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Study shows that war profiteers fuel conflicts

International research team investigates the readiness of groups to engage in violence and conflict in behavioural experiments / Publication in ‘Nature Human Behaviour’

Those who profit more from a raid than other individuals in their group fuel conflicts with opponents – even if this endangers the well-being of their own group. That is the result of behavioural experiments a research team from Cologne, Marburg, and Toulouse carried out with Ethiopian semi-nomads. The results of their research have been published in the current online edition of ‘Nature Human Behaviour’.
For most people, there is more to lose than to gain in violent conflicts. Nevertheless, such disputes occur time and again. ‘The rule according to which spoils are divided among victorious groups has a strong influence on individual willingness to get involved in conflicts’, explains Dr Hannes Rusch, an economist at Philipps-Universität Marburg who co-authored the study.

Rusch conducted the experiments together with Junior Professor Dr Gönül Doğan from the University of Cologne and anthropologist Dr Luke Glowacki from Toulouse. Two aspects were essential: What influence do distribution rules have on the willingness of individuals to stand up for their own group in a conflict? How relevant are such material incentives when groups with a hostile history meet? To answer these questions, the research team conducted an economic experiment with three Ethiopian population groups. Two of these communities share a long history of violent hostilities. However, peaceful trade relations exist between these two groups and a third local group.

Around 200 members of these ethnic groups took part in a model conflict game. ‘The historical enmity between the ethnic groups only has a measurable influence on decision-making behaviour if the booty is divided equally within the winning group’, explains Gönül Doğan. ‘In this case, the participants mainly chose defensive strategies.’ A different picture arises when the winners divide their booty unequally among themselves. In this case, the disadvantaged group chooses defensive strategies while the profiteers show offensive-aggressive behaviour. ‘The history of the population groups plays no measurable role here’, says Luke Glowacki from the Institute for Advanced Study in Toulouse.
‘Our results shed new light on violent clashes between groups’, Rusch is convinced. ‘If some group members benefit more strongly from such conflicts, it can be precisely these profiteers who become particularly aggressive. Often enough, this may suffice to set the spiral of violence and counter-violence in motion.’

Dr Gönül Doğan is junior professor at the University of Cologne’s Seminar for Corporate Development and Business Ethics. Dr Hannes Rusch is a member of the Working Group Financial Science at Philipps-Universität Marburg. The anthropologist Dr Luke Glowacki is a visiting scholar at the Institute for Advanced Study in Toulouse. The research project was funded by the Dr. Jürgen Meyer Foundation and other third parties.

Original publication:
Gönül Doğan, Luke Glowacki & Hannes Rusch: Spoils division rules shape aggression between natural groups, Nature Human Behaviour 2018, DOI:

Media Enquiries:

Junior Professor Dr Gönül Doğan
Seminar for Corporate Development and Business Ethics
University of Cologne
+49 221 470-4051

Dr Hannes Rusch
Working Group Financial Science
Philipps-Universität Marburg
+49 6421 28-23178

Press and Communications Team:

Jan Voelkel
University of Cologne
+49 221 470-2356