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/