Why Show Nonverbal Submission?
Christopher Philip

In their 2006 paper Shuichi Matsumura and Thomas Hayden go over some key points as to when and why an animal (or human) might exhibit nonverbal signals of submission.

We take for granted that submission has some value. We usually think of submission as a way to reduce punishment. However, one must wonder, why not simply acquiesce, walk away, or, in extreme cases, flee? Also, why doesn’t the dominant animal simply continue to attack even after they see that the animal has submitted? Why not just oust them altogether?

For a behaviour to be selected for, there need be some benefit to demonstrating it – especially when it is done is such an obvious way.

In their study Shuichi Matsumura and Thomas Hayden set up four basic assumptions for which submissive signals would be favoured including:

(1) when the value of contested resource does not differ greatly from the cost of injury,
(2) when the extra benefit of winning an escalated contest is small,
(3) when the opportunity for safe retreat by the losing animal is small, and
(4) when the estimation of the difference in the resource holding potential (RHP) between the combatants is accurate but not perfect.

They then applied this as a model and programmed it into software to create a game theory for which elements would favour submission signals. They state in their paper that this is the first time any such attempt had been made.

The results bore out their assumptions and provided a set of rules that evolution would favour the display of submissive signals.

The main aim of displaying submissive signals is to resolve conflict in which it is not possible without escalating and when one party is much, or at least slightly weaker, than the other.

The model also showed that signaling submission is expected when the extra benefit for the stronger animal is offset by the cost of escalating the contest and the stronger is satisfied with the acquisition of the resources for which the contest had arisen.

Also, the stronger individual is not expected to deliver submissive signals because their risk of losing is small and their benefit high. Thus, these animals are more likely to choose attack over submit.

How does this game theory apply to humans? In much the same way as it does for animals. We display signals to avoid conflict and set up a method for distributing resources. For people, physical conflict is risky and potentially life threatening. Submission and dominance cues in people is a way we show who deserves what. This may be anything from mates to resources (jobs). Should one party not submit during conflict, then there could be a physical cost and most certainly a social cost. Whether or not we are aware, social hierarchy exists amongst people, and these are normally decided in non-physical ways. Part of this includes nonverbal signals of dominance and submission. When we get on with one another, we decide between us who deserves status and who is next in line.

Resources

Matsumura, Shuichi and Thomas J. Hayden. When should signals of submission be given?–A game theory model. Journal of Theoretical Biology. 2006. 240: 425-433.