Month: June 2006

The technologies of mass agriculture, including genetic engineering, prevented the mass starvation of humanity in the last century.  But today most of humanity lives on just 12 plant species and some scientists are worried that a lack of variety may prove our undoing.  Some types of banana, for example, have already been wiped out or are threatened (Snopes is more cautious but verifies the basic facts). 

To protect our seed patrimony is the goal of the Svalbard International
Seed Vault.

The high-security vault, almost half the length of a football field, will
be carved into a mountain on a remote island above the Arctic Circle. If the
looming fences, motion detectors and steel air-lock doors are not disincentive
enough for anyone hoping to breach the facility’s concrete interior, the polar
bears roaming outside should help….

Its precious contents? Seeds  —  millions and millions of them  —  from
virtually every variety of food on the planet.

Thanks to Carl Close for the pointer.

In species where females are promiscuous, there is a big conflict of
interest between males and females over the amount of resources each
child should get. The father of one child probably won’t be the father
of the next (or even of others in the same litter), so his genes —
which he passes on to the child — should evolve to try to get more
resources for his offspring. Genes that come from the mother,
meanwhile, evolve to suppress this effect, so that all her offspring
aren’t fighting each other for resources. In species where females are
monogamous, in contrast, male and female interests are more or less the
same, since the same male is likely to sire many litters with the same
female.

In humans, mice and other mammals of our sort, the
activities of the placenta are — ready for this? — largely controlled
by the father’s genes. Now consider what happens when certain close
species try to mate. Female deer mice are much more promiscuous than
female oldfield mice, so a male deer mouse’s genes are predicted to
fight for resources much more than a male oldfield mouse’s genes would.
Consistent with this, when a male deer mouse mates with a female
oldfield mouse, both placenta and fetus become huge, and the mother
often dies. Any fetus that manages to be born is one third bigger than
babies from either species usually are. When the oldfield mouse is the
father, on the other hand, the pregnancy is much less risky for the
mother — but the baby is a runt.

…female chimpanzees are much, much more promiscuous than human females.
So, assuming you could get fertilization, here’s my prediction: if the
chimpanzee were the father, the pregnancy would be extremely dangerous
for the mother. Probably, few pregnancies could be carried to term. Any
children that did result would be huge. In contrast, if the human were
the father, the children would be small, and both mother and child
would be more likely to survive.

Tyler, Alex, Alex’s wife Monique, Bryan (Caplan), Ilia (Rainer) and I had a fun conversation on Thursday.

A standard story says that women like cads for short term relationships, to get good sex (i.e., genes), and dads for long term relationships, to get security and comfort (i.e., resources to raise kids).  Of course some men are good in both roles, but most men are thought to be better at one role than the other.

Woman always want both sex and security, but they seem to prefer "bad  boy" cads more when they are young, and dads more when they are older.  Why?  We were looking less for proximate psychological causes and more for functional explanations.  We came up with these four theories:

1.  Young women must practice having relationships, in part to discover the distribution of guys out there and their own ability to attract guys.  This requires short term relationships.  But it is not clear why these should be more with cads rather than dad candidates.  And this would predict young women avoid sex when practicing, to avoid having kids.  This theory applies to better to young teens than to young women.

2.  Instead of having all her kids with a dad, many women may have enough negotiating power to get a dad to support her even if she has one kid with a cad.   Dads object less to supporting a cad kid created before they met, as a cad kid created during their relationship suggests that it won’t be the last.  A cad kid early in life can be written off to the "foolishness of youth," and she can credibly claim that she didn’t intend for this to be a cad kid; she had hoped the cad would be a dad.

3.  Girls more than women expect parents to help with their mistakes.  A young woman expects a cad kid to be cared for not by a dad but by her parents and extended family.  Since parents die eventually, older women are less likely to have such support available.  This theory predicts that women without living parents would be less attracted to cads, all else equal.

4.  Young people have stronger incentives to signal than older people, since they are still forming long term attachments, and want to attract the best partners.  Young women compete to attract cads in order to signal their attractiveness and social power, and having sex with cads helps to attract cads.   Women compete more for cads than for dads because cad quality is easier to see in young men – it can take many years to reveal who are the best resource providers.  This theory predicts young women have less interest in private unobserved relationships with cads.

The truth is probably a mixture of these theories.   But some are probably more important that others.

TC: Here are related posts on the topic.

"Up until now, people thought that [shyness] was mostly related to
avoidance of social situations," says co-author and child psychiatrist
Monique Ernst. "Here we showed that shy children have increased
activity in the reward system of the brain as well."

Why this
would be the case is still not clear. "One interpretation is that
extremely shy children have an increased sensitivity to many types of
stimuli–both frightening and rewarding," says Guyer. There are other
possibilities as well, says Mauricio Delgado, a psychologist at Rutgers
University in Newark, New Jersey. For example, increased activity in
the striatum may help shy children cope with the anxiety of stressful
situations, although not enough so to help them overcome their shyness.

…Because shy children
appear to be more sensitive to winning and losing, they may experience
emotions more strongly than others, putting them at risk for emotional
disorders such as anxiety and depression. On the flip side, shy
children may experience positive emotions such as success very
strongly, helping them succeed…

OK, that is from scans of only 32 people, 13 of them shy.  But that is actually more than usual for such a study.  Here is the link.  Here is Jonathan Rauch’s famous piece on being an introvert, well worth reading. 

Chris Masse sends me further neuro links, here and here.  Here is a recent neuro study on how women react to erotic images.