing about aerial combat in a planetary atmosphere is that while you have to deal with vertical, the horizontal direction is still the “dominant” direction, followed by obliques. That wouldn’t be the case in space, where up and down are completely subjective. That was a plot point in Orson Scott Card’s Ender’s Game, where one of the protagonist’s big strengths was that he was better at thinking in 3D than most people.
I wonder what sorts of problems that the 1st aerial combat pilots encountered along these lines.
Losing awareness of the horizon was one of the biggest problems. Also, pulling any acrobatic maneuvers hoping to avoid the enemy was likely to starve your engine of fuel and make you crash. Planes with bigger engines could go too high and the pilot was starved of oxygen. I don’t think 3D navigation as described in the papers mentioned came into things much unless perhaps you were pulling stunts intended to make your pursuer lose control of his aircraft.
I’ve a feeling you guys do not read as many old air combat stories as I do. :-)
Certainly in WWI, WWII, Korea and Vietnam, pilots really did have to think in three dimension. The human brain is amazingly “trainable”, and these pilots thought and behaved that way:
A fascinating tale of air combat here – http://www.elknet.pl/acestory/anderson/anderson.htm (Halfway down the page – under “He Was Someone Who Was Trying to Kill Me, Is All”. Primarily fought in the vertical. Morbidly fascinating too as it shows that sometimes air combat is like a chess game, in that it comes to a point where the protagonists both realise someone has made a wrong move, and the ending is now almost inevitable.
Or read about Duke Cunningham’s combat in Vietnam, and “vertical rolling scissors manoeuvres” (that even sounds 3 dimensional!)
I’m not sure it all applies as much in today’s air to air combat planes with long range guided missiles and computer screen targeting, but ground attack and helicopter pilots presumably should be thinking in three dimensions lest they become part of the landscape.
And sports-wise – think of the X-games motorcycle stunts, or ski and snowboard trick, skate and BMX riders on huge ramps.
#7 LovleAnjel makes a valid point – how trained were those rat’s brains?
Though, thinking further, only very few pilots become excellent combat pilots – perhaps a limiting factor is our limited ability to cope with a 3D situation?
I’m betting squirrels have some fine 3-D mapping skills, as do most birds. Using lab rats which have spent generations living in 16″x8″x8″ boxes are maybe not the best animal model for this.
On the other hand, starting with lab rats could make a very useful baseline to compare squirrel or bird results against.
Plus squirrels and birds are USDA-regulated and rats are not.
You can use Star Trek (and most movie/TV sci-fi) to point out the “horizontal bias” another way — just look at how space battles always have the ships “right side up” even though in reality there is no particular reason to do so (and potential tactical reasons NOT to do so). The producers do so because the VIEWER would find ships being twisted every which way and flying in all directions (rather than all on the same general plane) confusing or at least aesthetically displeasing.
I mean, come on, the Enterprise would look “wrong” if you always saw it flying “sideways” or “upside down.” That shows you our “horizontal bias” right there. :-)
I’m not sure it shows a horizontal bias, but rather a gravitaional bias. So when there is no up or down in space, what happens to our spacial processing? Does it alter, or falter?
The VIEWER isn’t experiencing a lack of gravity. They just want everything to be facing “up” and moving across the same “level” so that it looks “right.” That is, they want everything on the same plane of movement. Having ships coming in at odd angles from one another and facing other directions than “up” violates our expectations.
Yes, of course. And what is the basis of that expectation? Is it a completely view-orientated bias ie we’re more aware of things that are in the same plane of view as the axis between our eyes, or is there also a second gravitatonal component on top of that?
Coming from a country where baseball is not popular it was very confusing to me the references about * top and bottom of the inning*. Didn’t time moves left to right? And in this new * vertical time scale* does time moves up or down? :) my own cultural horizontal bias.