Mechanisms and adaptive consequences of group decision-making in a communally nesting bird

解决集体问题是群体生活的核心挑战之一。当个人偏好不同的结果时，社会如何就每个人的选择达成一致？人类群体已经发展出各种各样的方法，从专制到民主投票。动物群体的集体决策不太为人所知，尽管这样的例子比比皆是：蜂群为蜂巢选择一个新位置；一群猴子入侵了邻近的领地；一群鸟改变了栖息的地方。理论模型已经被开发出来，用来预测在什么条件下这些决定应该被分享，以及社会群体的结构和稳定性如何影响这些决定的速度和准确性。然而，对野生动物的实验研究很少，理论预测和经验证据之间存在差距。这个项目探索了一种热带鸟类——大雁的这些缝隙。Anis的巢是由几对组成的社会群体，它们建造一个单一的巢，所有的雌性都在里面产卵。选择在哪里筑巢是一个至关重要的决定，因为它的位置决定了它在捕食者面前的暴露程度。该项目结合了实地实验、行为观察和跟踪技术，以测试群体如何达成共同决策，以及最重要的是，当群体成员不同意时，哪些意见占上风。该项目将为学生和一名博士后研究员提供研究经验，通过一系列公共研讨会为巴拿马研究人员提供培训，并通过与史密森尼热带研究所的合作伙伴关系向公众推广。本项目探讨了最近理论工作中出现的关于集体决策的三个主要问题。首先，随着决策延误的代价越来越高，共同决策是否变得越来越不民主？第二，消息灵通的少数群体能否对群体决策施加不成比例的影响？第三，社会网络结构如何影响集体决策的平等性、速度和准确性？该研究计划利用了巴拿马大anis的长期（10年）数据集，这些大anis生活在一个由多个不相关的繁殖对组成的群体中。有些团体非常稳定，由相同的成员组成超过十年；而另一些则由经验丰富的个人和新人组成。阿尼斯与其他非配偶的群体成员表现出密切的从属关系，先前的研究发现，这些关系的持续时间会影响协调行为。在这个项目中，群体成员之间的偏好冲突将通过操纵巢址质量和不同个体可获得的信息而产生。这将使假设检验成为可能：当群体成员的意见发生冲突时，他们是如何达成集体决策的；个体是如何沟通偏好的；以及消息灵通的个体的存在是否会改变集体决策的结果。对个体生活史和群体稳定性的自然变化的了解，结合群体成员之间互动的RFID跟踪数据，将揭示社会网络结构如何影响集体决策的过程和结果。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Solving collective problems is one of the central challenges of group living. When individuals prefer different outcomes, how do societies agree on one choice for everyone? Human groups have developed a variety of methods, from despotism to democratic voting. Collective decision-making in animal groups is less well understood, although examples are ubiquitous: a honeybee colony picks a new location for the hive; a monkey troop invades a neighboring territory; a flock of birds changes its roost site. Theoretical models have been developed to predict the conditions under which such decisions should be shared, and how the structure and stability of the social group might influence the speed and accuracy of these decisions. However, experimental studies on wild animals are rare, leaving gaps between theoretical predictions and empirical evidence. This project explores these gaps in a tropical bird, the greater ani. Anis nest in social groups composed of several pairs, which build a single nest in which all of the females lay their eggs. The choice of where to build the nest is a crucial decision, since its location determines its exposure to predators. The project combines field experiments, behavioral observations, and tracking techniques to test how groups arrive at shared decisions - and, crucially, which opinions prevail when group members disagree. This project will provide research experiences to students and a postdoctoral researcher, training to Panamanian researchers through a series of public workshops, and outreach to the public through a partnership with the Smithsonian Tropical Research Institute. This project explores three major questions about collective decision-making that have arisen from recent theoretical work. First, do shared decisions become less democratic as delays in decision-making grow more costly? Second, can a well-informed minority exert disproportionate influence over group decisions? Third, how does social network structure affect the equality, speed, and accuracy of collective decisions? The research plan leverages a long-term (10-year) data set on greater anis in Panama, which live in groups containing multiple unrelated breeding pairs. Some groups are remarkably stable, consisting of the same members for over a decade; whereas others consist of a mix of experienced individuals and newcomers. Anis show close affiliative relationships with other group members who are not their mates, and prior research has found that the duration of these relationships affects coordinated behaviors. In this project, conflicts of preference between group members will be created by manipulating nest-site quality and the information available to different individuals. This will enable hypothesis testing of how group members arrive at collective decisions when their opinions conflict, how individuals communicate preferences, and whether the presence of well-informed individuals changes the outcome of collective decisions. Knowledge of individual life histories and natural variation in group stability, combined with RFID tracking data on interactions between group members, will reveal how social network structure affects the process and outcome of collective decision-making.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.