Simple Rules to gather information quickly
Can our complex brains follow simple rules?
Rather than tackling the question “how do organisms make group decisions”, I decided to even more tunnel the challenge down into a more specific one. In any kind of decision-making process (be it consensus, individual, democratic, etc.) a crucial step is information gathering.
More clearly defining the challenge tends to make it easier to find concrete examples in nature. Asking the question “how does nature gather information” I found this interesting article Information flow, opinion polling and collective intelligence in house-hunting social insects, by Franks et al.
This article describes the behaviour of the “scouting” members of groups of honeybees (Apis mellifera) and one species of ant (Leptothorax albipennis) when it comes to hunting for a new nest. The reason why honeybees and ants are good examples is because they are social animals with complex adaptive systems, and have been widely studied with interest to their “swarm intelligence”.
If you are interested in learning more about the specific nest-hunting strategy of honeybees and ants, I would recommend reading the article (section 2&3).
Patterns are a sign of a successful approach
What I would like to discuss here are patterns found amongst these examples. What are similarities in their strategy? Patterns are a sign of a successful approach, since multiple organisms have independently evolved to use the same strategy.
This schematic shows the behaviour process of the scouting bees/ants during the information gathering phase.
Only a very small amount of scouters (~5%) will leave the current nest to find potential new, better nests. Once they found a nest they will assess the quality of it, according to a whole series of variables (e.g. nest size, size and place of entrance, cavity ceiling, etc). Sometimes they might first find other nests and assess them before returning to the current nest. Once returned, they will share their findings on the new nests and will start recruiting followers for their preferred nest. Bees will do their waggle dance, and ants will start a tandem run and lead their follower all the way to the new nest. This recruitment takes a certain time (differs in honeybees from ants), but eventually they will stop their active recruitment behaviour if no followers. Most of the times (except if they are very confident they have found the best new nest) they will follow another scouter to an alternative nest, or they will leave on their own to find other nests and re-asses their options. Only in very small occasions will bees (n/a for ants) completely cease their involvement and will start performing other tasks.
This iterative process is repeated until a certain threshold (i.e. the amount of bees/ants in a new nest, or the concentration of pheromones leading to a new nest) is obtained in order for the entire group to take off to their new home.
It is remarkable how frequently these social insects find the best new nest in a timely fashion. This is not surprising, the costs of not finding a new nest in time can be dramatic: splitting of the group or being exposed to danger.
The behavioural steps that are taken by the scouts are important to be followed by everyone. For example, both honeybees and ants have a time that they pause their active recruitment. Procrastination is the worst enemy of time, but this ensures that a decision is not reached before other options have been considered. A certain amount of intended procrastination makes the system forgiving and self-correcting; however, they all need to follow this rule for it to work correctly. If a scouter doesn’t pause, it is more likely to attract (more) followers than a scouter that does pause, and thus the system will not self-correct for an overly enthusiastic, eager scouter who might not actually have found the best nest.
Procrastination in these social organisms are thus used in an effective way to balance speed and accuracy.
Another important given to the system is that scouters generally are middle-aged and have foraging experience, and are thus most likely to be familiar with the landscape around the swarm. However, at first scouts are neutral/naïve, and thus will not have any preconceived preference between all the possible new nests. The system works because all members clearly have the same goal: they need to find the best possible new nest in the shortest amount of time.
Interestingly, only a very small amount of scouters actually get to visit the different nests that are a close call. The system works even without the need for direct comparison between the best alternative options.
The success of swarm intelligence is the existence and acceptance of simple rules by all members. These simple rules have been developed, tested and optimized over time.
Can we, humans with a much more complex brain, hypothesize simple rules for decision-making processes, test them, and fine tune over time? Or does our emotional capacity limit the acceptance and blind following of such simple rules? Perhaps we can add emotional simple rules and adapt the “simple” system of swarms into more human-adapted systems. An emotional simple rule could be “always be honest” to minimize the influence of personal biases. Yes, this requires practice and openness from everyone. And yes, there will be violators. But just like there are violators that don’t follow the simple rules in swarms, they will be selected out over time, if these violators don’t contribute to the success of the swarm.
It would be nice for me to have simple rules I could follow during my house-hunting process to find a new home. Moving back to Belgium after having lived in the US for almost 4 years is already quite stressful, so finding a house should be made simpler!
If you liked this topic, here are some additional readings
- Franks, N. R., Mallon, E. B., Bray, H. E., Hamilton, M. J., & Mischler, T. C. (2003). Strategies for choosing between alternatives with different attributes: exemplified by house-hunting ants. Animal behaviour, 65(1), 215–223.
- Seeley, T. D., & Visscher, P. K. (2003). Choosing a home: how the scouts in a honey bee swarm perceive the completion of their group decision making. Behavioral Ecology and Sociobiology, 54(5), 511–520.
- Pinter-Wollman, N., Hubler, J., Holley, J. A., Franks, N. R., & Dornhaus, A. (2012). How is activity distributed among and within tasks in Temnothorax ants?. Behavioral Ecology and Sociobiology, 66(10), 1407–1420.
- Pinter-Wollman, N. (2012). Personality in social insects: how does worker personality determine colony personality. Current Zoology, 58(4), 579–587.
- Cronin, A. L., & Stumpe, M. C. (2014). Ants work harder during consensus decision-making in small groups. Journal of The Royal Society Interface, 11(98), 20140641.
And I liked especially this one :)
- Conradt, L. (2008). Group decisions: how (not) to choose a restaurant with friends. Current Biology, 18(24), R1139-R1140.
Evolution/improvement can only work with feedback, so I’m glad to hear from you!