I'll admit it: I am confused about genetics and heritability. Not about the results of the various twin studies - Scott summarises them as "~50% of the variation is heritable and ~50% is due to non-shared environment", which seems generally correct.

But I am confused about what this means in practice, due to arguments like "contacts are very important for business success, rich people get much more contacts than poor people, yet business success is strongly correlated with genetic parent wealth" and such. Assuming that genetics strongly determines... most stuff... goes against so many things we know or think we know about how the world works. And by "we" I mean lots of different people with lots of different political views - genetic determinism means, for instance, that current variations in regulation and taxes are pretty unimportant for individual outcomes.

Now, there are many caveats about the genetic results, particularly that they measure the variance of a factor rather than its absolute importance (and hence you get results like variation in nutrition being almost invisible as an explanation for variation in height), but it's still hard to figure out what this all means.

Then we have Scott's latest post, which points out that "non-shared environment" is not the same as "nurture", since it includes, for instance, dumb luck.

However, "heritable" is not the same as as "nature", either. For instance, sexism and racial prejudices, if they are widespread, come under the "heritable" effects rather than the "environment" ones. And then it gets even more confusing.

Widespread prejudice is not "environment". Rarer prejudice is.

For instance, imagine that we lived in a very sexist society where women were not allowed to work at all. Then there would be an extremely high, almost perfect, correlation between "having a Y chromosome" and "having a job". But this would obviously be susceptible to a cultural fix.

Obviously racial effects can have the same effect. It covers anything visible. So a high heritability is compatible with genetics being a cause of competence, and/or prejudice against visible genetic characteristics being important ("Our results indicate that we either live in a meritocracy or a hive of prejudice!").

Note that as prejudices get less widespread, they move from showing up on the genetic variation, to showing up in the environmental variation side. So widespread prejudices create a "nature" effect, rarer ones create a "nurture" effect. Evenly reducing the magnitude of a prejudice, however, doesn't change the side it will show up on.

Positional genetic goods: Beauty... and IQ?

Let's zoom in on one of those visible genetic characteristics: beauty. As Robin Hanson is fond of pointing out, beautiful people are more successful, and are judged as more competent and cooperative than they actually are. Therefore if we have a gene that increases both beauty and IQ, we would expect it's impact on success to be high. In the presence of such a gene, the correlation between IQ and success would be higher than it should objectively be. This suggest a (small) note of caution on the "mutation load" hypotheses; if reducing mutation load increases factors such as beauty, then we would expect increased success without necessarily increased competence.

But is it possible that IQ itself is in part a positional good? Consider that success doesn't just depend on competence, but on social skills, ability to present yourself well in an interview, and how managers and peers judge you. If IQ affects or covaries with one or another of those skills, then we would be overemphasising the importance of IQ in competence. Thus attempts to genetically boost IQ could give less impact than expected. The person whose genome was changed would benefit, but at the (partial) expense of everyone else.

Do people know of experiments (or planned experiments) that disentangle these issues?

Title:

Emergence of good conduct, scaling and Zipf laws in human behavioral sequences in an online world

Abstract:

We study behavioral action sequences of players in a massive multiplayer online game. In their virtual life players use eight basic actions which allow them to interact with each other. These actions are communication, trade, establishing or breaking friendships and enmities, attack, and punishment. We measure the probabilities for these actions conditional on previous taken and received actions and find a dramatic increase of negative behavior immediately after receiving negative actions. Similarly, positive behavior is intensified by receiving positive actions. We observe a tendency towards anti-persistence in communication sequences. Classifying actions as positive (good) and negative (bad) allows us to define binary 'world lines' of lives of individuals. Positive and negative actions are persistent and occur in clusters, indicated by large scaling exponents alpha~0.87 of the mean square displacement of the world lines. For all eight action types we find strong signs for high levels of repetitiveness, especially for negative actions. We partition behavioral sequences into segments of length n (behavioral `words' and 'motifs') and study their statistical properties. We find two approximate power laws in the word ranking distribution, one with an exponent of kappa-1 for the ranks up to 100, and another with a lower exponent for higher ranks. The Shannon n-tuple redundancy yields large values and increases in terms of word length, further underscoring the non-trivial statistical properties of behavioral sequences. On the collective, societal level the timeseries of particular actions per day can be understood by a simple mean-reverting log-normal model.

Link:

http://arxiv.org/abs/1107.0392

Popular science interpretation:

The way patterns of behaviour emerge and spread through society is the subject of intense research at the moment.

[...] behaviours spread from one network to another, for example, an angry phone conversation can affect the next email you write.

Today, Stefan Thurner at the Santa Fe Institute in New Mexico and a couple of pals [...] study the patterns of behaviour that emerge in a virtual world where every interaction is recorded for posterity.

The world they've chosen is a massive multiplayer online game called Pardus, which started in 2004 and today has some 380,00 players.

Thurner and co studied eight basic actions in which players interact with each other. These are: communication, trade, establishing or breaking friendships and enmities, attack and punishment. They simply recorded the stream of actions that each player performs and then looked for patterns that occur more often than expected.

Their conclusions are straightforward to state. Thurner and co found that positive behaviour intensifies after an individual receives a positive action.

However, they also found a far more dramatic increase in negative behaviour immediately after an individual receives a negative action. "The probability of acting out negative actions is about 10 times higher if a person received a negative action at the previous timestep than if she received a positive action," they say.

Negative action is also more likely to be repeated than merely reciprocated, which is why it spreads more effectively.

So negative actions seem to be more infectious than positive ones.

However, players with a high fraction of negative actions tend to have shorter lives. Thurner and co speculate that there may be two reasons for this: "First because they are hunted down by others and give up playing, second because they are unable to maintain a social life and quit the game because of loneliness or frustration."

So the bottom line is that the society tends towards positive behaviour.

[...] it opens a new front in the study of the human condition and the origin of good and bad behaviour.

[...]

"We interpret these findings as empirical evidence for self organization towards reciprocal, good conduct within a human society," they say.

[...] (popsci author note) Maybe. More interesting will be a next generation of studies that examine how small changes in environmental conditions can lead to big changes in behaviour.

Link:

http://www.technologyreview.com/blog/arxiv/26967/