…He spoke with Knowable Magazine…. “One of the experiments we did compared the ability of individual ants or colonies to distinguish light levels. We found that when light differences are tiny, the colonies make better decisions than individual ants do. It’s a nice example of the wisdom of crowds—groups can improve their acuity or precision by combining the efforts of many relatively noisy, imprecise individuals. But where there’s a big difference in brightness, the individuals working on their own actually get the question right more often than the colony does. That surprised us, because we were expecting the wisdom of crowds to work across the board.Our best guess is that there is a downside to the way these colonies integrate information. One animal finds a dark nest, and she’ll recruit a nestmate with a probability that depends on how dark the nest is. Another ant will find a competing nest that’s maybe a little bit brighter, so she’ll recruit a nestmate to that with a probability that’s a little bit lower, because the nest is not quite as good. The ant who’s been recruited then decides herself whether she’ll stick with that nest and start recruiting still others to it. That allows the colony to detect a small difference in light level and move to the darker and better nest. But sometimes, just by chance, one ant makes a mistake and recruits others to a nest that’s not very good. If the ants she recruits also make a mistake and get too excited about this not-very-good nest, then pretty soon you can have an amplification of the error—the madness of crowds. That doesn’t happen often, but it’s a danger that’s always present. For an individual ant, that can’t happen, because she has to do everything on her own. If it’s obvious which nest is brighter, then an individual ant can solve it on her own with a high probability of being right. And since she doesn’t have this danger of falling into a positive feedback cascade, then maybe she can do better in those cases than a colony can…
Giancarlo Angulo's Blog