How groups of animals make decisions

Elizabeth Preston, Sneezing Dogs, Dancing Bees: How Animals Vote, NYTimes, March 2, 2020:

Any animal living in a group needs to make decisions as a group, too. Even when they don’t agree with their companions, animals rely on one another for protection or help finding food. So they have to find ways to reach consensus about what the group should do next, or where it should live. While they may not conduct continent-spanning electoral contests like this coming Super Tuesday, species ranging from primates all the way to insects have methods for finding agreement that are surprisingly democratic.

Preston discusses meerkats, honeybees, African wild dogs, rock ants, and baboons:

Primates, our closest relatives, have provided lots of material for researchers studying how groups make decisions. Scientists have seen gibbons following female leaders, mountain gorillas grunting when they’re ready to move and capuchins trilling to each other.

Sometimes the process is more subtle. A group may move across the landscape as a unit without any obvious signals from individuals about where they’d like to go next. To figure out how wild olive baboons manage this, the authors of a 2015 paper put GPS collars on 25 members of one troop in Kenya. They monitored the monkeys’ every step for two weeks. Then they studied the movements of each individual baboon in numerous combinations to see who was pulling the group in new directions.

The data showed that any baboon might start moving away from the others as if to draw them on a new course — male or female, dominant or subordinate. When multiple baboons moved in the same direction, others were even more likely to come along. When there was disagreement, with trailblazing baboons moving in totally different directions, others would eventually follow the majority. But if two would-be leaders were tugging in directions less than 90 degrees apart, followers would compromise on a middle path. No matter what, the whole group ended up together.

Ariana Strandburg-Peshkin, an animal-behavior researcher at the University of Konstanz in Germany who led the baboon study, points out that unlike in humans, no one authority tallies up baboon votes and announces the result. The outcome emerges naturally. But the same kind of subtle consensus-building can be part of our voting process, too.

“For instance, we might influence one another’s decisions on who to vote for in the lead-up to an election, before any ballots are cast,” she said.