Human Eyes Are Wired Backwards

https://theconversation.com/look-your-eyes-are-wired-backwards-heres-why-38319

56 47 11 years ago

mirimir• 11 years ago

Very cool! I've often wondered about that.

walterbell• 11 years ago

From the article, "..we also noticed something rather curious: the colours that best passed through the glial cells were green to red, which the eye needs most for daytime vision. The eye usually receives too much blue – and thus has fewer blue-sensitive cones."

From another article on the same site, https://theconversation.com/a-dark-night-is-good-for-your-he...

"Light from the Sun is strong in blue, short wavelength light ..when it comes in the evening or during the night, it fools the body into thinking it’s daytime. We now know that this bright blue light has the strongest effect on lowering melatonin during the night. Your tablet, phone, computer or compact fluorescent lamp (CFL) all emit this kind of blue light."

bjwbell• 11 years ago

That's why I take melatonin tablets ~20min before bed. It's one of the best known methods to improve your sleep and overall well being.

http://www.gwern.net/Melatonin

ars• 11 years ago

This has always been listed as a "proof" that God did not create people because why would he mess up this design?

cbd19842• 11 years ago

Which isn't how this works, philosophically speaking.

The best argument for evolution isn't a listing of how badly-designed we are, it's a simple observation that the one simple principle of natural selection through modified descent suffices to explain us. We don't need any other hypothesis. Therefore, the principle of parsimony kicks in and other, more complicated, hypotheses are ruled out. Not absolutely, but fairly strongly, at least until we find things that our current hypothesis cannot explain, which hasn't happened yet.

StuffMaster• 11 years ago

That is a most excellent explanation.

alphapapa3• 11 years ago

The idea that, since a certain explanation appears to suffice, it must therefore be the truth, is an obvious fallacy.

Besides that, there are many people who disagree that it suffices to explain us.

sorokod3• 11 years ago

More of a counter to the intelligent design argument. Well, at least to the intelligent part. Proponents of intelligent design tend to be religious, and having difficulty accepting a fallible deity

vidarh• 11 years ago

This is how I use it in debates where intelligent design proponents will on top of the complexity argument tend to use examples of how fantastic everything is as evidence of design. A blatant example of something that seems so in your face obviously flawed tends to throw them.

It's also useful because the complexity of the eye is often used as an argument for ID on the assumption that an incomplete eye would be useless, but for the eye we do have a long range of intermediate stages that would provide useful levels of sight, and we can show a long range of variations over eyes in existing organisms.

alphapapa3• 11 years ago

If the universe and everything in it--including ourselves--was created by an intelligent creator being, then we would be in no place to judge whether such a being was fallible. The very concept of what constitutes an error would be defined by the being itself.

dekhn3• 11 years ago

I actually really enjoy watching Dawkins' argument against intelligent design get shredded by basic modelling. Not that I believe in intelligent design, but because Dawkins is a smug bastard who wove an entire argument on a fallacious assumption.

osn2• 11 years ago

Link?

alphapapa3• 11 years ago

Your question is so loaded it is bursting at the seams.

What qualifies as "messed up?" Having a design that appears suboptimal?

What would be not-messed-up, or what would be perfect? Having vision equivalent to a hawk? A telescope?

Why do you assume a creator being would necessarily choose to make perfect things? What if creating perfect things was not the creator's purpose? What if its creation was perfect for its intended purpose?

If a supernatural being exists and created the universe and us, it's ludicrous to think that we could put ourselves in its place and say, "Well, obviously he should have done it like this instead, therefore he doesn't exist."

We can't even understand how our own brain works, but some of us think that we are smarter than God. Regardless of what you believe about the existence of a supernatural creator, it's obvious that we would be inferior to such a being.

Veedrac• 11 years ago

We can't even understand how our own brain works, but some of us think that we are smarter than God.

If you refuse us the right to make any claims about a god, you also refuse the right to make any arguments for it.

Obviously, ars was talking about the gods mentioned in popular religious texts. These texts make very specific claims about what their gods are and do.

Arguing about arbitrary gods is, of course, largely fruitless. However, belief in them is equally fruitless.

dribnet• 11 years ago

Article fails to mention: the eyes of the squid and octopus are very similar to ours in overall structure, but are not "wired backwards". So it seems that any explanation of why backwards is actually "vision-enhancing" is incomplete unless it also explains why it would not be enhancing for the squid. (though perhaps a justification could exist based on different wavelengths and lighting conditions underwater)

pygy_• 11 years ago

The vertebrate eye evolved under water as well (in fish).

ozim• 11 years ago

When I read this, I felt anxious about amount of time it takes to evolve eyes compared to my lifespan. Feeling so small.

meric• 11 years ago

I hope my cells don't evolve during my lifespan, because if they do it means I have cancer.

schiffern2• 11 years ago

Don't worry, the cancer will then evolve politicians, who will hail that evolution as an unprecedented innovation, claiming that only further innovation and economic growth will solve cancer's problems. They'll point out how cancer cells are special compared to other cells: how they've conquered the natural causes of death and overcome many logistical obstacles to build a complex high-density society with a rich history and lots of diversity.

Intrepid cells (no doubt sick of the crowding in their native tumor) will sometimes set out to explore and colonize the unruly wild parts of the body. It will be hard, but a few of those colonists will succeed in establishing far-flung outposts.

Surely there will be a few environmentalist cancer cells that oppose the "development" of the body, but the common perception among cancer cells will likely be that those cells are just standing in the way of progress, and anyway that the body is so vast that a single cancer cell can't do very much to effect the outcome.

/remove tongue from cheek ;)

ggreer• 11 years ago

Please take the article with a huge grain of salt. Hundreds of millions of years ago, vertebrate eyes originally evolved backwards. Evolution hill-climbs, so the backwardness (and ensuing disadvantages like the blind spot) can never be fixed. Tricks with glial cells are nature making the best of a bad deal.

Also, the author's ignorance of biology concerns me. In one comment, he thought that color-blind people saw in grayscale. If you know how human cone and rod cells are set up, such an idea seems preposterous.

BoardsOfCanada• 11 years ago

Exactly, it feels very strange that anyone would find it "rather curious" that the eye has evolved toward a local optimum. And moving the wiring out of the light's path would allow for even more of this concentration mechanism in front of the retina.

brudgers• 11 years ago

The picture of the guinea pig says a lot about the intellectual heft of the article...fluffy and not addressing the scientific reality. I'm not a member of PETA, but thinking about the messy reality of experiments on guinea pig eyes is not something I take as being without karmic costs. Grass, sunshine and a bowl of kibble are not what laboratory experiments on animals conjure to my mind.

wyager• 11 years ago

Evolution hill-climbs, so the backwardness (and ensuing disadvantages like the blind spot) can never be fixed.

Well, there's some randomness in there too. I'm sure genetic local maxima get busted sometimes.

Retra3• 11 years ago

The problem with randomness is that it is overwhelmingly likely to produce worse performance, not better. So much so, that it is practically impossible to improve through random effects.

mtooth• 11 years ago

You make a good point regarding the author's understanding of color blindness, however gray-scale vision absolutely does exist in humans, albeit in a much smaller proportion of the population than common red-green colorblindness:

https://en.wikipedia.org/wiki/Achromatopsia

sidcool• 11 years ago

The human eye has always made me wonder of the sheer complexity of the human body. It's an amazing epitome of evolutionary success...

zzalpha2• 11 years ago

Epitome? Nah. The human body is flawed in any number of ways. This article has some interesting notable examples:

http://www.smithsonianmag.com/science-nature/the-top-ten-dai...

Humans are optimized in some very specific ways, but at the expense of some serious downsides.

As a related aside, I think its this misunderstanding that confuses people into preferring creationism. If one holds the anthropocentric view that humans are the peak of biological evolution (itself a meaningless concept... Evolution is about fitness, it's not directional), believing in creationism is a lot more understandable.

vinceguidry2• 11 years ago

From the article:

One of the reasons it is so difficult to stop hiccupping is that the entire process is controlled by a part of our brain that evolved long before consciousness, and so try as you might, you cannot think hiccups away.

I can. Reliably. I concentrate in the general direction of my diaphragm, and often times I can stop the third hiccup before it happens. I have to wait until the second hiccup before I know I'll have to use the technique. The only time I can't do it is when I've been drinking, which is, coincidentally, when I get them the most. I can't concentrate the way I need to, it's like that part of my brain is shut off.

teddyh• 11 years ago

The human body is flawed in any number of ways.

Yes; “This project is doomed.”:

http://threepanelsoul.com/2010/07/05/on-design-by-committee/

schiffern2• 11 years ago

It's an amazing epitome of evolutionary success...

And so is every other species. We've all been evolving together on this planet for the same amount of time.

This is why driving species to extinction is so spectacularly stupid — it squanders our collective legacy of genetic information, hard-won over billions of years of struggle. How many discoveries like this will never be made because we destroyed the species? Worse, how many useful functional species are we depriving ourselves of (including functions we don't even know we need yet)?

tachyonbeam• 11 years ago

I've been making the argument that we should be sequencing the DNA of endangered species. Preserve some of that legacy digitally before it's too late.

sorokod3• 11 years ago

Related: "Why we have blind spots - and how to see the blood vessels inside your own eye"

https://www.youtube.com/watch?v=L_W-IXqoxHA

Balgair• 11 years ago

That the retina has the receptive cells under the 'cabling' is not novel and is well studied. The authors here introduce the study of the glial 'supporter' cells and their refractive indices as wave guides for light to the receptive cells. This is actually pretty cool! Most neuroscience and physiology hasn't considered this as an advantage before, just a quirk of evolution that the eye is 'backwards'. Also, for other readers out there, the structure of the retina may be a good reference (https://en.wikipedia.org/wiki/Retina). To note: there are regions of the retina that differ in cone/rod concentration. The Fovea, the center of our vision, is entirely cones, while the outside is almost entirely rods. Also, the receptive cells have many synapses where data is processed before it going to the optic nerve. The retina acts similar to an FPGA in that the whole data set is compressed before transfer.

Human Eyes Are Wired Backwards

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