Do ants think? Yes, they do – but they think like computers

Navigation expert Eric Cassell, author of Animal Algorithms: Evolution and the Mysterious Origins of Ingenious Instincts (2021), in the book offers some insight into how ants organize themselves using algorithms, without any central command:

Ants are remarkably consistent in their lifestyles: All about 11,000 species of ants live in groups, large or small. There are no known solitary ants.

They live in groups and have developed a social lifestyle that includes “agriculture, territorial wars, slavery, division of labor, castes, consensus building, cities and a symbolic language”. (p. 85) How is this managed by ants with very small brains (200,000 to 250,000 neurons) and very limited individuality?

In comparison, among mammals, the agouti has about 857 million neurons, the capybara 1.60 billion and the capuchin 3.690 billion. Humans have about 85 billion neurons. It seems that the ant is doing something that does not rely on individual problem-solving skills.

Cassell points out that the complex colony organization of the ants, where one queen or several queens lay all the eggs and the other females do all the work, is almost exclusive the domain of very small-brained life forms. The naked mole rat is the only mammal to follow this pattern. Incidentally, compared to other rodents, the naked mole rat has fewer neurons in smaller brains than expected due to its body size.

Such colonies are sometimes referred to as “superorganisms” because the individual organisms work towards the survival of the colony as a whole. Take these leafcutter ants in Brazil:

So what are some of the ant colony methods?

We’re not exactly sure how the ant “algorithm” works out the division of labor, but one study found that young ants typically tend to the eggs, larvae and pupae, while older ants forage outside the nest. Foraging is a much more dangerous activity than looking after the young, so when the older ants forage, fewer days of ant lives are lost for the colony (pp. 89-90). Some ant species have worker hives with specially shaped heads, which are best suited for specific purposes, such as attacking other ants or blocking a tunnel (pp. 95-96). In that case, they may be naturally drawn to the task without having to think about it. They just find it easier than the differently structured ants.

Ants communicate primarily through pheromones, scents that provide information. In their book, The superorganism: the beauty, elegance and strangeness of insect societies (2008), Bert Hölldobler and EO Wilson (1929-2021) identified twelve areas of communication mediated by pheromones, including “alarm, attraction, recruitment, grooming, feeding, exchange of liquids and solids, group effect, littermate recognition, caste determination , control over other individuals competing for reproduction, territoriality, and sexual communication” (p. 90).

What makes pheromones a complex communication system is that most of the emissions are made up of several mixed pheromones rather than just one. Some signals are recognized by all ants in the vicinity, others only by their own species, and still others are specific to the ant colony.

An evolutionary biologist describes the processing of pheromones as equivalent to AND gates and STOP in a computer system. (p. 91). The ant doesn’t so much decide what to do, but reacts to an AI-like signal.

Computer programmers have adapted ant algorithms to the computer:

Welcome to the Internet!

Stanford’s Deborah M. Gordon, an ant behavior specialist, considers the complex algorithms ants use to communicate without personal understanding as the “antennae”:

Ant colonies use dynamic networks of short interactions to adapt to changing conditions. No ant knows what’s going on. Each ant simply keeps track of its recent experience of meeting other ants, either in one-on-one encounters when ants touch antennae, or when an ant encounters a chemical deposited by another.

Deborah Gordon, “What do ants know that we don’t?” Bee wired

Deborah M. Gordon

She gives an illustration:

One strategy ants use (known from our own data networks) is to set up a circuit of permanent highways – such as a network of cell towers – from which ants search locally. The invasive Argentine ants are experts at this; they will find every crumb that ends up on your counter.

The Argentine ants also adjust their paths, shifting from an almost random walk when there are many ants around, causing each ant to search thoroughly in a small area, to a right-hand path when there are few ants around, making the whole group to cover more ground.

Like a distributed demand-response network, each ant’s aggregated responses to local conditions generate the system-wide outcome, without any centralized direction or control.

Deborah Gordon, “What do ants know that we don’t?” Bee wired

So the individual ant does not know what is going on and there is no master ant in the colony (the queen only lays eggs, she does not rule). That’s where the algorithms come in; the ant uses prepackaged solutions for conventional conditions, such as adjusting the food search based on the number of employees.

For social insects, the superorganism structure has been very successful, Cassell notes. In terms of numbers, there are many more social insects than solitary insects such as cockroaches, grasshoppers and beetles, and no major group of social insects is known to be extinct (p. 92). An ant colony in Hokkaido, Japan, has more than 300 million workers and a million queens in interconnected nests (p. 96).

Cassell tells us that because of the sheer complexity of its lifestyle, its favorite species of ant is the leaf-cutter genus, with its remarkably complex farming activities (p. 97):

In general, by studying ants, we can learn how to instantiate intelligence in a colony (the ‘hive mind’) where all members seem to obey an internal algorithm that directs their behavior. In contrast, as the popular phrase “like herding cats” implies, many mammals function as independent individuals, using their more complex brains to make individual decisions, for better or for worse.

Next one: The leaf cutters: ants that act like farmhands


You may also want to read: How do insects use their tiny brains to think clearly? How do they deal with complex behavior involving only 100,000 to a million neurons? Researchers are discovering that insects have a number of strategies for making the most of relatively few neurons to enable complex behavior.

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