Wednesday, November 7, 2012

Political Animals

Now that we are finally on the other side of one of the longest, most expensive political campaign seasons of United States history, we find ourselves with a new mixed-bag of leaders. Our nation’s decision-makers include career politicians and new freshman politicians; they include lawyers, military members, doctors, businessmen, farmers, ministers, educators, scientists, pilots, and entertainers; they include Protestants, Catholics, Jews, Quakers, Mormons, Buddhists and Muslims; they include white Americans, African Americans, Asian Americans, and Hispanic and Latino Americans; they include men and women; they include straight and gay people; and oh yeah, they include Republicans and Democrats. With so many differences that generate so many viewpoints, how will they ever find common ground to make the kind of decisions that will move our nation in a positive direction?

Hey, Look guys! We make a peace sign! Image from Wikimedia.
Research into group decision-making in social animals has shown that ants, fish, birds, and bees have all discovered strategies to make intelligent group decisions. If they can do it, we can do it, right? What can we learn from these critters about harnessing the knowledge in all of us to move our whole group in the best possible direction? We will explore these insights in this post, which is a mash-up of two previous posts. To see the originals, check out Can a Horde of Idiots Be a Genius? and Why This Horde of Idiots Is No Genius.

Jean-Louis Deneubourg, a professor at the Free University of Brussels, and his colleagues tested the abilities of Argentine ants (a common dark-brown ant species) to collectively solve foraging problems. In one of these studies, the ants were provided with a bridge that connected the nest to a food source. This bridge split and fused in two places (like eyeglass frames), but at each split one branch was shorter than the other, resulting in a single shortest-path and multiple longer paths. After a few minutes, explorers crossed the bridge (by a meandering path) and discovered the food. This recruited foragers, each of which chose randomly between the short and the long branch at each split. Then suddenly, the foragers all started to prefer the shortest route. How did they do that?

This figure from the Goss et al 1989 paper in Naturwissemschaften shows (a) the design of a single module, (b) ants scattered on the bridge after 4 minutes (I promise they’re there), and (c) ants mostly on the shortest path after 8 minutes
You can think of it this way: a single individual often tries to make decisions based on the uncertain information available to it. But if you have a group of individuals, they will likely each have information that differs somewhat from the information of others in the group. If they each make a decision based on their own information alone, they will likely result in a number of poor decisions and a few good ones. But if they can each base their decisions on the accumulation of all of the information of the group, they stand a much better chance of making a good decision. The more information accumulated, the more likely they are to make the best possible decision.

In the case of the Argentine ant, the accumulated information takes the form of pheromone trails. Argentine ants lay pheromone trails both when leaving the nest and when returning to the nest. Ants that are lucky enough to take a shorter foraging route return to the nest sooner, increasing the pheromone concentration of the route each way. In this way, shorter routes develop more concentrated pheromone trails faster, which attract more ants, which further increase pheromone concentration of the shortest routes. In this way, an ant colony can make an intelligent decision (take the shortest foraging route) without any individual doing anything more intelligent than following a simple rule (follow the strongest pheromone signal).

Home is where the heart is. Photo of a bee swarm by Tom Seeley
Honeybee colonies also solve complicated tasks with the use of communication. Tom Seeley at Cornell University and his colleagues have investigated the honeybee group decision-making process of finding a new home. When a colony outgrows their hive, hundreds of scouts will go in search of a suitable new home, preferably one that is high off the ground with a south-facing entrance and room to grow. During this time, the house-hunters will coalesce on a nearby branch while they search out and decide among new home options. This process can take anywhere from hours to days during which the colony is vulnerable and exposed. But they can’t be too hasty: choosing a new home that is too small or too exposed could be equally deadly. Although each swarm has a queen, she plays no role in making this life-or-death decision. Rather, this decision is made by a consensus among 300-500 scout bees that results after an intense “dance-debate”.

If a scout finds a good candidate home, she returns to the colony and performs a waggle dance, a dance in which her body position and movements encode the directions to her site and her dancing vigor relates to how awesome she thinks the site is. Some scouts that see her dance may be persuaded to follow her directions and check out the site for themselves, and if impressed, may return to the hive and perform waggle dances too. Or they may follow another scout’s directions to a different site or even strike out on their own. Over time, scouts that are less enthusiastic about their discovered site stop dancing, in part discouraged by dancers for other sites that bump heads with them and beep at them in disagreement. Eventually, the majority of the dancing scouts are all dancing the same vigorous dance. But interestingly, few scouts ever visit more than one site. Better sites simply receive more vigorous “dance-votes” and then attract more scouts to do the same. Like ants in search of a foraging path, the intensity of the collective signal drives the group towards the best decision. Once a quorum is reached, the honeybees leave their branch as a single united swarm and move into their new home, which is almost always the best site. 
Each dot represents where on the body this dancer was head-bumped by a
dancer for a competing site. Each time she's bumped, she's a little less enthusiastic
about her own dance. Figure from Seeley, et al. 2012 paper in Science.
But groups can develop better solutions than individuals even without communication. Gaia Dell’Ariccia at the University of Zurich in Switzerland and her colleagues explored homing pigeon navigation by placing GPS trackers on the backs of pigeons and releasing them from a familiar location either alone or in a group of six. Because they were all trained to fly home from this site, they all found their way home regardless of whether they were alone or in a group. But as a flock, the pigeons left sooner, rested less, flew faster, and took a more direct route than did the same birds when making the trip alone. By averaging the directional tendencies of everyone in the group, they were able to mutually correct the errors of each individual and follow the straightest path.

What can we learn from these examples? Like individual congressmen and senators, in each of these examples each individual has limited and uncertain information, but each individual has information that may be slightly different than their neighbors’. This diversity can be our congress’ greatest asset, if they use it in the same way so many animals naturally do. Tom Seeley summarized these approaches based on his insights from years of watching honeybees:

Tom Seeley’s Five Habits of Highly Effective Hives

1. “Group members share a goal”.
This is easy for honeybees, but not as much for us. All of the honeybees in a swarm share the same goal: Find the best possible home as quickly as possible. People are not always similar in our goals, needs and wants and one person’s goals are sometimes in direct conflict with another person’s goals. The trick here is finding common ground.

2. “Group members search broadly to find possible solutions to the problem”.
Seek out information from as many sources as you can. Be creative. Use your personal experience. And if the group is diverse, there will be a broader range of personal experience to harness. Diversity increases the ability of a group to make the best decisions.

3. “Group members contribute their information freely and honestly”.
This requires a welcoming and supportive environment that withholds judgment of the individuals for the ideas expressed. You don’t have to agree with an idea to respect and listen to the person expressing it.

4. “Group members evaluate the options independently and they vote independently”.
Just as scout bees don’t dance for a site they have not visited and assessed themselves, we should not advocate possible solutions or candidates that we have not ourselves looked into and thought critically about. A group can only be smarter than the individuals in it if the individuals think for themselves.

5. “Group members aggregate their votes fairly”.
Everyone gets a vote and each one counts equally. ‘Nuff said.

We can learn a lot from these honeybees. Even when the stakes are high, we can make good decisions for our group if we are open, honest, inclusive, fair and think independently.

Want to know more? Check these out:

1. Couzin, I. (2009). Collective cognition in animal groups Trends in Cognitive Sciences, 13 (1), 36-43 DOI: 10.1016/j.tics.2008.10.002

2. List, C., Elsholtz, C., & Seeley, T. (2009). Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms Philosophical Transactions of the Royal Society B: Biological Sciences, 364 (1518), 755-762 DOI: 10.1098/rstb.2008.0277

3. Seeley, T., Visscher, P., Schlegel, T., Hogan, P., Franks, N., & Marshall, J. (2011). Stop Signals Provide Cross Inhibition in Collective Decision-Making by Honeybee Swarms Science, 335 (6064), 108-111 DOI: 10.1126/science.1210361

4. Dell'Ariccia, G., Dell'Omo, G., Wolfer, D., & Lipp, H. (2008). Flock flying improves pigeons' homing: GPS track analysis of individual flyers versus small groups Animal Behaviour, 76 (4), 1165-1172 DOI: 10.1016/j.anbehav.2008.05.022

5. Honeybee Democracy by Thomas Seeley

6. The Smart Swarm by Peter Miller

7. The Wisdom of Crowds by James Surowiecki


  1. I dunno, that "peace sign" looks more like Pacman where the GOP and Democrats are eating the Independents.

    1. I guess that's a valid alternative interpretation ;)

  2. I'd really appreciate if you recommend other resources concerning this theme of course in case you know any of them.

    1. What kinds of resources are you looking for? If you want books, the three I listed above (Honeybee Democracy, The Smart Swarm, and The Wisdom of Crowds) are all fantastic. As for papers, there are many and it would depend on your interests: insect foraging, bird navigation, fish schooling, predator/prey interactions...