Do we look like monkeys when making decisions?

Which leadership strategies work best

We once were monkeys, so it is interesting to understand how monkeys make decisions and how this differs from us. This post is focused on the white-faced capuchin monkeys. They have a very high intelligence, and live in groups of 16 individuals on average, about three quarters of which are females. Both kinship and dominance rank are important organizing factors in the structuring of female-female social relationships. They occupy home ranges of between 32 and 86 hectares, making traveling an important daily activity. Groups of capuchins stay together for live, and thus they need to move collectively. Obviously, this requires cohesion between group members. How do members temper their interindividual differences and how do group members choose the same direction and coordinate their moves?

Two very interesting papers describe the distributed leadership and decision making strategies of white-faced capuchin monkeys:

• Leca, J. B., Gunst, N., Thierry, B., & Petit, O. (2003). Distributed leadership in semifree-ranging white-faced capuchin monkeys. Animal Behaviour, 66(6), 1045–1052.
• Petit, O., Gautrais, J., Leca, J. B., Theraulaz, G., & Deneubourg, J. L. (2009). Collective decision-making in white-faced capuchin monkeys. Proceedings of the Royal Society of London B: Biological Sciences, 276(1672), 3495–3503.

Surprisingly, neither kinship nor dominance rank influences who the leader will be during collective decision making about group movements. Instead, they use a ‘distributed leadership’ strategy.

(1) Several individuals, not necessarily the most dominant ones, can initiate movements
(2) the spatial and temporal distribution of the group affects the probability of a successful travel initiation
(3) the leading individual looks at the responses of others to its own signals.

To initiate a collective movement, an individual will change its behavior to signal to the others he wants to move. Behavioral patterns of the initiator include: trills (loud vocalization that consists of rapid series of pulses, looking backwards and taking short pauses (stop of <10s) during his movement. The most decisive behavior that contributed to successful group movements was looking backwards.

This shows that they rely more on visual than vocal signals.

The more numerous the individuals involved in the decision process, the more communication signals are needed. An initiator is more successful in triggering a group movement when starting from a core position in a clumped group than from an edge position or from a dispersed group.

These is no statistically significant effect of sex on the percentage of start attempts. However, female initiators showed higher percentages of successful attempts than males. There is no significant correlation between hierarchical rank and percentage of start attempts or between hierarchical rank order and the percentage of successful attempts.

The timing of the initiations is very important. More than 90% of the initiations occurs while the group has been together within the initiator’s departure area. One of the conditions for being followed by the whole group is to wait long enough after the previous initiation. An individual making a start attempt too early often fails to induce an immediate following of the group.

If chances to a failed initiation are much higher when you start to early, why would an individual risk to be the first initiator?

There are two apparent advantages of being the first initiator.

(1) The direction that the group eventually will take is most often that proposed by the first moving animal (even when the first attempt failed).

(2) Because leading a group is costly in terms of energy and dangerous in terms of disrupting the cohesion of the group, this individual gains immediate respect from other group members.

In the case of white-faced capuchin monkeys, the collective decision process during group movement is an all-or-nothing outcome: either the whole group departs to another area or the initiation fails.

Apparently the white-faced capuchin monkeys distributed leadership strategy (= everyone can play the role of initiator) is common amongst social organisms; very similar strategies have been found in hamadryas baboons, Tonkean macaques, Brown lemurs, cattle, Prezwalski horses, plains zebras, and geese.

Can we add ourselves to this list?

I would love to see a longterm study on the behavior of a group of humans when it comes to group movement…
Who decides the next move in your startup? Do you see a distributed leadership or an individual leadership? What increases the success rate? Do hierarchical ranks or sex play a decisive role? How does the leader signal to the other group members?

Obviously, we can find many different leadership structures in collective decision-making in our organizations (or in any human context honestly). But are our strategies evolving and will time eventually lead to the best fitting one for the survival of your company?

Intrigued by capuchins?
This is a great documentary about the life of a family of white-faced capuchin monkeys (followed over 20 years by primatologist Susan Perry):

Further Readings

• Norton, G. W. (1986). Leadership decision processes of group movement in yellow baboons. Primate ecology and conservation, 145–156.
• Ramseyer, A., Thierry, B., Boissy, A., & Dumont, B. (2009). Decision making Processes in Group Departures of Cattle. Ethology, 115(10), 948–957.
• Ramseyer, A., Petit, O., & Thierry, B. (2009). Decision-making in group departures of female domestic geese. Behaviour, 146(3), 351–371.
• Bourjade, M., Thierry, B., Maumy, M., & Petit, O. (2009). Decision‐Making in Przewalski Horses (Equus ferus przewalskii) is Driven by the Ecological Contexts of Collective Movements. Ethology, 115(4), 321–330.
• Jacobs, A., Sueur, C., Deneubourg, J. L., & Petit, O. (2011). Social network influences decision making during collective movements in brown lemurs (Eulemur fulvus fulvus). International Journal of Primatology, 32(3), 721–736.
• King, A. J., & Sueur, C. (2011). Where next? Group coordination and collective decision making by primates. International Journal of Primatology, 32(6), 1245–1267.