Evolutionary psychology: evolving three eyed monsters

It is worth saying, though tautologically true, that evolution can't do what evolution can't do, and that the genetic code for new structures and functions has to be combinatorially accessible to the evolving genome.

It is worth adding that evolution can't do most of the things that evolution could do either. At least not in one instance like that which we see.

Big rearrangements at a single step leave you with disabled individuals. That's how we didn't evolve the third eye, too.

It is certainly possible to evolve a third eye on back of the head, but that takes several steps going in different direction, a very huge number of generations, and it most certainly is extremely unlikely in such brief timeframe.

One shouldn't invoke that sort of change unless one first demonstrates that this extremely unlikely path is positively the most likely way in which nested syntax can arise. They didn't demonstrate so; they just have very strong prejudice; that's what rationalizations are.

The neuroplasticity being what it is, it appears we don't need conjunctions of multiple highly unlikely events such as this as explanation for the nested syntax.

Gazelle can afford to move it's eyes to sides of the head (not being a predator), the fly has near omni-directional vision.

The predators, however, have a problem - they can't move the eyes to sides of the head, because that will lose the sharp binocular vision they need to stalk the prey. So it is predatory species that would benefit the most from a rear view eye. The chameleon evolved very peculiar eyes, but that's the only solution the predatory vertebrates got.

The spookfish evolved rear view mirrors that it uses to look down and up at same time. As well, there is parietal eye, but this one is very ancient and traces all the way back to time when ancestors of those animals were more transparent and it was a straightforward adaptation to add light sensitivity to some cells in the brain.

It is extremely difficult to evolve eye on back of the head. It's rare dumb luck, it takes a lot of generations, and existing eyes don't end up duplicated (except in insects and spiders etc which apparently have more flexible coding for eyes; but even in those this kind of thing doesn't happen overnight).

The point of the example is that it is not enough to show that something is advantageous, to show that it is possible to evolve. Furthermore, thanks for bringing up the gazelles - that serves as an example of how evolution really solves the rear-view problem. It doesn't create new photosensitive modules, or replicate existing ones. It just moves the eyes to sides of the head. Keep in mind that eyes, developmentally, are modules of the brain.

The evolutionary psychologists don't take that empirical knowledge of the ways of evolution into account in any way; that's why i would say they are misusing word 'evolution' to mean 'magic'; the word evolution ought to encompass our knowledge of how evolution works, whereas the magic can do anything.

Prey animals generally have their eyes on the sides of their heads, which do a good job of covering all directions. And eyes are expensive -- they need a lot of brain.

The flatfish has one eye that moves to the other side of its head.

Edit: to clarify: two eyes, one of which moves to the other side of its head as it grows. Richard Dawkins is fond of this example, using it in The Blind Watchmaker and The Greatest Show On Earth.

Flies have compound eyes which allow nearly omnidirectional vision. Evolving a new eye when you've already got hair in the way is probably hard, since it would get in the way of a simple light sensitive patch as a starting point, and even if a specimen did mutate one it would probably offer a very weak advantage compared in a species that already has fully developed binocular vision and the ability to turn its head.

Some species have developed additional eyes evolving independently from their original sets though

It's not about size of the change, it's about the complexity of the change. Increasing the brain size by four times is not a very complex change; some minor tweaks aren't either. edit: Also, the differences between chimp and human are pretty consistent with plain increase in the volume (and number of neurons), if you control for, hmm, cultural differences. You can teach chimps sign language; chimps can use and invent tools. We do it better, of course - larger brains are more powerful, perhaps the longer childhood also helps, etc.

That could work, though i'm very wary of the software analogies. The software in general makes extremely poor analogy to software in form of learning algorithms like the neural networks.

The way I see it, there are certain cognitive modules - a small number of them, well identified - and instincts, emotions, reflexes. Parameters of those can be adjusted by evolution. The evolution can also adjust network properties, perhaps even with some specificity. At same time, evolution is not substantially better at creating specialized modules than at other morphology, and the pleistocene evolution to our psyche is comparable in extent to pleistocene evolution to our bodies - we could up or down regulate the anger, but we did not evolve new emotions, or new hard wired things to be angry about, or new hard-wired cognitive fallacies.

And we definitely shouldn't evoke evolution as explanation for everything, as per "Given the enormous number of adaptive problems our Pleistocene ancestors faced, Tooby and Cosmides estimate that the human mind consists of "hundreds or thousands" of such evolved modules (1995, p. 1189). Thus inspired, Evolutionary Psychologists postulate evolved modules for incest avoidance, sexual attraction, mate choice, jealousy, mate retention, allocation of parental resources, kin relations, alliance formation, aggressive threat, danger avoidance, food preferences, habitat choice, and so on for all manner of complex cognitive and behavioral functions (Tooby & Cosmides 1992, p. 110)."

(quoting from this review: http://host.uniroma3.it/progetti/kant/field/ep.htm )

Can you be more specific in your disagreement. Most of what I got from the original post was the suggestion to be very suspicious of humans-evolved-complicated-brain-modules type arguments. I understand if that suspicion isn't the local consensus, but what's wrong with it?

I guess. I did not want to focus attack on specific ideas from evolutionary psychology though. But yes I need to add more citations on how DNA affects the connections between neurons.

If this were the case, I really would have expected prominent evolutionary biologists to have noted it

This is one of those issues in science where the controversies are ideological in origin, so one should not put too much trust in the prevailing opinions in the academic establishment (especially publicly expressed ones).

Basically, the problem is that application of evolutionary theory to human behavior (i.e. human sociobiology) quickly leads into territory that is, from today's predominant ideological perspective, too frightful to contemplate. Some 30-40 years ago, there was a raging controversy over whether human sociobiology is a legitimate field of inquiry. Its proponents argued that it's just a regular application of evolutionary theory, while its opponents maintained that it's epistemologically flawed and at the same time motivated by evil and dangerous ideology. The former, of course, claimed in return that the latter were themselves motivated by fear of their own ideology being falsified.

As the outcome of this controversy, around two decades ago a compromise was struck. The field would be recognized as a legitimate academic discipline, but under a tacit agreement to remain limited to questions with relatively low ideological impact, and insofar as ideological spin is put on the results, it would be in a respectable direction. (The opening essay in The Adapted Mind has a pretty explicit statement of these founding principles.) Moreover, the field would be rebranded as "evolutionary psychology," abandoning the "sociobiology" moniker, which had, as a result of the prior controversies, acquired sinister connotations.

This new field has been successful in building a good public image, and some of its practitioners have become prominent and respectable public intellectuals. On the other hand, as may be expected, the more hard-line anti-sociobiology ideologues have continued to be its harsh critics, and to this day, discussion about its fundamental epistemological validity has remained an ideological battleground.

http://en.wikipedia.org/wiki/Criticism_of_evolutionary_psychology#Testability

In another thread, you linked to some book, I forgot the name, there was critique from another prominent guy saying it's not how mind works. Clearly there is critique.

Do you have an explanation why do you expect considerably more complex changes to wiring in the brain, than to gross morphology, i.e. shape of organism? I honestly just don't see why it would be more common for evolution to hardwire a reflex than to make a new organ. edit: Okay, for the organs there is the argument that the existing organs are pretty damn good. Still, there's plenty of opportunity for improving e.g. human locomotion, and pressure, too, and one can clearly see how slow did the bones change shapes.

edit: ahh, now i have a great question: Why would it be so much more common to evolve some complex but hard to separate from culture psychology, than it was to evolve verifiable, simple, straightforward hardwired reflexes? There's not a single well defined, agreed upon reflex i can think of that humans have, which chimps lack. There's a lot of evo-psych stuff that is allegedly unique to us humans, evolved during our hunter gatherer times.

I think this really should nail it down WRT plausibility of evo-psych. It propositions big number of very complex psychological adaptations, over the time when no straightforward, agreed upon hard wired reflexes evolved. Not just gross morphology. Anything well identifiable at which we can look and say - okay, chimps don't have this innate reflex - and agree.

A randomly wired network still can have different number of short range vs long range connections, vertical vs horizontal connections etc.

Brain is not randomly wired; it consists of cortical columns - a basic unit replicated over the brain - and some of the wiring is very specific. The axons can very accurately find their destinations. Different areas of brain can be built with different parameters of the network organisation. There are good reasons not to adopt tabula rasa - blank slate - that's why i propose the slates prepared for specific work, in minor ways. We certainly can evolve different fur on different parts of our bodies - and so we can evolve different network properties in different areas of brain. But if you want to link specific sets of neurons in specific ways from the DNA to build a circuit that performs an evolved function - all chances are you can not do that, as there isn't any genes which express just in those neurons.

The lined slate example is to make it clear that I am not arguing in favour of complete 'tabula rasa'.

With regards to our brains being learning machines, the neuroplasticity is good evidence that parts of brain can learn the tasks not originally intended, at the levels of performance close to the normal, suggesting only minor innate specialization.