the evolving mind

Does an increase in testosterone levels cause behavior x? Or does behavior x cause an increase in testosterone? Or, even more confoundingly, is the answer both?

The relationship between behavior and brain chemicals is a complex one. Why? Our biology will certainly influence our behavior. But behavior can influence our biology as well. For example, perform this experiment: crack a big smile right now. Did you feel anything? I bet you did. The behavior of smiling caused changes in your brain chemistry. And it likely felt good. The reverse is true. Alter your brain chemistry in a similar fashion and you are more likely to smile.

In a recent study researchers found a link between the hormone progesterone and “interpersonal closeness.” In their experiment, female subjects in pairs proof-read a botany manuscript together or played a cooperative computer game. The results -

The progesterone levels of women who had engaged in the emotionally neutral tasks tended to decline, while the progesterone levels of women who engaged in the task designed to elicit closeness either remained the same or increased.

So there we have behavior influencing a hormone level. In a follow-up phase, the researchers discovered a link likely pointing in the other direction.

“During the first phase of the study, we found no evidence of a relationship between progesterone and willingness to sacrifice,” Brown said. “But a week later, increased progesterone predicted an increased willingness to say you would risk your life to help your partner.”

A pushmi-pullyu, by the way, is a fictional creature from an old Dr. Dolittle book/movie. The creature had two front ends connected by a middle. And that may be an apt metaphor for the relationship between brain chemicals and behavior. It seems to be a bi-directional beast.

Technorati Links: behavior, hormones, neurology

We’ve got another sunny day in my neighborhood. At this moment there is a juvenile cardinal deep in the cypress tree outside my window. It is waiting for its instincts to tell it to go ahead a risk a flight to the feeder.

Yesterday we had sunshine. And then it poured. Really poured. But now it’s bright sunshine. Having lived in a sunnier but extremely arid state–New Mexico–as well as a somewhat less wet but place more prone to days of overcast–Vermont–I really love Florida. We enjoy many days of sunshine, for at least some of the day. And abundant rainfall. I do enjoy a good rainfall. As for lightning storms: how could you not be fascinated by those?!

I wonder what the cardinal “thinks” about thunder and lightning.

Technorati Links: birds, florida, nature

To the leaders go the first fruits, the first cut of meat.

Bring the best of the firstfruits of your soil to the house of the LORD your God. (Exodus 23-19)

In chimpanzee society, the first and the best is not voluntarily offered to dominant individuals. Instead, coveted foods are taken by force or threat of force.

The first offspring of every womb belongs to me, including all the firstborn males of your livestock, whether from herd or flock. Redeem the firstborn donkey with a lamb, but if you do not redeem it, break its neck. Redeem all your firstborn sons. No one is to appear before me empty-handed. (Exodus 34:19-21)

Why “first” fruit and best portions? Purity and importance. Sure, give generic canned goods to the poor. But in your gift basket to the boss, make it top-shelf cheese and expensive wine.

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Technorati Links: belief, bible, status

If my recollection serves me, at a Smithsonian Museum exhibit on fashion years ago I learned that the blue-is-for-boys and pink-is-for-girls custom is less than a century old. Previous to that, it was actually the reverse! What is acquired by culture can seem so natural, but may not be at all.

Certainly, I can reason my way into understanding how pink could be associated with boys. Pink is a diffuse red and red is hotter than blue. Boys tend to be less placid than girls–bingo, a connection.

Pure speculation aside, I recently encountered an article about how facial coloring provides gender cues. It seems that for our kind, the “subtle shading or luminance” around the eyes and mouths of others is key to identifying gender.

So, is a pink coloration more male-like or female-like? Guess.

“Studies have shown that an androgynous face is considered male if the skin complexion is redder, and considered female if the complexion is greener,” says Dupuis-Roy. “However, it is the opposite for the mouth. A woman’s mouth is usually redder. Our brain interprets this characteristic as female.”

Damn. Another complicated answer. While one facial cue to maleness is an overall redder skin complexion, a redder mouth area is likewise a cue to femaleness. Interesting.

As for why it is considered unmanly for me to wear my pink-and-blue striped button-up shirt to the local sports bar–even by me–that likely is all about culture.

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[source: http://www.sciencedaily.com/releases/2009/05/090527121049.htm]

Technorati Links: gender, sexuality

No, you won’t ever guess what this is. Man-made, certainly. Woven fibers at x200. Very small fibers.

Sometimes science is accused of “un-weaving the rainbow,” of making things less awesome by exposing how they work. I don’t see it. Not the rainbow part, but the un-weaving making things less. To me, scientific understanding adds additional dimensions to rainbows and all phenomena.

What’s more, science spawns the technological advances that provide the potential for new awe-inspiring experiences. Look through a telescope, for one.

What is the above? A medicinal patch used to treat back aches. When a person doesn’t hurt, it is a lot easier to perceive rainbows.

Thanks for the weaving and the un-weaving, science!

Technorati Links: meaning, microscope

A Florida State University team, “led by noted biosocial criminologist Kevin M. Beaver at FSU’s College of Criminology and Criminal Justice,” has found a link between a gene variant and both gang membership and violent behavior [source]. In Beaver’s own words -

“Previous research has linked low-activity MAOA variants to a wide range of antisocial, even violent, behavior, but our study confirms that these variants can predict gang membership,” he said. “Moreover, we found that variants of this gene could distinguish gang members who were markedly more likely to behave violently and use weapons from members who were less likely to do either.”

MAO (monoamine oxidases) is a class of enzymes the play a role in the break-down of important neurotransmitters, including serotonin, norepinephrine and epinephrine. That the researchers discovered not only a genetic link, but one to a gene understood to play a central role in behavior, is significant. I adds real weight to the finding. Stronger science leads to a better understanding by revealing the underlying mechanisms to phenomena. That is why it is reductionistic in nature.

Of course, a link is just that, a link. It wasn’t called a cause for good reason. I don’t think it is unreasonable to speculate that a gene variant may . . . predispose(?) a person to engage in types of behavior, but that many other variables, genetic and environmental, also play important roles.

Technorati Links: behavior, genetics

The above photo makes me wish I could shrink myself down to a size suitable for spelunking in the private parts of blossoms. That would be so cool!

Of course, I would get no sexual pleasure out of it. The pleasure would be of a different sort. (I don’t think one could even say that either the pollinating insect probing into a flower, nor the plant itself, experience any sexual pleasure from the activity.) I wonder: would I need to wear a gas-mask to deal with the intensity of fragrance? Would my hands stick to the pollen stuck to the flower?

And what if a bee flew in after me?

Okay, that imaginary adventure suddenly grew a bit hair-raising.

Technorati Links: flowers

Can you find truth in a cartoon? Sure. But is the truth you find truly true? As an atheist, I think to agree with the message below. But I certainly have my biases. So I try to find objective data to inform me. And from what I have seen, the contrary position is definitely NOT true: that atheists are somehow more dangerous than believers.

[comic thanks to atheistcartoons.com]

Technorati Links: atheism, religion

Rather than skeletons in their closets, creationists have fossils beneath their feet. As you may have read elsewhere, a new hominid species has recently been unearthed. Perhaps more exciting than the specific find, to me, was the discussion of the area in Spain where it came from. (Yes, Spain: not an area that has come to mind when I have contemplated ancient hominids.) It’s fossil-rich. As are countless other yet-discovered areas, no doubt.

What it means is that evolutionary science will continue to march along while those who cling to obsolete mythologies will be left scratching their heads, attempting to justify their stance.

Technorati Links: belief, culture

Is this sample edible? What is it? Hint: the pic is at x200. And you might want to refine the first question. Answer and additional pic below the fold.

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Technorati Links: microscope, puzzle