Free University of Brussels, Brussels, Belgium.
Proc Biol Sci. 2011 Jun 7;278(1712):1697-704. doi: 10.1098/rspb.2010.2084. Epub 2010 Nov 17.
Mechanisms related to collective decision making have recently been found in almost all animal reigns from amoebae to worms, insects and vertebrates, including human beings. Decision-making mechanisms related to collective movements-including pre-departure and joining-have already been studied at different steps of the movement process, but these studies were always carried out separately. We therefore have no understanding of how these different processes are related when they underlie the same collective decision-making event. Here, we consider the whole departure process of two groups of Tonkean macaques (Macaca tonkeana), using a stochastic model. When several exclusive choices are proposed, macaques vote and choose the majority. Individuals then join the movement according to a mimetism based on affiliative relationships. The pre-departure quorum and the joining mimetic mechanism are probably linked, but we have not yet identified which transition mechanism is used. This study shows that decision-making related to macaque group movements is governed by a quorum rule combined with a selective mimetism at departure. This is the first time that transition mechanisms have been described in mammals, which consequently helps understand how a voting process leads to social amplification. Our study also provides the first complete proof that there is continuity in the decision-making processes underlying collective movements in mammals from the first intention movement right through to the last joiner.
最近，从变形虫到蠕虫、昆虫和脊椎动物，包括人类在内，几乎所有动物王国都发现了与集体决策相关的机制。与集体运动相关的决策机制——包括出发前和加入——已经在运动过程的不同阶段进行了研究，但这些研究总是分开进行的。因此，当这些不同的过程是同一集体决策事件的基础时，我们并不了解它们是如何相互关联的。在这里，我们使用随机模型来考虑两组东加长尾猕猴（Macaca tonkeana）的整个出发过程。当提出几个排他性选择时，猕猴会投票并选择多数。然后，个体根据基于亲和关系的模仿行为加入运动。出发前的法定人数和模仿的加入机制可能是相关的，但我们还没有确定使用哪种过渡机制。这项研究表明，与猕猴群体运动相关的决策是由一个法定人数规则和出发时的选择性模仿相结合来控制的。这是首次在哺乳动物中描述过渡机制，这有助于理解投票过程如何导致社会放大。我们的研究还首次完整地证明了哺乳动物的集体运动决策过程具有连续性，从最初的运动意图到最后一个加入者。
