Quote reblogged from Neven Mrgan's tumbl with 18 notes
A spot on your arm is sending signals to your brain. There is an upset area of your epidermis wanting attention. You reach for it without thinking, and you scratch, nails digging into skin repeatedly. Why? It feels better, sometimes; sometimes it doesn’t. It’s addictive, somehow. Why?
Neven Mrgan’s tumbl: Scratching
Neven would make an excellent evolutionary biologist/psychologist.
His argument (scratching is a non-adaptive extension of an adaptive “touch is good” urge) raises the important points in a thoughtful way (i.e. identifying the difference between “it feels good,” a proximate explanation, and the more satisfying ultimate explanation “why does it feel good?”).
My hunch is that the scratching urge is adaptive on the whole. Neven underestimates the benefit to removing bugs/thorns/etc, possibly because these nuisances are much less in our clothed world. But to our evolutionary ancestors, ticks, leeches, and who knows what other kinds of pests and parasites would have been a much bigger problem. Chimps, our closest relatives, spend significant time grooming each other and removing these kinds of critters. Similarly, splinters, rocks, and thorns could become a significant problem (and a big infection risk) if not removed.
I agree with Neven that the human urge to remove scabs/itch bug bites is likely a nonadaptive extension of an adaptive trait… but I estimate the positive payoff for removing parasites/splinters to be much bigger than that for scratching off a scab + irritating a bug bite.
Source: mrgan
Link reblogged from Give Me Something To Read with 9 notes
If you’ve ever had a good, long look at the human phallus, whether yours or someone else’s, you’ve probably scratched your head over such a peculiarly shaped device. Let’s face it—it’s not the most intuitively shaped appendage in all of evolution. But according to evolutionary psychologist Gordon Gallup of the State University of New York at Albany, the human penis is actually an impressive “tool” in the truest sense of the word, one manufactured by nature over hundreds of thousands of years of human evolution.
(thanks, Nostrich)
Ahh, the semen displacement hypothesis (that the “coronal ridge” on the end of the penis was evolved to remove semen from previous partners during intercourse).
When we talked about this paper in my Paternity, Fidelity, and Parenting class last semester, I think I dropped the best line of my discussion section career. We had just read about the study (described in this article as well), where college students males were found to “thrust deeper and faster, in the wake of allegations of female cheating.”
I argued that this wasn’t really a new discovery, rather it was a commonly held notion. To back up my claim, I quoted R. Kelly’s “Trapped in the Closet Part 4.” Kelly is suspecting his wife of cheating (“And a man picked up the phone…”), but has sex with her as soon as he gets home. But not just any sex, “And that’s when I started going crazy / Like I was trying to give her a baby.” I’m not sure my professor enjoyed the reference.
Source: givemesomethingtoread
Link reblogged from Give Me Something To Read with 3 notes
The evolutionary role of cookery.
Richard Wrangham is the man. He also proposes that cooking is one of the reasons for the sexual division of labor we see in almost every modern + hunger-gatherer society.
Source: givemesomethingtoread
and i find myself agreeing that yes, this is indeed brilliant in how well the theory below passes the smell test. except in one area, that is…sports. part of “culture.” and i am pretty sure, at least in my case, that being a fan of the knicks/yankees has absolutely nothing to do with mating. at all. in any abstract or concrete sense. i could go into more—and maybe i will, one day—but for now, let’s just say that maybe that’s another reason why the idea of sports is fundamentally fantastic.
“Mostly because everyone is constructing an identity at all times, whether or not they even realize it. Mostly because you can sweat almost anything down to this basic biological truth: Culture is a mating ritual. We are looking for ways to differentiate ourselves so as to attract one another. That is the deep dark secret of everything we do. It might be that black and white.” Nick SylvesterMore from that freaking brilliant critique of Hipster Runoff
Sports have everything to do with mating! Athletes are competing for status and prizes, and demonstrating their physical fitness to potential mates. Sport is sexual selection just like mating dances and epic elephant seal battles.
Why do we love watching sports? I think we’re pretty hard-wired to find sexual competitions fascinating. While being able to recite the 2002 Buckeye starting lineup isn’t going to get me laid, it’s not hard to see how intimate knowledge of mating rituals could have a big genetic payoff - by learning Kobe’s moves or Bellicheck’s plays.
Source: stephanieho
