Boffins stalk house-hunting bees, find colony behaves kind of like a human brain
Oh do beehive!
Boffins at Sheffield University have discovered that colonies of honeybees follow the same laws as the human brain when making collective decisions.
For the research, published in Nature Scientific Reports, the team constructed a house-hunting model and treated a simulated bee colony as a single organism, able to respond in a coordinated way to external stimulus, much like a brain.
And how do the bees collectively assess each property?
Scout bees explore the surrounding environment and, having located a potential nest-site, return to the swarm to actively recruit other scouts to that site, through the waggle dance.
When a scout committed to one nest-site encounters a scout dancing for another, it may deliver a stop-signal; a bee that receives several stop-signals reverts to an uncommitted state. The colony makes a decision when the honeybees committed to the same option reach a quorum.
The researchers found that, when treated as whole, the colony obeyed the same types of psychophysical laws as a single animal. Psychophysical laws connect psychological or mental states with physical states. They looked at three: the Hick-Hyman law; Piéron's law; and Weber's law.
As the researchers increased the number of available nests, they witnessed the decision time of the colony increase, as predicted by the Hick-Hyman law.
User interface designers will be familiar with the Hick-Hyman law as an argument for reducing complexity in design, before ignoring it and festooning their sites with a bewildering variety of options.
Researchers then increased the mean nest quality and demonstrated a decrease in the colony's decision time in agreement with Piéron's law (it takes less time to decide between two options when they are of better quality).
Finally, the colony showed an increased error rate in selecting the correct home as the researchers narrowed the difference in quality between nests, agreeing with Weber's law*.
One of the researchers, Giovanni Reina, told The Register: "This is a classic result of psychophysics...not only humans obey Weber's law, but all range of animals from fish to birds, and mammals. Our study suggests that honeybee colonies [also] adhere to the same law when [making] collective decisions."
Armed with this evidence, the team drew a parallel between how the individual bees in the colony, or "superorganism", communicate and how neurons in a brain function. Both follow the same psychophysical laws – a single bee or single neuron may ignore these laws, but the superorganism or brain as a whole follows them.
The importance of this discovery is that psychophysical laws do not only apply to brains, and as such scientists can study processes behind functions including decision-making by staring at a swarm of bees rather than watching brain neurons themselves.
* For those with a love of 19th century German, Gustav Fechner came up with the concept in his book Elemente der Psychophysik.