Vision is a 'Reflex'

kernkopje writes "A recently publicized book by two neurobiologists at Duke University introduces an interesting emperical theory on vision. Rather than postulating a visual system that generates a picture of what actually exists in front of the viewer, they theorize that evolution, as well as life experience, has created a visual system in which perceptions represent what a given visual stimulus has typically signified in the past. Admiring the view from a high building, staring at a beautiful woman, shapes, colors, textures, it's basically all the same knee-jerk response... The news release is here, read more about the concept here. Their lab work & results can be found here."

Comments

To simplify

[dpilot]

Vision is whatever helped our ancestors survive. If that were a pure image of objective reality, that would be how we see. If it were an interpretation based on past events, and that that predator is going to eat me and deprive me of my right of reproduction if I don't move, pronto, then that would be how we see.

How well this fits into modern life and jury trials is another issue.

Re:Syntax vs Semantics

[SmileyBen]

Sure. You're absolutely right. A computer can tell us that the wavelengths of light hitting two sensors are the same. If what these researchers are saying is 'Isn't it bizarre that that doesn't happen... that we can have illusions?' then the simple answer is that if that was what eyes were trying to do (as much as they're trying to do anything) that would be a problem, but they're not.

Frequently we don't see two instances of the same wavelengths of light as the same colour, but that's because there are obvious evolutionary advantages of not seeing the same 'colour' as the same colour quale (the 'mental image of the colour'). Such as when there are red berries amongst green leaves, where it is advantageous for the red to look more red and the green to look more green, or such as edge detection, where if you have alternating strips of light and dark the light seems lighter and the dark seems darker where they meet, emphasising the edge.

I assumed that everyone had accepted that these were the products of evolution, and didn't think that illusions were illusions in a pejorative sense (i.e. not defects) - but it seems like these guys are presenting this as something new and exciting, and I just can't see how...

Duke Magazine need a course in perception

[exp(pi*sqrt(163))]

Didn't anyone tell them that having a vertical grey bar through black text on a white background is painful to read? It seems any idiot can be hired to do graphic design these days.

This article is bullshit.

[t]

If you examine figure 4, the rubix cube, with gimp, then the so called brown squares are NOT the same color.

Compare this to an illusion that actualy passes this test: checkershadow

The question is why make a bogus illusion when a good ones exist? NIH? (Or perhaps they don't want to support MIT?) Is all their "research" of this quality?

The reason why the brain confuses colors and such is because it quite sensibly corrects for shadows. It very sophisticatedly determines the light source, and compensates for it. Why is that so hard to grasp?

Re:Seems like common sense to me

[MrGrendel]

Not only does it seem like common sense, but it isn't even a new idea in neurobiology. The only thing that might be new about this is attaching the label "reflex" to it. Evolutionary psychologists and vision researchers have been talking about this stuff for at least the last decade, and probably longer. There is nothing new about the idea that visual illusions exist because visual stimuli are ambiguous and the brain interprets them according to the most likely (most frequent) source. I hope that this is just a case of an uninformed PR rep oversimplifying their theory.

The article also misrepresented some of the research that has gone on in the past. Visual circuits have been traced and analyzed in an effort to learn how the brain sees, not what it sees (which is what their theory is really about). Researchers want to know how the brain is able to detect motion against a noisy background, how people are able to represent 3-D objects in their heads, how the brain assembles thousands of visual cues into a coherent representation of the world. (Some brain injuries disrupt these functions -- there are people who cannot see motion - moving objects are percieved as stationary objects that jump around discontinuously - some people are not able to construct an image of everything that their eyes detect - they can only see one or two distinct objects at a time). The observation that vision is a kind of reflex does not even begin to answer questions about how the visual system works. I don't see how they can call it a theory of vision if it doesn't offer any explanation for fundamental problems that visual systems must solve.

Also the comment about detecting the source of sounds is incorrect. The neural circuit that takes care of that has been known for a long time. It localizes sounds by comparing phase differences between sounds arriving at each ear. In fact, it has even been demonstrated that the circuit trains itself to do this task (a great example of how Hebbian learning works).

I'll give them the benefit of the doubt and assume that the person who wrote the article didn't understand a bit of their theory.

"Reflex" is the wrong word

[Tardigrade]

As many physical reflexes can be short-circuited much more easily than the described visual reflexes.