A theory of male and female Sociopathy, pt 2

Note: this is just a theory, developed in reaction to recent conversations. 

As we were discussing Friday, one form of female sociopathy (at least relevant to this conversation) likely involves manipulating or coercing others into providing resources for her children.

There are a couple of obvious tropes:

  1. The evil stepmother, who shunts resources away from a man’s first child, toward his later children. 
  2. The cuckoldress, who tricks or convinces a man to care for another man’s children (this is not always seen as evil, since the male drive to provide for children is triggered at least partly by their proximity, since men cannot give birth, and thus men feel genuine affection for children who happen to be around them,)
  3. The crazy ex, who sues a man for all he is worth, doing her best to prevent him from being able to provide for any future children. 

How crazy are women? 

NSDUH_AMI-_2012_GRAPH_148270_2

22%–slightly more than 1 in 5–women have been diagnosed with a mental illness, at least according to all of the data I’ve seen. Since mental illness peaks during the childbearing ages and falls off quickly after menopause, we can also assume that this rate is closer to 1 in 4 during these years. 

(The dramatic problems our Native American communities are facing is a separate matter, deserving of its own post.)

The odd thing about this data is that mental illness rates are higher for women than men, despite the fact that mental retardation and mental disability rates are higher for men than women. Men are more likely than women to have serious conditions like non-verbal autism and schizophrenia, more likely to be homeless or commit suicide. When things go terribly wrong, the sufferers are disproportionately male (an unfortunate side effect of the Y chromosome causing greater male variability than female variability on a variety of traits.) 

So why on earth do more women than men suffer from mental illness? 

Perhaps some forms of mental illness confer some unexpected benefits on women. 

Many (perhaps most) “mental illnesses” correlate with a single personality trait–neuroticism

“Previously we thought that mental illnesses such as depression, schizophrenia, bipolar disorder, and substance abuse, were completely separate diseases,” Ystrøm says.

But research has now shown that these illnesses are often linked. If you suffer from one mental illness, you are more likely to develop another. And if someone in your immediate family has a psychiatric illness, your risk increases not only for this disorder, but for all other disorders.

These findings have led researchers to suspect that there could be a common underlying factor that increases an idividual’s risk of mental illness, overall. … 

Ystrøm and colleagues have used new statistical methods to look for patterns in personality, mental disorders, genes, and environmental factors, among the twins in the Twin Register. 

And the answer to the question the researchers asked is: yes, neuroticism seems to be the personality trait that best describes the risk of all mental disorders. …

“This one trait doesn’t explain everything. Anyone can develop a mental illness…”

And in women, neuroticism correlates with… more surviving offspring (in at least one study)

Taking an evolutionary approach, we use data from a contemporary polygynous high-fertility human population living in rural Senegal to investigate whether personality dimensions are associated with key life-history traits in humans, i.e., quantity and quality of offspring. We show that personality dimensions predict reproductive success differently in men and women in such societies and, in women, are associated with a trade-off between offspring quantity and quality. In women, neuroticism positively predicts the number of children, both between and within polygynous families. Furthermore, within the low social class, offspring quality (i.e., child nutritional status) decreases with a woman’s neuroticism, indicating a reproductive trade-off between offspring quantity and quality. 

What is neuroticism, in the Big 5 Personality Traits* sense? 

*Note: I am not endorsing or denying all five traits one way or another.

It’s worrying. Mothers who worry more about their offspring have more offspring–though it’s quite easy to imagine that the causality points in the opposite direction as the study’s authors conclude–poor women with lots of skinny babies have more reason to worry about their children than women with a few fat babies. 

When are women most likely to experience mental illness?

Immediately after the birth of a child. It’s called post-partum depression, and it can be very bad–one woman in my moms’ group ended up in the mental hospital after developing post-partum psychosis. Andrea Yates famously drowned her five children during a bout of post-partum depression/psychosis.

Why on earth would women develop a debilitating mental illness at the most vulnerable time in their offspring’s life? Wouldn’t natural selection select rather quickly against anything that makes women worse at taking care of their offspring? 

Let’s turn to everyone’s favorite genetic disease, sickle cell anemia. SCA is famous for being a relatively simple genetic mutation of the sort where if you have one copy of the sickle cell gene, you are less likely to get malaria, and if you have two copies, you tend to die. In areas where malaria is common, the cost of having a quarter of your children die from SCA is lower than the cost of loosing them to malaria. 

Personality traits, including neuroticism, generally exist on a continuum. People may become more neurotic when life warrants it, and less neurotic when they don’t need to worry. A mother with a new baby is in a very vulnerable state–she has just lost a good deal of blood, may not be able to walk, and has an infant to care for every other hour, day and night. It is not a normal state by any measure. It is a time when being extra attentive and extra aware of threats and predators is in a woman’s interest.

It is also a time when women are most in need of help from their mates, relatives, or other friends. Increased neuroticism may also prompt others to attend more closely to the new mother, helping her out. . Increased neuroticism may be so helpful during this time period that a few women getting way too much neuroticism and becoming extremely depressed or even killing their children is a cost outweighed by the increased survival of babies whose mothers had moderate levels of neuroticism. 

Let us note that nature doesn’t care about your feelings. Male praying mantises who allow themselves be eaten by their mates have more offspring than the ones who don’t, but that doesn’t mean male praying mantises enjoy getting eaten. Children who die of sickle

cell anemia don’t much appreciate that their siblings were protected from malaria, either.

An increase in neuroticism immediately after the birth of a baby may prompt a mother to take better care of it, but that doesn’t mean she enjoys the neuroticism. Neither does it mean that post-partum depression is healthy, any more than sickle cell anemia is healthy just because it’s a side effect of a trait that helps people avoid malaria. 

But wait, I have more studies!

Reproductive Fitness and Genetic Risk of Psychiatric Disorders in the General Population

The persistence of common, heritable psychiatric disorders that reduce reproductive fitness is an evolutionary paradox. Here, we investigate the selection pressures on sequence variants that predispose to schizophrenia, autism, bipolar disorder, major depression and attention deficit hyperactivity disorder (ADHD) using genomic data from 150,656 Icelanders, excluding those diagnosed with these psychiatric diseases. … Higher polygenic risk of autism is associated with fewer children and older age at first child whereas higher polygenic risk of ADHD is associated with having more children. We find no evidence for a selective advantage of a high polygenic risk of schizophrenia or bipolar disorder. Rare copy-number variants conferring moderate to high risk of psychiatric illness are associated with having fewer children and are under stronger negative selection pressure than common sequence variants. …

In summary, our results show that common sequence variants conferring risk of autism and ADHD are currently under weak selection in the general population of Iceland. However, rare CNVs that also impact cognition are under stronger selection pressure, consistent with mutation-selection balance. The hypothesis that a selective advantage accounts for the prevalence of sequence variants conferring risk of schizophrenia and bipolar disorder is unproven, but rather this empirical evidence suggests that common sequence variants largely escape selection as their individual effect sizes are weak.

Unfortunately, this study mostly looks at the data in aggregate, instead of breaking it down by males and females. (And I don’t know why they would bother excluding people who actually have the conditions they are trying to study, but perhaps it doesn’t make much difference.) 

Thankfully, they did break down the data by male/female in the tables–Table 1 and Table 2. These tables are confusing, but the takeaway is that mental illness has a bigger effect on male fertility than female fertility. 

Also: Fecundity of Patients with Schizophrenia, Autism, Bipolar Disorder, Depression, Anorexia Nervosa, or Substance Abuse vs. their Unffected Siblings

Results Except for women with depression, affected patients had significantly fewer children (FR range for those with psychiatric disorder, 0.23-0.93; P < 10−10). This reduction was consistently greater among men than women, suggesting that male fitness was particularly sensitive. Although sisters of patients with schizophrenia and bipolar disorder had increased fecundity (FR range, 1.02-1.03; P < .01), this was too small on its own to counterbalance the reduced fitness of affected patients. Brothers of patients with schizophrenia and autism showed reduced fecundity (FR range, 0.94-0.97; P < .001). Siblings of patients with depression and substance abuse had significantly increased fecundity (FR range, 1.01-1.05; P < 10−10). In the case of depression, this more than compensated for the lower fecundity of affected individuals.

Conclusions Our results suggest that strong selection exists against schizophrenia, autism, and anorexia nervosa and that these variants may be maintained by new mutations or an as-yet unknown mechanism. Bipolar disorder did not seem to be under strong negative selection. Vulnerability to depression, and perhaps substance abuse, may be preserved by balancing selection, suggesting the involvement of common genetic variants in ways that depend on other genes and on environment.

Now, this study gets interesting in its graphs: 

m_yoa120017f1
From Fecundity of Patients with Schizophrenia, Autism, Bipolar Disorder, Depression, Anorexia Nervosa, or Substance Abuse vs their Unaffected Siblings

In every case, mental illness has a bigger effect on male fertility than female–and in the case of depression, it has no effect on female fertility. 

But wait: 

m_yoa120017f2
Same source.

This graph is confusingly labeled, but it is breaking down the correlation on the brothers and sisters of people with mental disorders. So the first dot represents the brothers of people with schizophrenia; the second dot represents the sisters of people with schizophrenia. 

None of these effects are huge, and some of them changed when “comorbidities were included in the analysis,” though it’s not clear exactly what that means–the word comorbidity in this context refers to people with more than one diagnosis. 

For the objectives of this study, we first analyzed each disorder separately without accounting for comorbidities. A secondary analysis was then performed that corrected for comorbidities by analyzing all disorders simultaneously.

So when you analyze all of the disorders together, sisters of schizophrenics had no increased fertility, and neither did the siblings of people with bipolar. Depressed men had average fertility, while depressed women actually had slightly above average fertility. The results for anorexia, substance abuse, and autism didn’t change. 

And from Spain: Seven Dimensions of Personality Pathology are Under Sexual Selection in Modern Spain

Personality variation is increasingly thought to have an adaptive function. This is less clear for personality disorders (PDs)—extreme variants of personality that cause harm in most aspects of life. However, the possibility that PDs may be maintained in the population because of their advantages for fitness has been not convincingly tested. In a sample of 959 outpatients, we examined whether, and how, sexual selection acts on the seven main dimensions of personality pathology, taking into account mating success, reproductive success, and the mediating role of status. We find that, to varying extents, all personality dimensions are under sexual selection. Far from being predominantly purifying, selective forces push traits in diverging, often pathological, directions. These pressures differ moderately between the sexes. Sexual selection largely acts in males through the acquisition of wealth, and through the duration (rather than the number) of mates. This gives a reproductive advantage to males high in persistence–compulsivity. Conversely, because of the decoupling between the number of mates and offspring, the promiscuous strategy of psychopaths is not so successful. Negative emotionality, the most clinically detrimental trait, is slightly deleterious in males but is positively selected in females, which can help to preserve variation. 

It’s interesting that the invention of birth control may have inadvertently selected against promiscuous psychopaths–rather similar to the theory that abortion is responsible for the decrease in crime since the early 90s. 

“Negative emotionality” is likely equivalent to “neuroticism.”

There are two obvious reasons why mental illness might have more of an effect on males than females–one is that mental illness might simply be mores severe for males than females, on average. The second is that mental illness interferes more with holding down a job than with being a housewife, so women with mental illnesses have more options than men. 

Less obvious, though, is that some of these traits might actually be beneficial–in small quantities–for women.

That’s enough for now; let’s continue this discussion on Friday. (Wednesday is book club.) 

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A theory of male and female Sociopathy pt 1

Note: this is just a theory, developed in reaction to recent conversations. 

Let us assume, first of all, that men and women have different optimal reproductive strategies, based on their different anatomy. In case you have not experienced birth yourself, it’s a difference of calories, time, and potential death. 

In the ancestral environment (before child support laws, abortion, birth control, or infant formula):

For men, the absolute minimal paternal investment in a child–immediate abandonment–involves a few minutes of effort and spoonful of semen. There are few dangers involved, except for the possibility of other males competing for the same female. A hypothetical man could, with very little strain or extra physical effort, father thousands of children–gay men regularly go through the physical motions of doing just that, and hardly seem exhausted by the effort.

For women, the absolute minimal parental investment is nine months of gestation followed by childbirth. This is calorically expensive, interferes with the mother’s ability to take care of her other children, and could kill her. A woman who tried to maximize her pregnancies from menarchy to menopause might produce 25 children. 

If a man abandons his children, there is a decent chance they will still survive, because they can be nursed by their mother; if a woman abandons her child, it is likely to die, because its father cannot lactate and so cannot feed it. 

In sum, for men, random procreative acts (ie, sex) are extremely low-cost and still have the potential to produce offspring. For women, random procreative acts are extremely costly. So men have an incentive to spread their sperm around and women have an incentive to be picky about when and with whom they reproduce.  

This is well known to, well, everyone. 

Now, obviously most men do not abandon their children (nor do most women.) It isn’t in their interest to do so. A man’s children are more likely to survive and do well in life if he invests in them. (In a few societies where paternity is really uncertain, men invest resources in their sisters’ children, who are at least related to them, rather than opting out altogether.) As far as I know, some amount of male input into their children or their sisters’ children is a human universal–the only variation is in how much. 

Men want to invest in their children because this helps their children succeed, but a few un-tended bastards here and there are not a major problem. Some of them might even survive. 

By contrast, women really don’t want to get saddled with bastards. 

We may define sociopathy, informally, as attempting to achieve evolutionary ends by means that harm others in society, eg, stealing. In this case, rape and child abandonment are sociopathic ways of increasing men’s reproductive success at the expense of other people. (Note that sociopathy doesn’t have a formal definition and I am using it here as a tool, not a real diagnosis. If someone has a better term, I’m happy to use it.)

This is, again, quite obvious–everyone knows that men are much more likely than women to be imprisoned for violent acts, rape included. Men are also more likely than women to try to skip out on their child support payments. 

Note that this “sociopathy” is not necessarily a mental illness, (a true illness ought to make a dent on one’s evolutionary success.) Genghis Khan raped a lot of women, and it turned out great for his genes. It is simply a reproductive strategy that harms other people. 

So what does female sociopathy look like? 

It can’t look like male sociopathy, because child abandonment decreases a woman’s fertility. For a woman, violence and abandonment would be signs of true mental defects. Rather, we want to look at ways women improve their chances of reproductive success at the expense of others. 

In other words, female sociopathy involves manipulating or coercing others into providing resources for her children. 

But it’s getting late; let’s continue with part 2 on Monday. (Wednesday is book club.)

Antagonistic Selection and Invading Armies

We don't naturally look like this
We don’t naturally look like this

Evolution is a fabulous principle, but it can only do so much. It has yet to give us titanium bones or x-ray vision, nor has it solved the problem of death. It even gives us creatures like praying mantises, who eat their mates.

Genetically speaking, men and women are actually quite similar, at least compared to, say, trees. There’s a great deal of overlap between male and female instincts–we both get hungry, we both fall in love, we both think the Ghostbusters remake was an abomination.

While evolution would like* to code for perfect men and perfect women, since we are the same species and ever male has a mom and every female has a dad, genetics ultimately can’t code for perfect men and perfect women. *yes I am anthropomorphizing

Remember, there are only two chromosomes which code for sexual development, the so called XX (female) and XY (male). Both men and women have at least one X, but no women have a Y.

It doesn’t work out that men are, like, expressing half female genes and half male genes, since the Y chromosome blocks the expression of some of the female genes. However, men still have those genes.

Sexual antagonism or “sexual conflict” occurs when a genetic trait that makes one sex better at reproducing makes the opposite sex worse at reproducing:

Interlocus sexual conflict is the interaction of a set of antagonistic alleles at one or more loci in males and females.[6] An example is conflict over mating rates. Males frequently have a higher optimal mating rate than females because in most animal species, they invest fewer resources in offspring than their female counterparts. Therefore, males have numerous adaptations to induce females to mate with them. Another well-documented example of inter-locus sexual conflict is the seminal fluid of Drosophila melanogaster, which up-regulates females’ egg-laying rate and reduces her desire to re-mate with another male (serving the male’s interests), but also shortens the female’s lifespan reducing her fitness.

From, A recent bottleneck of Y chromosome diversity coincides with a global change in culture
From: A recent bottleneck of Y chromosome diversity coincides with a global change in culture

In humans, for example, women benefit from being thin and short, while men benefit from being tall and bulky. But a short, thin woman is more likely to have a short, thin, son, which is not beneficial, and a tall, bulky man is likely to have a tall, bulky daughter–also not beneficial.

Whatever instincts we see in one gender, we likely see–in some form–in at least some members of the opposite gender. So If there is–as some folks around these parts allege–an instinct which makes women submissive to invading armies, then it likely affects some men, too.

For the few men who do survive an invasion, not protesting as your wife is gang raped might keep you alive to later reproduce, too

Hence the recent rise of cuckoldry fetishes.