Category: Science

Selection bias

Who shows up for experiments?

Peer nominations of pathological personality traits were collected on
1442 freshmen participating in a study regarding personality and 283
students who initially provided consent to participate but failed to
show up for the assessment.  Ten peer-based personality disorder scales
and eight IIP-64 scales were entered into two separate multiple
logistic regression procedures to predict the probability of
nonparticipation.  There was a significantly higher probability of
participation if peers nominated someone as having more histrionic,
obsessive–compulsive, self-sacrificing, and intrusive/needy
characteristics.  Students were significantly less likely to participate
if peers nominated them as being higher on narcissism or
non-assertiveness.  Results suggest it may be more difficult to obtain
sufficient numbers of people high in narcissistic traits than
individuals with other personality traits.  Researchers may need to
employ novel strategies to recruit individuals with narcissistic traits
for experimental studies.

By the way, I’ve never showed up for any experiments.  I would think the procedure also discriminates against the anti-social, a trait which may be to some extent correlated with narcissism.

The link is from BPS Digest, which also informs us that people born in late winter are smarter; I can only imagine how smart tall, left-handed people, born in late winter [alas, I am not tall], must be…

What makes individuals take up science?

In a nutshell, mentors:

The most common response to the question ‘What inspired you to take up science?’ – given by respondents including Dr Colin Berry, Peter Cochrane, Jorge Mayer, Simon Singh and Christopher Llewellyn Smith – is that they were inspired by teachers or mentors. Typical of such reponses are Alom Shaha‘s description of ‘gifted teachers, whose enthusiasm for their subjects was relentless and infectious’, and Michael Wilson‘s account of ‘inspirational and rigorous teachers in high school, who engendered an insatiable intellectual hunger for factual knowledge, and who encouraged observation and deductive thinking’.

Survey respondents often point to one or two particular individuals who made a lasting impact. Josef Penninger, for instance, was inspired by ‘a great mentor and teacher’, and argues that ‘most of us became what we became because of one dominating person, who moved us into a certain direction’. Frances Downey, James Enstrom, Pat Norris, John Zarnecki and Anton Zeilinger describe inspirational mathematics and physics teachers, Thomas Addiscott and Eliot Forster discuss inspirational chemistry teachers, and Kenneth Freeman had ‘a very capable and very overworked teacher’ who taught him mathematics, physics and chemistry. Meanwhile, Professor Sir Colin Berry, Keith Davies and William Ledger found inspiration in their biology teachers.

Here is much more, via www.politicaltheory.info.  Here is the answer of Sophie Petit-Zeman: falling in love with the teacher.

The most suprising two paragraphs so far today

“How tall your parents are compared to the average height explains
80 to 90 percent of how tall you are compared to the average person,”
Dr. Vaupel said. But “only 3 percent of how long you live compared to
the average person can be explained by how long your parents lived.”

“You
really learn very little about your own life span from your parents’
life spans,” Dr. Vaupel said. “That’s what the evidence shows. Even
twins, identical twins, die at different times.” On average, he said,
more than 10 years apart.

Here is the full story, which is interesting throughout.  But of course the day is young, and I haven’t seen Bryan, Robin [Hanson], and Alex yet…

Why People Die By Suicide

The studies on those who attempt suicide multiple times and on the vigorous association between past and future suicidality (even accounting for "kitchen sink" variables) are consistent with the view that people habituate to self-injury and thereby gain the ability to enact increasing severe suicidal behaviors.

That is the main argument of Thomas Joiner’s Why People Die by Suicide.  Here is the book’s home page.  Here is an excerpt.  Here is a summary.  By the way, athletes, who are used to harming themselves, commit suicides at relatively high rates.

The traditional economic approach compares the costs and benefits of staying alive, with option value thrown in for good measure.  It seems more realistic to treat people as having periodic suicidal urges, but (fortunately) usually lacking the capability to execute those urges.  Why some people find reason to work their way "up the ladder" of capabilities is the next question.  Perhaps the mechanisms behind suicide have more to do with employment, and with economic growth, than we used to think.  Rather than making an analysis of suicide more like modern economics, should economics become more like the theory of suicide? 

More people die by suicide in New York City than are murdered; here are twenty facts about death.  Have I mentioned?  It seems to be "Death Day" over at MarginalRevolution this lovely Tuesday…

Claims you all can laugh at

Some of the Irish claim to have invented a perpetual motion machine

As a young child I read this was impossible, but frankly I’ve long been convinced of the contrary.  The universe itself seemed like a counterexample.  It goes and goes and goes and goes.  Lots of stuff happens.  Stars explode, galaxies crash, planets get downgraded, etc.  Where does a vacuum get its energy from anyway?  And isn’t the "cosmological constant" a big free push?

Now perhaps our universe is not truly "perpetual."  Or perhaps it involves "no net expenditure of energy."  I’ve heard it called "a free lunch," through some kind of quantum effect and subsequent inflation. 

But still, the universe, as a perpetual motion machine, seems to me like a good enough version of what people have been looking for.  (Imagine your venture capital pitch: "Well, it’s not as Big or as Important as The Universe, but it does operate according to the same physical laws…")  The universe was produced by some process, and perhaps a smaller and more local version of the idea is possible.  Or does it come only in one size?  Well…I’d better stop before I make any more scientific blunders…

I can’t get over the idea there is a free lunch floating around out there.  Perhaps I read too much Julian Simon in my formative years.

Addendum: Here are the seven warning signs of bogus science.

The Female Brain

New mothers lose an average of seven hundred hours of sleep in the first year postpartum.

…In one study, mother rats were given the opportunity to press a bar and get a squirt of cocaine or press a bar and get a rat pup to suck their nipples…Those oxytocin squirts in the brain outscored a snort of cocaine every time.

Both are from the new and noteworthy The Female Brain, by Louann Brizendine.  Here is a very brief (and somewhat skewed in the direction of politically correct) summary.  Here is more.  Here is a Deborah Tannen review.

There are way way way too many books on gender differences.  Most of them just string together the usual well-known templates, but I read every page of this one with interest.  The best parts focus on the role of hormones.

Not everyone will appreciate the punchy style — "There’s a new reality brewing in Sylvia’s brain, and it’s a take-no-prisoners view" — but everyone who wants to marry or have kids should read this book.

Status competition, rural Indian style

In rural Hindu villages in India…widows are expected
to be perpetual mourners, austere in their habits, appetites and dress;
even so, they often jockey for position, said Richard A. Shweder, an
anthropologist in the department of comparative human development at
the University of Chicago.

“Many
compete for who is most pure,” Dr. Shweder said.  “They say, ‘I don’t
eat fish, I don’t eat eggs, I don’t even walk into someone’s house who
has eaten meat.’  It’s a natural kind of social comparison.”

The article focuses on the psychology of fame-seeking.

The progress of science

In one experiment, experts in karate, boxing, kung fu, and tae kwon do all took turns striking the dummy in the face.

The researchers were surprised to find that boxing is the fighting style capable of delivering the most force in a single punch.

Boxer Steve Petramale delivered about 1,000 pounds (453.6 kilograms) of impact force, the equivalent of swinging a sledgehammer into someone’s face…

The tae kwon do spinning back kick delivered more than 1,500 pounds (680.4 kilograms) of force, while the kung fu flying double kick produced about 1,000 pounds (453.6 kilograms) of force.

But the undisputed winner practices a discipline known for its ability to deliver a knockout: Muay Thai, also known as Thai boxing. 

Melchor Menor, a former two-time Muay Thai world champion, uses a simple technique to incapacitate his opponents: a knee to the chest at close quarters [TC: I guess that doesn’t count as a "punch"  Oh well.].

Menor himself was surprised at how powerful this move can be.

"I wasn’t expecting to have the highest force. When he said the power of the knee [kick] was equal to the power of a 35-mile-an-hour [56.3-kilometer-an-hour] car crash, it was humbling."

It also turns out that a kung fu punch is as fast as a snake.  Who would have known?  Here is the full story, which perhaps explains why I prefer tennis.

The ten weirdest cosmologies?

Here is the list, courtesy of GeekPress.  But they are not trying very hard.  Here is one candidate:

3. Superfluid space-time

One of the most outlandish new theories of cosmology is that space-time is actually a superfluid substance, flowing with zero friction. Then if the universe is rotating, superfluid spacetime would be scattered with vortices, according to physicists Pawel Mazur of the University of South Carolina and George Chapline at Lawrence Livermore lab in California – and those vortices might have seeded structures such as galaxies. Mazur suggests that our universe might have been born in a collapsing star, where the combination of stellar matter and superfluid space could spawn dark energy, the repulsive force that is accelerating the universe.

Duh!  That’s not weird at all.  My favorite weird cosmology is missing from the list: time is an illusion, all possible universes exist, and that includes many universes with false memories and traces of a supposedly distant past.

Then there is always "elephants all the way down…"

New research on what triggers autism

1. Here is the story.

2. Your English is better than you think.  But on incorrect uses of "hopefully" I will not cede ground.

3. Some books do better in paperback.

4. A Delta list of best barbecue restaurants, based on reader input, via Bob Lawson.  The Virginia selections are weak plus they left off Lockhart, Texas altogether.  It is a better list for the South proper.

5. Jane Galt on deficits, and also on "unfair competition," do go send her some compliments in return…

6. Gorbachev on Bush and Putin.

Harry was Correct

Harry: You realize of course that we could never be friends.
Sally: Why not?
Harry: What I’m saying is – and this is not a come-on in any
way, shape or form – is that men and women can’t be friends because the sex
part always gets in the way.
Sally: That’s not true. I have a number of men friends and
there is no sex involved.
Harry: No you don’t.
Sally: Yes I do.
Harry: No you don’t.
Sally: Yes I do.
Harry: You only think you do.
Sally: You say I’m having sex with these men without my
knowledge?
Harry: No, what I’m saying is they all WANT to have sex with
you.
Sally: They do not.
Harry: Do too.
Sally: They do not.
Harry: Do too.
Sally: How do you know?
Harry: Because no man can be friends with a woman that he
finds attractive. He always wants to have sex with her.
Sally: So, you’re saying that a man can be friends with a
woman he finds unattractive?
Harry: No. You pretty much want to nail ’em too.
Sally: What if THEY don’t want to have sex with YOU?
Harry: Doesn’t matter because the sex thing is already out
there so the friendship is ultimately doomed and that is the end of the story.
Sally: Well, I guess we’re not going to be friends then.
Harry: I guess not.
Sally: That’s too bad. You were the only person I knew in New York.

Here’s an abstract from a recent meeting of the Human Behavior and Evolution Society (no online paper that I could find):

Getting Both Sides of the Story: Sexual Attraction and Sexual Events
Between Opposite-Sex Friends

Matteson, Lindsay K. (University of Wisconsin-Eau Claire,
[email protected]); Gragg, Brittany I.; Stocco, Corey S.; Bleske-Rechek, April

Debate exists on whether opposite-sex friends experience sexual
attraction to one another and, if so, whether that attraction adds
spice or strife to the friendship. Little systematic research,
however, has evaluated these questions; and existing studies have not
asked for both friends’ perspectives. In the current study, 89 pairs
of young adult opposite-sex friends (mean friendship duration = 2
years) reported on their friendship. Men reported more sexual
attraction to their friends than did women, and this sex difference
endured after controlling for men’s greater sexual unrestrictedness.
Approximately 25% of friendship pairs had romantically kissed, and
over 10% had "fooled around." Attraction to friend was not related to
friendship duration, and sexual events occurred at various time
points in the friendship, suggesting that attraction to friends isn’t
something that is "overcome" with time. We discuss our findings in
the context of mainstream literature suggesting that opposite-sex
friendships are inherently platonic.