Brain and Behavior
gregladen | August 4, 2010It is well established among those who carry out, analyze, and report pre-employment performance testing that slope-based bias in those tests is rare. Why is this important? Look at the following three graphs from a recent study by Aguinis, Culpepper and Pierce (2010):
Figure 1. Illustration of the typical finding of no slope-based differences and intercept-based differences favoring the minority group (Panel A), and the possibility that there are slope-based differences (Panels B and C) together with no intercept-based differences (Panel B) and small intercept-based differences (Panel C…
gregladen | July 10, 2010One of those really cool and useful "evolution stories" gets verified and illuminated by actual research. And blogging!
An oystercatcher is a wading bird of the family Haematopodidae, distributed in one genus, Haematopus. As is the case with many coast loving birds, there has been confusion about the limits of the 11 or so species known to exist worldwide. That itself is an interesting story (Hocke 1996), but one we will not go into now.
Adult coastal oystercatchers (some species are not coastal) eat all sorts of animals found in the intertidal zone, including shellfish of all sorts,…
gregladen | December 29, 2009This is Chart 1 from Race, Evolutoin and Behavior by J. Philippe Rushton, originally published in the Unabridged Edition of same.
gregladen | December 28, 2009Many people assume human brains vary genetically and genetic variation maps to races. But the races are not real and genetic variation can't explain brain differences. Because, dear reader, brains don't work that way.
Let's look just at the brain part of this problem.
There are between 50 and 100 billion neurons in the human brain, and every one is connected to a minimum of one other neuron to produce about 100 trillion connections. So when we are thinking about how the brain is wired up, we have to explain how so many connections can be specified to make the brain work.
There are…
gregladen | December 22, 2009This post started out as a comment that would have gone here (but would have done just as well here). But it became sufficiently long and possibly interesting that I figured it would make a good, if somewhat rough, blog post.
The presumption being examined here is that humans are divisible into different groups (races would be one term for those groups) that are genetically distinct from one another in a way that causes those groups to have group level differences in average intelligence, as measured by IQ. More exactly, this post is about the sequence of arguments that are usually made when…
gregladen | December 2, 2009As pointed out moments ago by DrugMonkey, the brain of HM is at this very moment being cross sectioned at The Brain Observatory.
Here
gregladen | September 20, 2009If you watch a fake hand standing in for your right hand, and it is touched with a brush while at the same time your left hand, hidden from view, is similarly touched, you feel your right hand being touched. This spooky finding is called "phantom touch" and was reported in a recent issue of PLoS ONE.
...we report a perceptual illusion where people experience "phantom touches" on a right rubber hand when they see it brushed simultaneously with brushes applied to their left hand. Such illusory duplication and transfer of touch from the left to the right hand was only elicited when a homologous…
gregladen | September 2, 2009Today's falsehood is the idea that individual animals act for the benefit of their own species.
Let me give you an example. When I was a kid, I watched a nature show about cougars. The show 'documented' a single female cougar going about doing cougar-things and being generally cougar-like. At one point she had cute little baby cougar kittens.
Then a flood came. The stream near her chosen lair swelled its banks and threatened to drown the kittens. So, she carried one of the kittens up the hill to a new lair. She went back to get the second kitten, and the flood waters were even higher…
gregladen | June 7, 2009Note: First Woman Michele Obama confirms my suspicion
Who is smarter, men or women?
Any college teacher (at least in the social sciences and life sciences) who has ever paid attention to their own stats know that women do better than men in college classes.
OK, women are smarter. But why?
There are all kinds of post hoc explanations given for this like "Girls get better grades because professors are men, nod nod wink wink" and so on. What a load of crap. Women are smarter than men on average, among the smartest people there is no emperical evidence that women are underrepresented, and…
gregladen | May 12, 2009According to a study just coming out in the Journal of Sexual Medicine, "variations in emotional intelligence--the ability to identify and manage emotions of one's self and others--are associated with orgasmic frequency during intercourse and masturbation."
In short, the study found:
Emotional intelligence was not associated with ... age and years of education, nor did we find a significant association between emotional intelligence and potential risk factors for [female orgasmic disorder] FOD such as age, body mass index, physical or sexual abuse, or menopause. We found emotional…
gregladen | May 9, 2009Evil Genes: Why Rome Fell, Hitler Rose, Enron Failed, and My Sister Stole My Mother's BoyfriendWhen I first received this book to review, I thought "Oh, great, another one of these pop evolutionary psychology books by some academic with a large mortgage payment" (or words to that effect). But then I read it and my attitude got better.
The theme of this book is as the title says, evil ... at several scales, and understanding evil from a neuro-psychological perspective. Here, the genes themselves are actually relatively unimportant except as part of the necessary steps to build a human…
gregladen | May 3, 2009Lithium has long been used as a psychotherapeutic drug, and treatment with lithium demonstrably reduces incidence of suicide. Lithium also occurs naturally in groundwater to varying degrees. This study explores the relative amount of Lithium in groundwater and suicide in 18 municipalities in Oita prefecture, Japan over a period running from 2002 to 2006. There are two principle findings:
1) There is a negative correlation between standardized (adjusted) suicide rates and the amount of lithium in the water; and
2) It does not take much lithium to produce this effect.
The study reports…
gregladen | March 6, 2009I'm starting to worry that the last few Friday Weird Science write-ups by Scicurious (who seems, these days, to be the primary blogger at Neurotopia) have been of papers that I happen to have read. Just so you know: Thousands of papers are published per week across the diverse sciences, and although Scicurious tends to deal with life science and I tend to read life science, the chances of this particular harmonic convergence across bloggers regarding papers published over the last decade is statistically almost zero. More likely, Scicurious and I just have similar taste ... or lack thereof…
gregladen | February 27, 2009 This barking dog is not very smart. But it could make a good Republican. The only thing harder to understand than Michele Bachmann is the Republican Party. Bachmann is hard to understand in this way: How can a person with her mind be an elected member of congress?!?!??? The Republican party is hard to understand in this way: How can a party that is trying to become more rather than less relevant keep putting Michele Bachmann on the podium in places like the National Party Convention and, most recently, at CEPAC??!?!?!?
I can't explain any of this, but I can at least redescribe the…
gregladen | February 25, 2009The male and female human brains are different. Some of the better documented differences are similar to differences seen in other mammals. They are hard to find, very small, and may or may not be of great significance. Obviously, some are very important because they probably relate to such things as the ability ... or lack thereof ... to bear offspring. But this is hardly ever considered in the parodies we see of these differences.
[Repost from Gregladen.com]
You have all seen the sometimes funny, sometimes not cartoon depictions of these differences, for example this one:
Obviously,…
gregladen | February 12, 2009Or not.
Much is made of the early use of stone tools by human ancestors. Darwin saw the freeing of the hands ad co-evolving with the use of the hands to make and use tools which co-evolved with the big brain. And that would make the initial appearance of stone tools in the archaeological record a great and momentous thing. However, things did not work out that way.
It turns out that up-rightedness (bipedalism), which would free the hands, evolved in our ancestors a very long time (millions of years) prior to our first record of stone tools. The earliest upright hominids that are…
gregladen | February 10, 2009But according to this scientific diagnostic tool, I have the brain of a 25 year old. How old is your brain?????
You'll have to know how to read Japanese to make this work, or you can just follow these instructions:
1) Click on start. The diagnostic tool will count down from 3 and show you some numbers.
2) Remember where the numbers are. The diagnostic tool will make the numbers go away and replace them with empty circles.
3) Now click each circle in turn, in order from smallest to largest. Zero is smallest (that's what screwed me up ... for some reason my brain would not remember that…
gregladen | January 26, 2009I thought we already knew this, but here goes:
Schizophrenia may blur the boundary between internal and external realities by over-activating a brain system that is involved in self-reflection, and thus causing an exaggerated focus on self, a new MIT and Harvard brain imaging study has found.
The traditional view of schizophrenia is that the disturbed thoughts, perceptions and emotions that characterize the disease are caused by disconnections among the brain regions that control these different functions.
But this study, appearing Jan. 19 in the advance online issue of the Proceedings of the…
gregladen | December 31, 2008Naturalism is a potential source of guidance for our behavior, morals, ethics, and other more mundane decisions such as how to build an airplane and what to eat for breakfast.1 When it comes to airplanes, you'd better be a servant to the rules of nature or the airplane will go splat. When it comes to breakfast, it has been shown that knowing about our evolutionary history can be a more efficacious guide to good nutrition than the research employed by the FDA, but you can live without this approach. Naturalism works when it comes to behavior too, but there are consequences. You probably…