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Session 15: Conflict Negotiation

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Author: Agustin Fuentes
Primate conflict and post-conflict theories. Case studies of macaque and chimpanzee social organization.

1.  Key Concepts:

Conflict occurs in all groups of living organisms, and primates are no exception.  Typically, conflicts and aggression arise over access to limited resources, such as food or mates.  Resolving this conflict in a manner able to maintain group cohesion is important for future group dynamics.  According to Arnold and Aureli, "behavioral mechanisms that mitigate conflict, prevent aggressive escalation, and resolve disputes should have been strongly selected in group-living animals."

2.  Terms & Definitions:

Selfish gene
The idea that DNA, or specifically genes, competes for limited space and resources to produce more of their own kind.
The act of intervening for the purpose of bringing about a settlement.

3.  Current Paradigms in the Evolution of Behavior Surrounding Conflict:

Why Cooperate?  Understanding cooperative and potentially altruistic behaviors have long been of interest to evolutionary biologists.  Several shifts in the focus of research have occurred recently.  These focus on:

  • “Selfish gene”/Individualistic focus: cooperation only as response to selfish propagation.
  • Focus on specific conflicts, not a lifetime of cooperation.
  • Cooperation and affiliation have evolved to deal with damage, or costs, caused by conflict.
“Who is the fittest? Those that are continually at war with each other, or those who support one another?…those animals which mutually acquire aid are undoubtedly the fittest.”
--Prince Petr Krapotkin, in Mutual Aid (1908)

Other Options?

  • Long term relationships and cooperation as core to behavioral patterns.
  • Non-functional behaviors occur.
  • Selection favoring behavioral flexibility rather than specific selection for behaviors related to conflicts.
  • Multi-level selection (Wilson and Sober) focuses on what is favored if we looks at groups as units of selection.

4.  A Brief History of Aggression and Post-conflict Studies:

What happens after conflicts?  If a bond is important, because of social status, hierarchy, or group dynamics, the bond must be remedied or reconciled.  Research into this area has shifted through the decades.

  • A Focus on Aggression 1950s-1960s.
  • A Focus on Conflict 1970s-1980s.
  • A Focus on Post-conflict Behavior and Reconciliation 1980s-1990s.
  • Today: Conflict Negotiation, Valued Relationships, Uncertainty Reduction, Mediation and Consolation.

Frans de Waal:  Pioneer in the study of Post Conflict Behavior

“Evolutionary approaches to animal social behavior have been dominated by a false dichotomy between aggression and sociality.  Struggle-for-life language was directly transferred to the social domain resulting in an overemphasis on clashing individual interests. Theorists insisted on cost-benefit analysis, whereas in reality benefit-benefit arrangements seemed quite common.  The possibility of shared interests was so far from the minds of evolutionary biologists (except with regard to kin) that when it came to the accounting for the rarity of lethal violence, rather than assuming a need for cooperation and stable group life, explanations focused exclusively on the physical risks of combat.”

- de Waal 2000

Aggression as anti-social tendency model (Lorenz on through 70s)

  • Dispersal: aggression reduces interaction/association/proximity.
  • Motivational continuity: post-conflict contact is residual antagonism.
  • Bonding excludes aggression: aggression is rare amongst socially close and cooperative individuals.

Relational model (in part influenced by McKenna’s early work)

  • Social repair—increased friendly contact post-aggression, esp. between opponents.
  • Motivational shift: post-aggression contact can be unusually intensive.
  • Conflict as negotiation: aggr. and post-conflict contact common among socially close and cooperative individuals.
  • Calming effect: post-conflict contact reduces anxiety and restores tolerance.

De Waal’s relational model:

Conflict is resolved if there is a conflux of interest.

There are three ways to deal with conflict of interest: tolerance, aggression, and avoidance.

5.  Reconciliation:

Peaceful post conflict contact:  what is it?

  • Reconciliation--“without denying the human heritage of aggression and violence, this research demonstrates an equally old heritage of countermeasures that protect cooperative arrangements against the undermining effects of competition." —de Waal, 2000
  • Uncertainty Reduction—“Although we have studied peaceful post-conflict behavior in dozens of species, we do not yet have enough information about its form, pattern, and function to draw firm conclusions about the selective forces that have shaped its evolution.” —Silk, 2000

Primary Thesis of Most Post-Conflict Research:

Post-conflict behavior, especially reconciliation, is functional and has evolved as a response to curtail the damage caused by conflict.  Reconciliation is defined as peaceful post-conflict contact and assumed to have a restorative, functional role.

Still awaiting answers...:

  • Are post-conflict behaviors the result of direct selection?
  • Are there uniform sets of post-conflict behavior?
  • Can post-conflict behavior be “uncoupled,” as a unit to be selected, from ongoing behavioral complexes that characterize individual and group relationships?

6.  Measuring reconciliation:

How do post-conflict behaviors compare with baseline, normative behaviors?  If post-conflict behavior is different from pre-conflict behavior, it signals reconciliatory behavior.

Post Conflict/Matched Control methodology:

  • “attracted” vs. “dispersed”(and “neutral”) pairs.
  • null hypothesis: “attracted” = “dispersed.”
  • conciliatory tendency (CT or reconciliation)= % of total pairs that are “attracted.”
  • Corrected conciliatory contact= #attracted pairs vs. # dispersed pairs (more accurate representation of reconciliation).

Why did reconciliation evolve?

“Aggressive conflicts among valuable partners, although they may be rare, are unavoidable.  Given the dynamic nature of relationships, it is critical for one or both partners to establish whether conflict signifies a growing mismatch in the assessments of each other's value or whether it is a mere hiccup in an otherwise unchanged relationship.”  van Schaik and Aureli, 2000

Social benefits exchanged in valuable relationships:

x x x
Alliances for Intragroup contest for resources x (food) x x (mates)
Tolerance at Resources x x x?
Infant care and Protection against Infanticide x x
Alliances/Protection against Harassing males x x
Alliances/Protection against predators/other groups
x x
Mating privileges x?
Alliances against extra-group males x

from van Schaik and Aureli, 2000.

But not all conflicts are reconciled.  In fact, in many species very few conflicts are reconciled.  Why?

  1. Relationship Qualities: [Cords and Aureli á la Hinde (content and patterning) and Kummer (social investment)]
    1. Value: level of overall benefits derived form association and accessibility of partner.
    2. Security: perceived probability of partner’s consistency in behavioral patterns.
    3. Compatibility: the “tenor” of social interactions between the dyad.  Resulting form both “temperament” and history of social exchanges.
  2. Valuable partners and reconciliation:
    1. ↑value = ↑likelihood of reconciliation.
    2. ↓security = ↑likelihood of reconciliation.
    3. ↑compatibility= ↑likelihood of reconciliation.

Can we measure these things?

  1. Value--what factors impact it?  How do individuals measure it?
  2. Security--social patterns? Stress response?
  3. Compatibility--frequency and type of behavioral interactions, “friendships”

Why review Nonhuman Primate and Human data?

Primate-wide patterns indicate common ancestry and offer insight into evolved/evolving patterns of behavior.  Aggression and reconciliation are important culturally for humans and understanding their patterns facilitates cultural modification and/or contextualization.  Without data we are just hypothesizing endlessly.

7.  Macaques as comparative tools?

Macaques utilize a vast amount of reconciliatory behaviors.  Of the macaques, M. mulatta reconciles the least.  This is due to their maintatined, strict hierarchy.  This lessens the need for conciliatory behaviors.  Reasons for understanding why macaques are a good model for humans follow:

  • Pliocene-pleistocene radiation, along with genus Homo.
  • Generalized social group with complex and variable intra-individual social relationships, heavily reliant on alliances and coalitions.
  • Diverse immune response systems.
  • Variable CT across species and within species (7-53%).

Thierry’s “grades” of macaque social organization:

1 2
M. Mulatta
M. fascicularis M. sylvanus
M. nigra
Conciliatory tendency, social tolerance-------------->              
<------------ Asymmetry, dominance, kin bias

Co-variation of traits:

  • ↑social tolerance/affiliation = ↓asymmetry of dominance interactions, which also = ↑CT.
  • ↑ kin bias = ↑ asymmetrical dominance = ↓ CT.
  • Single trait co-variation:
    • “bared teeth” display across species, changing “meaning” in different social venues
    • Power asymmetry and social styles

    SO WHAT? Understanding how conflict negotiation systems “work” in a comparative context

    • Predictable patterns tied to social styles.
    • Intra-specific variation tied to context and social instability.
    • Ecological factors.
    • Phylogenetic inertia.

    Physiology of dominance and possible roles for conflict negotiation? (Sapolsky)

    • Dominance relationships and physiological stress affected by quality of life in a group (social “styles”).
    • Dominance relationships and physiological stress affected by Phylogenetic patterns (species-wide patterns).
    • Dominance relationships and physiological stress affected by ontogeny (life experience).
    • All tie directly to the patterns of “conflict negotiation.”


Macaques as model can be good in some cases.  Macaque conflict negotiation in primate context provides broad comparative dataset and potential predictive patterns for co-variation of traits.  Could Macaque conflict negotiation reflect components of the human system?

8.  Chimpanzees as comparative tools:

Chimpanzees are often touted as appropriate comparative models for several reasons.  They are considered by many experts in the field to be "master reconcilers" who exhibit a distinct and quantifiable set of reconciliatory behavior (de Waal).  Additional reasons to study chimpanzees as models for understanding conflict and reconciliation in humans include:

  • Phylogenetic sister taxa
  • Similarities in social complexity
  • Potential to identity Hominoid/Hominine traits

Study at the Chimpanzee and Human Communications Institute (CHCI) at Central Washington University (Fuentes):

  • 5 adult chimpanzees (Pan troglodytes).
  • 3 females, 2 males.
  • Stable social group since 1981.
  • In present enclosure since 1993.
  • 840 hours of data 255 conflicts (262 conflict pairs).
  • 6 six-week collection periods 1997-2000.

Conflict data

(219 conflicts 1998-2000… 224 conflict pairs)

  • 83 level 1 (threats, no contact).
  • 129 level 2 (hits/kicks).
  • 12 level 3 (prolonged grappling).
  • 0 level 4 (serious injury) (none during observation periods).
  • Conflicts ranged between 2-120 seconds, with a mean duration of 15 seconds.

Distribution of conflicts by individual:

Piechart showing conflicts by individual

Distribution of Conflicts by Setting at the CHCI 1998-2000:

Piechart showing conflict distribution by setting

Chimpanzee Reconciliation:

Species Location/Setting Group Size Opponent Pairs Reconciliation Corrected Conciliatory Tendency
Pan troglodytes Arhem1
Indoor, 1979 20 150 34.7% ---
Outdoor, 1979 20 200 29.5% ---
Outdoor, 1981 20 95 26.6% ---
Indoor/Outdoor, 1994 11 43 49.7% 14.4%
Indoor/Outdoor, 1997-2000 5 262 25.15 17.25%
Free ranging, Uganda 51 120 19.2%
Outoor 16 401 44.8% 41.2%
Pan paniscus San Diego Zoo6
Indoor/Outdoor, 1987 6 333 43.8% ---
Outdoor, 1997 4 179 55.9% ---


1. de Waal and van Roosmalen 1979, Griede 1981

2. Baker and Smuts 1994

3. Fuentes et al. 2002

4. Arnold and Whitten 2001

5. Preuschoft et al. 2002

6. de Waal 1987

Individual CCTs at CHCI:

Dar Loulis Moja Tatu Washoe
Dar (8.1%) 90 (4.4%) 5 (20%) 13 (30.8%) 3 (0%)
Loulis (6.4%) 9 (33%) 50 (10%) 78 (3.8%)
Moja (32%) 8 (37.5%) 3 (33%)
Tatu (17.6%) 3 (33%)
Washoe (5.8%)
Yerkes: Individual CCT 20-69%

CCT by ages/sex class:

Ages/sex class CHCI Yerkes
AM-AF 16.3% 45.7%

Other Post-conflict Behavior at the CHCI:

Post-Conflict Matched Control PC vs. MC (Chi Square)
Consolation 40.0% 35.9% NS
Redirection 30.5% 8.0% p < .01
Proximity (closer sooner) 67.2% 31.7% p < .01
Maintenance of Visual Contact 79.1% 64.6% p < .01

1997 - 2000 Post-Conflict Behavior (+=p<0.01):

Dar Loulis Moja Tatu Washoe Group
Agonism 3
Affinitive Social 1,4 2
Bad Observation 4 5
Coprography 2,3,5 2,3,5
Display 1,2,3,5,6 2,3,5,6 1,2,3,5,6
Feeding 6 1,6 3 6
Groom 3 4 4
Play 4 1 1,4
Object Manipulation 3 4 2 3,4,6 3,4
Other 5 2 2
Reassurance 3 3
Self-groom 3,5,6 3,4,5 1 3 6 3,5,6
Threat 5 1,2,4,5,6 3 1,2,5,6 1,2,4,5,6
Travel 2 1,4 3 1,2,4

Pre-Conflict Behavior at the CHCI: (John Mulcahy and A. Fuentes)

  • Pre-Conflict: higher affiliative, threat and travel, and lower feed, object use and self-groom behaviors.
  • Closer together (reduced inter-individual distances) in pre-conflict period when visitors are present.
  • Pre-conflict negotiation?
  • Significant individual differences in pre-conflict behavior amongst the group members.

ASL use?

  • No significant change in their ASL use patterns in post-conflict periods.

Chimpanzee conclusions:

  • We still know very little about chimpanzee post-conflict behavior.
  • No clear and distinct set of reconciliatory behaviors.
  • Most data comes from captive groups.
  • There is a strong individual component.
  • Evidence suggests females reconcile more.

9.  Summary Concepts:

Reconciliation may not be universal or necessarily the primary response to conflict.  Cooperative relationships and relationship history may tell us more about what types of behaviors may arise around conflict than a focus primarily on post-conflict analyses.  A focus on individual variation and behavioral flexibility may offer greater insight into understanding the range of behavioral responses to conflict

What if rather than having evolved a set of specific behavioral responses to repair the damage caused by conflict, inter-individual patterns of cooperation and affiliative relationships might be important causal factors behind observed post-conflict behavior?

What about us?

  • In what ways (if any) do we behave like other primates when reconciling/negotiating conflicts?
  • What elements of human conflict and human conflict negotiation are “primate” and which are “human”?
  • Is there a “biology” of conflict negotiation?

10.  Additional Material:

Required Reading:

Primates in Perspective. 2007.  C.J. Campbell, A. Fuentes, K.C. MacKinnon, M. Panger, S.K. Bearder.  Oxford University Press.

Chapter 36: Postconflict Reconciliation - Arnold and Aureli

Chapter 39: Cooperation and Competition in Primate Social Interactions - Sussman and Garber

Suggested Reading:

de Waal, F.B.M.  (2000).  "Primates--a natural heritage of conflict resolution."  Science.
de Waal, F.B.M.  (2000).  "The first kiss: foundations of conflict resolution research in animals."  In: Aureli, F. and de Waal, F.B.M. (eds.), Natural Conflict Resolution.  University of California Press, Berkeley.  pp. 15-33.

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