The Swedish government, a world leader in gender equity, decided last year to ban bars and restaurants from enforcing different ages of admittance for men and women. Up until then it was commonplace to allow women to enter at, say, age 20, while the men had to wait until they were 22 or so to get in.

Now, I know this will shock you all, but according to local police this exercise in equality has led to increased levels of violence in Stockholm. According to “Stockholm City”:

We noticed that violence went up last autumn, that’s why we launched an inquiry. It shows that when bars have dropped age limits for guys, they admit these younger guys who can’t handle alcohol very well, and then you have a fight on your hands, says Lars Lehman.

Why, it’s almost as if men and women were different or something!

In Unequal by nature: A geneticist’s perspective on human differences, James F. Crow states:

Two populations may have a large overlap and differ only slightly in their means. Still, the most outstanding individuals will tend to come from the population with the higher mean.

This is a trivial observation. It is biologically relevant because heritable quantitative traits are to a great extent the raw material for evolution, and, they generally follow an approximate normal distribution. The reasoning is simple, many loci of small independent additive effects are a good approximation of the genetic architecture of many phenotypes, and this structure simulates, roughly, the independent random variables which result in a normal distribution because of the central limit theorem. Obviously two of the most important parameters in the normal distribution are the mean (which is also the mode & median in a perfectly ideal distribution) and variance around that mean.
Unfortunately, human minds are not unbiased statistical inference devices. Otherwise, cognitive psychologists would be shorted many interesting questions. It seems that the implications of the normal distribution and its most famous parameters (the mean and the variance) should be obvious to all college educated individuals. But my experience is that this isn’t true, unfortunately. Experience indicates that principles are often more profitably imparted visually, so I took 10 minutes and cranked out a pretty picture via Excel that you can view below the fold.

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I can’t get enough Dinosaur Comics. This might be my favorite site on the internet.

T-Rex on: HeLa Cells, Thermodynamics, Genetics, Philosophy, Intelligent Design, and Science vs. Religion (prequel, 1, 2, and 3).

OK, enough. Get back to work!

The March 2006 issue of Cytogenetic and Genome Research was entirely dedicated to genomic imprinting. I know some of y’all cats are into this business. There’s one by Haig entitled Intragenomic Politics, and several on regulatory mechanisms which are more my speed, including one about small non-coding RNAs.

Of course, the articles aren’t free, but perhaps arrangements could be made for the really important ones.

In the long winded post below I referred to genetic conflicts in pregnancy. If you are curious about this, I highly recommend Mother Nature by Sarah Hrdy. Though the topic is placed in the context of female evolution (of our species) in general, it gets a thorough treatment. If you are interested in the technical literature, I recommend this review, Genetic Conflicts in Pregnancy by David Haig. Since it is a review, it is less analytical and formal than much of Haig’s work, so it reads easily. You can get the pdf on Haig’s website.

The paper that was supposed to be out nearly a week ago is finally on the PNAS site. This isn’t the first time this has cropped up. Additionally, I can’t believe that someone is writing all the press releases which give early dates for release on the website, rather, I’m assuming that the IT guys at PNAS are lazy. Anyway, I don’t want to be a bitch, but this is a pattern so I figure I should note it publically (hey, when you waste 15-20 minutes combing the website for a paper multiple times, resentment builds up).

Every once in a while I realize something with my conscious mind that I’ve understood implicitly for a long time. Such a thing happened to me yesterday, while reading a post on Stalin, by Amritas. It is this:

S = P + E

Social Status equals Political Capital plus Economic Capital

Now, if someone were to have just shown me that equation, I would probably have been unimpressed. It seems like a definition, a tautology, a pseudo-mathematical formulation of the expression “socioeconomic status”. What I suddenly realized, though, is that this formula has tremendous explanatory power. So much so, that I want to call it the “Universal Law of Interpersonal Dynamics”. Now, I am not a psychologist, sociologist, or anthropologist, and I am not familiar with the literature, so I don’t claim that it’s an original idea. I’m sure that such a thing must have be expounded upon by someone before me. But I’m a fairly well-educated person, and I’ve never encountered such a thing in any popular forum. Assuming that it more-or-less stands after it is posted, it deserves to be popularized.

Here’s an example of its explanatory power: If we assume that a major human drive is to maximize S, we can predict that people with high P will attempt to minimize the value of E (since S-maximization is a zero-sum game). And so we see. Throughout history there has been an attempt to ennoble P while stigmatizing E. Conversely, throughout history, people with high E use it to acquire P. Thus, in today’s society we see that socially adept people, who have inborn P skills, tend to favor socialism or big government – where their skills are most valuable, while economically productive people are often frustrated by the fact that their concrete contribution to society is deplored.

Now, you might ask yourself why the reverse isn’t true, why people with high P don’t use it to acquire E, while people with high E don’t attempt to stigmatize P? Well, I think that is true. But, while the equation is mathematically symmetrical, the nature of P-talent and E-talent is not. P-talent can be used to acquire E from the E-adept, but the E-adept are no match for the P-adept in the attempt to stigmatize P. Furthermore, P is endogenous to the system, while E is exogenous. In other words, the P-adept have the ability to manipulate the system itself to make P-talent more valuable in acquiring E, while the E-adept have no ability to manipulate the external environment to make E-talent more valuable in acquiring P.

Of course not all people fall neatly into one of these two categories. Some people are naturally both P-adept and E-adept, while others, unfortunately, are neither. This, too, is asymmetrical in its implications, since the both-adept have a choice of pursuing either P-strategies or E-strategies (indeed, there are many real-world applications which leverage both), but the neither-adept have no choice but to support a P-strategy, since cooperation of this kind is itself a P-strategy (libertarianism, by contrast, would get them neither P nor E).

Put another way: Socialism is all about taking the “economic” out of “socioeconomic status”, meaning that gaining social status becomes a purely political game. Which is why it appeals to both the socially adept and the economically inadept. They both hate status that is based on dirty economics. Those boors don’t deserve it.

Now, I don’t think that this is a new phenomenon at all. Back in hunter-gatherer times, I have no doubt that there were already people who gained social status through P-strategies. But the social systems were so small, and the harsh economic realities to obvious, that it probably took a lot of political-talent units to equal one economic-talent unit. Now, however, societies are very large and complex, and the sources of economic productivity are not well-understood. The playing-field has tipped dramatically toward the socially adept, the merely economically adept now often, endearingly, termed “losers”.

I leave it as an exercise to the reader to show how the Universal Law of Interpersonal Dynamics predicts the following:

1. All institutions will tend to be dominated by the P-adept
2. All institutions that have no in-built exogenous criteria for measuring its members’ status will inevitably be dominated by the P-adept
3. Universities will inevitably be dominated by the P-adept
4. Within a university, humanities and social sciences will be more dominated by the P-adept than natural sciences
5. Within a university, humanities and social sciences will politically dominate the natural sciences
6. People who work in universities and the government will tend toward socialism
7. Libertarians will tend to be found among the socially inadept
8. Unmarried women will tend toward socialism
9. Hard-working, upwardly mobile people will tend away from socialism (even when their absolute status is low)

(Cross-posted on Rishon Rishon.)

Janet points me to this post which points to this research which reinforces the theory that placental environment might have a strong effect on the phenotype of the fetus. Since I’ve expressed an interest in genomic imprinting let me respond to Jill at Feministing‘s query, “why do we have to know?”, she doesn’t have to, but some of us certainly follow this research closely. The reason isn’t because we are obsessed with the biology of homosexuality, as that is the phenotype in question, but rather it elucidates questions and dynamics in evolutionary biology that we find interesting.

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While I’m recommending weblogs, I thought I’d point readers to Clark Gobles’ Mormon Philosophy & Theology. Now, I know that most readers here aren’t religious, and there is probably a mildly anti-philosophical bias as well, but, if you want to sample an “Intermontane” flavor of Derrida discourse, Clark is your man. Think of him as the Napoleon Dynamite of philosophy and cognitive psychology.

If you’re at all interested in long-term potentiation (LTP) and long-term depression (LTD), you’re going to want to read this review/opinion by Govindarajan, Kelleher, and Tonegawa in July’s Nature Reviews Neuroscience. This team has previously written one of the best comprehensive reviews of neuronal translation control mechanisms. They do a brief reprise on that business, broadly suggesting which signaling molecules are involved and emphasizing that protein synthesis happens local to the stimulated synapses. Then they turn their attention to synaptic tagging/capture experiments for the bulk of the paper.

As some here must be sick of hearing by now, memories are likely to be stored as changes in synaptic weights. LTP and LTD are increases and decreases respectively in synaptic weight. The long-lasting (late) phases of LTP and LTD require protein synthesis. Govindarajan et al make the case that this is achieved by increased efficiency in general translation machinery. Synaptic tagging and cross-tagging experiments have shown that the proteins generated by a given L-LTP or L-LTD inducing stimulus can be captured by synapses that have only received E(early)-LTP or E-LTD inducing stimuli, thus producing late phase plasticity.

Govindarajan et al note that transport speeds are known for important plasticity-related proteins, like AMPA receptor subunits, and that it would take them about an hour to move the length of your average dendritic branch. In tagging experiments, if L-LTP and E-LTP stimuli are separated by around this length of time, the capture of plasticity proteins does not occur. So they are suggesting that plasticity proteins are probably only shared within a dendritic branch, producing ‘clusters’ of synapses that have undergone long-term change. I’m not sure the transport speed issue is central to their theory or if you could simply argue that the generated proteins are degraded in that hour, but one prediction they didn’t make that I think follows is that in cell populations with shorter dendritic branches you should see greater spread of these induced proteins or maybe a longer time window for capture, and vice versa.

The clustered plasticity model carries advantages over a dispersed model where synapses are changed at more random sites across the neuron in part because stimulated synapses in the same dendritic branch sum supralinearly. The whole of the stimulation is greater than the sum of its parts. To get cells to fire in the dispersed model would take a lot more network activation than that in the clustered model. The authors argue that this has implications for ease of memory recall.

I have an interest in trying to understand the relationship between broad-scale network activities like theta oscillations and sharp-wave ripples and the small scale on which plasticity is studied. There is a little bit about that in this review.

…assuming that connectivity between the set of presynaptic neurons and postsynaptic neurons is random, clustered plasticity would be advantageous compared with dispersed plasticity only if the density of active inputs is high enough to enable the setting of potentiation and depression tags at multiple synapses within at least one dendritic branch in the postsynaptic neuron. In support of this, 30-50% of hippocampal cells are active in a given environment, hippocampal activity resembles theta-burst stimulation, which has been used as a robust inducer of plasticity, and 45-75% of synapses are capable of undergoing plasticity. Therefore, in an episode (a sequence of related events; the hippocampus is important for acquiring memory of such sequences), it is probable that there is sufficient activation so as to result in many dendritic branches in the hippocampus containing multiple tagged synapses. The probability of this being the case is even higher when sharp waves are considered. In rats, it has recently been shown that sharp wave activity during exploration carries information about the environment explored by the animal. Furthermore, sharp wave-type activity would lead to high enough activity to enable activation of multiple synapses in a dendritic branch.

I don’t think this quite does it, but at least folks are starting to turn their attention to it. It’s weird to try to make actual predictions about memory based on this hour timeframe of integration. Would a given dendritic branch represent events in about a two-hour window with a peak in the very middle? When a salient or unexpected event occurs that might drive neuromodulation and increase protein synthesis occurs, do events an hour on either side of that event benefit from the upregulation? How much time worth of events is integrated in a single sharp-wave ripple or compressed in a single theta oscillation? All I know now is about distances that are integrated and it seems like it is not an hour’s of exploration.