Nature: Of Ants and Neurons

Whoever designed the human brain may have used ant colonies as the model. Both are what scientists term ‘complex systems’ that operate and perform hugely complicated task without central control. The parallels between ants and the human brain extends to the Internet, which can be viewed as an all-encompassing digital brain. I’ll come back to the brain in a while. First, let’s zoom in on ants.

If you think about how an ant colony actually functions, it’s simply mind-boggling. Most people assume that there is some central command; ants are obeying instructions from a queen or a set of “leader” ants that would relay instructions. But this is not the case. The queen’s only responsibility is to lay eggs. There is no leader, no true queen that guides them. All the ants ever do is follow a very simple set of rules – receive signal A and do this, sense signal B and do that. Every ant is a blind cog in the machine called the colony; each is unaware of its very participation in a grand scheme.

Yet somehow, when enough ants act together with simple rules of interactions, they are able to create vast underground networks, intricately connected tunnels with storage rooms and nurseries, in thermally regulated architectures that can put human engineers to shame. 

The collective behavior of ants boils down to the three “C’s: cooperation, communication and chemicals. Edward O Wilson, a sociobiologist at Harvard University and the world’s leading authority on social insects, has studied ants for more than 50 years. His book, The Leafcutter Ants (with Bert Holldobler) focuses on one member of the ant family that cooperates so well, that they describe them as a ‘superorganism’, a colony of individuals self-organized by division of labor and united by a closed system of communication [1].

Deborah Gordon, a biologist at Stanford University studies the chemical signals that ant uses to produce complex patterns and how this is mirrored in other systems without central control. She argues that the primary way ants interact is via smell. They smell with their antennae, and they interact with their antennae, so when one ant touches another with its antennae, it can tell, for example, if the other ant is a nestmate and what task that other ant has been doing.”

Chemicals called pheromones are the key to ant communication. Ants have a chemical “vocabulary” of 10 to 20 phrases, enabling them to express attraction, to recruit, convey alarm, forage for food, identify other castes and discriminate between nestmates and strangers. Using pheromones, ants coordinate the third “C” – cooperation. This is perhaps the most impressive aspect of the collective behavior of ants. When the number of ants that have made a particular decision (e.g., ‘turn left on the foraging trail’) reaches a tipping point, the entire colony commits to that decision in a spectacular display of mass cooperation. Nigel Franks, a zoologist from the University of Bristol adds: “They have thresholds for doing things – one for leaving the old nest if it’s not particularly good, one for accepting a new nest if they encounter it and begin tandem running. They then have a threshold for switching from tandem running to carrying if they encounter a quorum in the new nest.”

Professor Deborah Gordon on the Stanford University campus.

From Ants to the Brain

Professor Gordon believes the brain works the same way as ant colonies. Just as an ant add up stimuli from other ants to decide whether to do a specific task, a neuron or nerve cell adds up stimuli from other neurons to decide whether to fire signals. In both cases, chemicals are involved (pheromones for ants, neurotransmitters for the brain). And in both cases, action is triggered only when a tipping point for stimuli is reached. [2]

Although this analogy is useful, it is incomplete, for we have much more to learn about the genius of ants. Ants have been around for 150 million years, far longer than human history. They wouldn’t have been around for so long if they didn’t master the art of turning the simple into the complex, perhaps far better than we can, Gordon quips.

TED Talk: Deborah Gordon on ‘The Genius of Ant Colonies’

Deborah Gordon explains how the colonies organize their work using simple olfactory interactions and how that collective behavior has evolved to solve diverse ecological problems. Such insights could help scientists better understand other systems that operate without central control, such as the brain and the internet.

Further Study

[1] Bert Holldobler and Edward O. Wilson, The Leafcutter Ants, Harvard University Press, 2010.

[2] A team of six computer scientists led by James Marshall (University of Bristol)recently used computer models to show that groups of neurons in the primate brain seem to make decisions in roughly the same way as an ant colony. The results, published recently in the Journal of the Royal Society Interface, drew the first formal parallels between decision-making brain circuits in the primate brain and colonies of social insects. Here is the link to their paper:

[3] A Scientific American article on the algorithms of ant colonies (

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