Behold – our recent ancestor, the gorilla, and ourselves, the human:

There are many characteristics that separate us from our monkey fathers. Most notably, factors that mark the evolution are the use of fire, use of tools, and a bigger brain. A recent study suggests that it is actually the onset of the use of fire that explains the ability to begin to grow a larger brain. According to a timeline of human history, the earliest Homo Sapiens appeared shortly after beginning to use fire to cook food:

What is it about cooking that allowed us to grow bigger brains? As the brain grows bigger, more energy is required to sustain the increased number of neurons. Gorillas could spend up to ten hours a day obtaining the food necessary to sustain both their brain and large body mass. Why is it that humans can spend significantly less than 10 hours per day to consume our required energy intake, but gorillas must be constantly eating? The tradeoff is in how we prepare our food. Gorillas live off of a raw food diet, whereas humans cook food. Cooking can be thought of as “pre-digesting.” Because we’ve already broken down much of the food by cooking, the calorie absorption process becomes more efficient than if the food had been raw, and requires that we put in a significant amount of energy to just digest. On just a raw-food diet of the gorilla, evolution could not have been possible, because the gorilla could never consume enough energy via raw food in a day to support a larger brain. The use of fire to prepare food paved the way for the evolution of organisms that could support significantly larger brains.

I’m no expert on nutrition, but as a general public service announcement after seeing this study, I would caution going on a raw food diet for a long period of time. Sure, as a vegetarian my canine teeth aren’t being put to use like they’re supposed to be. But I can still consume enough energy to be healthy by cooking my veggies. For those of you who want to try a raw food diet… well, I’m seeing some pretty solid evidence that the whole reason we’re here is because of cooking. And you can’t really argue with evolution.

For more information on the topic, see the transcript of a recent Live Chat hosted by Science.

Sources:

Raw Food Not Enough to Feed Big Brains – Science

Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution – PNAS

Food for Thought – Science

They can’t stop talking about her. “Look at how popular and successful she is!” “Look at how stupid and ditsy she is!” “What has she done to be so famous?” … Well, I don’t care if she’s smart or stupid, rich or poor. The only things I see when she’s on the screen are those voluptuous curves. Regardless of what you think of her, Kim Kardashian has what most men dream of. Since this is a nerds’ blog, we’re going to take the moment to examine why we men like those curves so much.

Men like women with large curves because these provide an adaptive advantage, increasing the likelihood of the propagation of genes. Wide hips are adaptive because they make child birthing easier (more successful); large breasts may provide more nutrition during nursing. The men who go for the curves are more likely to make successful offspring; those offspring incidentally share the same instinct for curves and eventually make more progeny; and the cycle continues.

Now, Kim Kardashian is what you call a supernormal stimulus. She has everything that normally elicits a positive response but exaggerated. “Supernormal stimulus,” by the way, is attributed to the famous ethologist Niko Timbergen, who found that substituting a mamma-seagull’s white beak with its one red spot for a stick with three red spots made the chicks way more excited for food. Many more such examples have been described in a variety of animals.

But anyway, I am a male and my primitive brain can’t help but to love Kim Kardashian. One could say the male brain is predisposed or hard-wired to love curves like Kim’s. Actually, some folks are still amazed to hear that there are neural correlates of this or that (you see this in the news all the time – “scientists now found the brain mechanisms behind gambling,” social anxiety, or enhanced hearing in the blind. The list goes on). There won’t be any behavior, feeling, thought, etc without neural correlates. I dare you to show otherwise.

In an article on love and the brain, Psychology Today columnist Marnia Robinson describes the neural mechanisms that make prairie voles (similar to mice) pair bond, or stay as a couple for at least one round of mating). It has to do with the distribution of oxytocin receptors, which makes the vole associate its mate with the dopamine reward pathways, meaning that a couple stays together (“in love”) long enough to raise some pups. Marnia notes that we, like the voles, are “programmed to pair bond—just as we’re programmed to add notches to our belts.” In another post in her column, she drives the point home:

“Pair bonding is not simply a learned behavior. If there weren’t neural correlates behind this behavior, there would not be so much falling in love and pairing up across so many cultures. The pair-bonding urge is built-in and waiting to be activated… The vital point is that our pair bonding penchant arises from physiological events, not mere social conditioning… So, even though many Westerners appear to be caught up in a chaotic hook-up culture for the moment, it doesn’t mean that we humans are, by nature, as promiscuous as bonobo chimps or that pair-bonding inclinations are superficial cultural constructs.”

What Marnia means is that committed relationships (perhaps marriage, too) are natural, and therefore you don’t have to worry that everyone you know is only interested in hooking up because they should prefer committed relationships; eventually they’ll all settle down and all will be right in the world. I hope you will forgive me for interpreting Marnia’s writing as a promotion of marriage and an attack on hook-up culture (after all, the title of her post is “Committed Relationship: Like It Or Not, You’re Wired For It”). Humans have a genetically-based neural system that enables them to fall in love and pair bond (again, it shouldn’t be surprising that we have a neural system for this; the only question is what roles do genes and environment play on it). But just because it is there doesn’t mean it is 100% deterministic.

It’s true, in some species the best strategy for gene propagation is for the couple to share the responsibility of child rearing. Evolution favors individuals with the monogamy instinct and it just so happens that monogamous relationships feel good to them. What Marnia is driving at is that you don’t have a choice but to end up in a committed relationship because your brain is “wired for it”.

Is that really true? Decision-making can be described as synaptic integration of relevant inputs based on their weights or importance. Unless you are a cocaine addict running on empty, the factors going into most decision have fairly weighted synaptic representation (i.e. a crack-head’s brain won’t allow factors other than crack to have a big vote in the decision-making congress). Just because a brain is predisposed toward some trait or behavior doesn’t mean that that trait is 100% deterministic. This idea of relative cognitive liberty here doesn’t even invoke free will; the decisions you make are based on the brain’s wiring, your previous experiences, probability, etc – not some soul that does what it wants.

And why does it matter that monogamy is the “natural” thing to do? Who cares what we are by nature? Last I checked, by nature dudes can be expected to throw themselves at every cake, cookie, jar of peanut butter and sexy lady they see. Haven’t witnessed that recently at the local Shaw’s… And it wouldn’t matter if “society” were “making” us do that – we control society! We choose what’s acceptable. If I want to sleep around instead of getting married, that’s my choice! (isn’t it ironic how it’s the conservative right that always worries about threats to personal freedoms and tries to deny personal freedoms in the name of traditional values?).

That doesn’t mean we can ignore our nature; we do have innate mechanisms that pull or push us in different directions – I don’t love Kim Kardashian because I chose to, but because as a man I have certain preferences built in. But here’s the catch: just because I think Kim is attractive doesn’t mean I’m going to ditch my girlfriend and hop on the next plane to Hollywood. I can control myself and stay in a meaningful relationship; I can inhibit this reptilian instinct. Likewise, not every man prefers Kim to someone with a flatter topology. We do have innate preferences, but they all have different impact on what we do or how we feel. Next time you see a headline about the genetic basis or experience-driven neuroplasticity of some trait or other, be wary: not everything is as intensely deterministic as the neuropundits will have you believe. For now stay content that you can enjoy Kim Kardashian’s curves without committing any social faux pas.

Nigel Barber. The evolutionary psychology of physical attractiveness: Sexual selection and human morphology. Ethology and Sociobiology. Volume 16, Issue 5, 1995, 395-424

Decision Making in Recurrent Neuronal Circuits
Xiao-Jing Wang. Neuron. 60, (2) 215-234.

Committed Relationship: Like It Or Not, You’re Wired For It

Human Brains Are Built to Fall in Love

Instead, I’d like to draw attention to a particular aspect of Isaac Asimov’s writing, of which I can’t help being reminded after reading these reports.  As the father of the term “robotics” and all things relating to it, Asimov dealt with nearly all of the issues relating to artificial intelligence.  A few of his fictional robot characters even developed human-like, self-aware consciousness and creativity.  But the one thing which stands out about these characters was that their consciousness was rarely a design of their creators, but rather a fluke.  Minute variations in the mechanized construction of their positronic brains amounted to  unique, creative minds.

Asimov’s choice to author conscious robots as results of random chance forces us to think about how human consciousness evolved in reality.  It may be that such a consciousness is not strictly required for an organism to dramatically enhance its chances of survival and reproduction. We seem to assume that our superior cognitive abilities grant us an enormous advantage over other species, that the sort of consciousness which makes us self-aware, reflective and creative was the “end result” in a very long line of brain development.  But evolution does not work towards such a specific end.  There are plenty of other species (e.g. viruses) that persist with just as much vigor as us, despite their lack of cognitive powers associated with the forebrain.  Perhaps only a minor, random mutation resulted in a dramatic and permanent change in the brain, a change which ultimately amounted to consciousness.  Who knows what the odds are that such an intelligence evolved, or will evolve again in a computer simulation?  At least we can be reassured that, on a long enough time scale, even the most unlikely event can occur.

In any case, Boston University’s own Isaac Asimov has made many a prediction with his science fiction, and many more can be expected.

“Artificial life forms evolve basic intelligence”-Catherine Brahic

I would hate to marginalize the Creationists that may frequent this blog, but, it is becoming difficult to ignore all of the

Ready for a chat, perhaps?

evidence for Evolution piling up higher and higher.  This conglomerate of information is contributed to by almost all fields of study- from Archeology to Biology, and in a recent surge in the rapidly growing field, Neuroscience.  Unfortunately for us, submitting to the idea of Evolution forces us to think of ourselves and our fellow humans as a little less awesome or unique- we have always reveled in our species immense capacity for complex language processing, as well as other things of course.  But it didn’t just pop up out of nowhere a couple million years in.

To expand upon the research being done by neuroscience in exploring the evolution of the brain, this article focuses on Wernicke’s area (known for its dedication to processing auditory language information) in chimpanzees.  This study used design-based stereologic methods to estimate regional volumes, total neuron number and neuron density.  When compared to what we know about the human brain, the results are intriguing.

What did they find?  A leftward asymmetry of this language area in the monkey brains.  What does this mean to us?  It suggests that the left lateralization of the language area in the brain (left = language, left = language, first thing to memorize in Psych 101) originated before our cutting-edge human species, prior to the appearance of our modern human language.

This investigation may seem generally boring- these Chimpanzees aren’t Darwin’s finches or anything- but it certainly is significant in showing Neurosciences’ huge potential for contribution to the case of Evolution.  They showed that a language specialization that is key to our unique language capabilities actually evolved prior to the emergence of modern humans, serving as a pre-adaptation to modern human language and speech.  Studies like these are closing the gap between ancestral species, and unfortunately, making us all feel a little less special about our leap to civilized society.  Way to go Evolution.

Original Article:    http://rspb.royalsocietypublishing.org/content/277/1691/2165.full?sid=912995c2-144b-45bb-b92c-d7c0196d1fef#ref-5

Similar articles investigating monkey brains and language adaptions:  http://current.com/1ri8u4c

Ps.- If anyone studying at BU is really really into Evolution, I highly recommend the Ecuador Study Abroad Program… A trip to the Galapagos Islands (on a private yacht, no less) and to the Charles Darwin Research Station is a chance of a lifetime.