158
8 How Society Works
Surprisingly, however, when individuals interact with a small number of neighbors, clusters of people who adopt the same kind of behavior emerge (see Fig. 8.1).
The fact that “birds of a feather flock together”
10 makes a big difference. It allows
moralists to thrive! While cooperators still make lower profits than defectors, moralists, who cooperate and punish uncooperative behavior of others, can now succeed.
This is due to the fact that the different types of behavior are separated from each other
in space. In particular, moralists (shown in green in Fig. 8.1) tend to be separated
from cooperators (shown in blue) by defectors (shown in red). At the boundaries of
their respective clusters, both of them have to compete with non-cooperative agents
(yellow or red). While cooperative agents are exploited by non-cooperative ones,
moralists sanction non-cooperative behavior and can, therefore, succeed and spread.
This is amazing! While random interactions cause a “tragedy of the commons”
where nobody cooperates and nobody makes a profit, we find just the opposite result
if people interact with their neighbors in space or in a social network, where the same
behaviors tend to cluster together. Therefore, a small change in the way interaction
partners are chosen can create conditions under which moral behavior can prevail
over free-riding.
8.7 Containing Crime
Nevertheless, punishing each other is often annoying or inefficient. This is one of
the reasons why we may prefer to share the costs of punishment, by jointly investing
in sanctioning institutions such as a police force or court. This approach is known as
“pool punishment”. A problem with this strategy, however, is that police, courts and
other sanctioning institutions may be corrupted. In addition, it is sometimes far from
clear who deserves to be punished and who is innocent.
11 For the legitimacy and
acceptance of such institutions, it is important that innocent people are not punished
in error. This means that extensive inspections and investigations are required, which
can be costly compared to the number of people who are finally convicted.
In 2013, Karsten Donnay, Matjaz Perc
12 and I developed a computer model to
simulate the spread and fighting of criminal behavior. We were astonished to find that
greater deterrence in the form of more surveillance and higher punishment would not
eliminate crime.
13 People don’t just make a calculation whether crime pays off or
not, as is often assumed. Instead, crime is kind of “infectious”, but punishment and
10 A phenomenon that sociologists call “homophily”.
11 US death row study: 4% of defendants sentenced to die are innocent, see http://www.thegua
rdian.com/world/2014/apr/28/death-penalty-study-4-percent-defendants-innocent; also see Elite
FBI forensic unit gave flawed testimony, see http://www.cbsnews.com/news/fbi-hair-analysis-err
ors-led-to-convictions-new-report-finds/.
12 Perc et al. [7].
13 In fact, crime rates are not lower, although the prison population in the USA is almost 10 times
higher than in Europe, see the list of countries by incarceration rate, http://en.wikipedia.org/wiki/
List_of_countries_by_incarceration_rate#Incarceration_rates.
8 How Society Works
Surprisingly, however, when individuals interact with a small number of neighbors, clusters of people who adopt the same kind of behavior emerge (see Fig. 8.1).
The fact that “birds of a feather flock together”
10 makes a big difference. It allows
moralists to thrive! While cooperators still make lower profits than defectors, moralists, who cooperate and punish uncooperative behavior of others, can now succeed.
This is due to the fact that the different types of behavior are separated from each other
in space. In particular, moralists (shown in green in Fig. 8.1) tend to be separated
from cooperators (shown in blue) by defectors (shown in red). At the boundaries of
their respective clusters, both of them have to compete with non-cooperative agents
(yellow or red). While cooperative agents are exploited by non-cooperative ones,
moralists sanction non-cooperative behavior and can, therefore, succeed and spread.
This is amazing! While random interactions cause a “tragedy of the commons”
where nobody cooperates and nobody makes a profit, we find just the opposite result
if people interact with their neighbors in space or in a social network, where the same
behaviors tend to cluster together. Therefore, a small change in the way interaction
partners are chosen can create conditions under which moral behavior can prevail
over free-riding.
8.7 Containing Crime
Nevertheless, punishing each other is often annoying or inefficient. This is one of
the reasons why we may prefer to share the costs of punishment, by jointly investing
in sanctioning institutions such as a police force or court. This approach is known as
“pool punishment”. A problem with this strategy, however, is that police, courts and
other sanctioning institutions may be corrupted. In addition, it is sometimes far from
clear who deserves to be punished and who is innocent.
11 For the legitimacy and
acceptance of such institutions, it is important that innocent people are not punished
in error. This means that extensive inspections and investigations are required, which
can be costly compared to the number of people who are finally convicted.
In 2013, Karsten Donnay, Matjaz Perc
12 and I developed a computer model to
simulate the spread and fighting of criminal behavior. We were astonished to find that
greater deterrence in the form of more surveillance and higher punishment would not
eliminate crime.
13 People don’t just make a calculation whether crime pays off or
not, as is often assumed. Instead, crime is kind of “infectious”, but punishment and
10 A phenomenon that sociologists call “homophily”.
11 US death row study: 4% of defendants sentenced to die are innocent, see http://www.thegua
rdian.com/world/2014/apr/28/death-penalty-study-4-percent-defendants-innocent; also see Elite
FBI forensic unit gave flawed testimony, see http://www.cbsnews.com/news/fbi-hair-analysis-err
ors-led-to-convictions-new-report-finds/.
12 Perc et al. [7].
13 In fact, crime rates are not lower, although the prison population in the USA is almost 10 times
higher than in Europe, see the list of countries by incarceration rate, http://en.wikipedia.org/wiki/
List_of_countries_by_incarceration_rate#Incarceration_rates.