OutGroup

Aftermath of the fight: The consequences of out-group conflict Professor of Behavioural Ecology, Andy Radford, heads up a five-year project at the University of Bristol, investigating the impact for social animals of out-group conflict. The study seeks to uncover short and long-term effects for groups of confrontations with outsiders Whilst there are many published studies on the effects of fighting within groups of animals, the lasting consequences of conflicts with outsiders (rival individuals or groups) has received relatively little scientific attention. However, these consequences of out-group conflict have deep relevance for our understanding of biology, anthropology, economics and psychology, as well as the social and political sciences.

In a wide range of social species, including various insects, birds, fish and of course humans, there is an investment into acquiring and defending resources to survive. Battles with out-groups over these resources have knock-on effects for all involved in the immediate aftermath, but also in the longer term and for future generations.

Andy Radford and his team, in collaboration with other universities, are conducting experiments with wild populations of dwarf mongooses and macaques, captive cichlid fish, and humans.

Combining these with theoretical approaches, they endeavor to reveal effects of out-group conflict on: individuals, within-group interactions and decisionmaking, stress, social and reproductive health, and the evolution of weaponry, fortification, cooperation and punishment.

Introducing intruders “Experimental manipulations allow us to isolate the factors that are important, by controlling potential confounding effects, and thus to work out the true impacts of outgroup conflict,” explains Radford. “Using dwarf mongooses and cichlids as model study systems gives us a complementary approach. We work with the mongooses in their natural habitat, so you gain ecological validity but lose a level of control over everything. Whereas an advantage with the captive cichlid experiments is that there is more control of their environment and what goes on around them.

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“With the cichlids, we give a group its own territory in the form of a tank. We then set tanks in ‘neighbourhoods’ so certain groups can see each other. The neighbours are rivals and they can recognise individuals visually,

interested in is whether there are changes in behaviour among the territory-holders in the immediate aftermath of an intrusion, and whether that is affected by the identity and the number of intruders.”

Experimental manipulations allow us to isolate the factors that are important, by controlling potential confounding effects, and thus to work out the true impacts of out-group conflict although they are in separate water. We then carry out simulated intrusions: you can put a transparent divider in a tank and introduce an intruder whenever you want, and then take the intruder away. What we are currently

The research is in its early days, being one year into the five-year study, but the aim is not only to consider short-term effects of single intrusions, but also the long-term implications of repeated intrusions.

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The impacts of fighting out-groups

How does this relate to humans?

Out-group conflict has a range of potential consequences for an animal.

There can be direct effects such as mortality, injury, or loss of resources or reproductive position. Lesser direct impacts arise from the investment of time and energy during the contest, which are traded off against finding food or parental care. Moreover, a fighter may be rewarded for defending the group territory by those that didn’t take part, while individuals that should have taken part might be punished to try to ensure that next time they make a stand.

“It does not have to be you involved in the contest – there are consequences for all individuals in the group, including offspring yet to be born. We can examine this possibility with the cichlids, because they will breed in captivity and so you can count the number of eggs, remove them to take various measurements or even raise them separately to investigate maternal effects. If mothers are stressed, what goes into their eggs might differ, so it’s possible there is an effect on how offspring develop. Moreover, there might be changes in how quickly parents produce the next clutch depending on the frequency of intrusions by outsiders.”

Monitoring in this way will show how out-group conflict can have longer lasting impacts, including those for subsequent generations and, ultimately, evolutionary processes. Such considerations are particularly relevant in a world of shrinking habitats where animal groups are competing for limited resources.

Whilst the study is primarily focusing on non-human animal behaviour postconflict, there are undeniable parallels with humans. As a warring society, can the research be relevant for understanding human nature better?

“Fundamentally, wars are about resources such as oil fields or food; even religious sites can be viewed as a resource – it’s the same principle,” observes Radford. “If you talk about primitive human warfare in ancestral societies then there are lots of parallels, but modern warfare is complicated by the fact commanders are nowhere near the frontline – they direct pawns and longrange weapons from far away.”

The study has more common ground with conflict between smaller groups than whole nations. For instance, the team are starting collaborative work with psychologists investigating street fights after pubs close or instances of shoplifting (where the criminal is the outsider, and shop workers and customers have different levels of investment in the resource).

“We’re also starting to consider work on mothers and toddlers, and the cliques that form in group settings. There can be conflict between toddlers fighting over a toy or a mother being nasty to another mother, and we’re interested in the aftermath effects and interactions.”

Conflict with out-groups has significant effects for us, as much as any social animal, so the project’s work will produce data and knowledge that could have a wide range of applications.

At a glance Full Project Title Consequences of out-group conflict (OutGroup) Project Objectives The aim of this project is to determine the proximate and ultimate consequences of a fundamental but neglected aspect of sociality: out-group conflict. In a wide range of social species, from ants to humans, group members invest considerable defensive effort against individual intruders and rival groups. The lasting impacts of these conflicts with conspecifics are poorly understood. We will integrate empirical and theoretical approaches to uncover the effect of out-group conflict on: (i) individual behaviour, within-group interactions and group decisionmaking; (ii) steroid hormones that underlie stress, social behaviour and reproduction; (iii) variation in reproductive success arising from maternal investment and offspring care; and (iv) the evolution of societal structure, cooperation and punishment among group-mates, and weaponry and fortification.

ERC Team Members Dr Ines Goncalves, Dr Julie Kern, Amy Morris-Drake and Dr Susanne Schindler.

Project Funding ERC Consolidator Grant Contact Details School of Biological Sciences University of Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ T: +44 117 394 1197 E: andy.radford@bristol.ac.uk W: http://www.bio.bris.ac.uk/research/behavior/ Vocal_Communication/research.html

Professor Andy Radford, Ph.D

Photograph by Shannon Benson Professor Andy Radford, Ph.D did his first degree at the University of Cambridge (Girton College, Zoology BA Hons, 1996), then completed a Masters at the University of Oxford (New College, Biology: Integrative Bioscience MSc, 1998). He returned to the Department of Zoology (and Girton College) in Cambridge to conduct his PhD under the supervision of Professor Nick Davies FRS, which he obtained in 2003, when his thesis was examined by Professors Tim Clutton-Brock FRS and Ben Hatchwell. By that stage, he was a Junior Research Fellow at Girton College, a position he occupied until 2005. In 2005 he was awarded a BBSRC David Phillips Research Fellowship, which he moved to Bristol in 2006 to take up a proleptic lectureship in the School of Biological Sciences. He was promoted to a Readership in 2012 and became Professor of Behavioural Ecology in 2016.

www.euresearcher.com

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