The Emergent Mind

The Emergent Mind: how intelligence arises in people and machines

by Gaurav Suri and Jay McClelland

Such a brilliant book! In The Emergent Mind Gaurav Suri and Jay McClelland present a radical new perspective on how minds work. Most importantly, their version of things does not include any need for a separate self to explain intelligence or behaviour. Instead they describe how networks of tiny neurons can collectively give rise to capabilities far beyond those of any of the individual units involved. They suggest a parallel to how intelligence emerges in colonies of ants.

The emergent mind of ants

Ants are very small creatures who collectively appear to achieve some really impressive things. For example they can build bridges with their own bodies that allow their colony to cross gaps and navigate uneven terrain. But individually they have very small brains that seem to allow them to follow very simple rules such as “if a scent is detected, follow that scent”.

In The Emergent Mind, Suri and McClelland use a simple illustration of ants collectively discovering the shortest route around an obstruction that is placed in between a food source (such as an abandoned half-eaten sandwich) and their nest. Within a few minutes of the obstacle being introduced, most of the ants will be following this new shortest route.

I have experimented with laying out a version of this ant scenario for friends and asking them what they imagine is going on. Almost everybody projected an anthropomorphic ant (maybe inspired by those cartoon characters in the movie Antz) consciously considering their options and communicating their findings to their friends. But this is actually an unnecessary embellishment. The ants leave pheromone trails wherever they go. And they also follow the strongest pheromone trail in front of them. The ants that accidentally find the shortest route will turn around and head home soonest and will therefore be laying the first, and consequentially (as other ants follow them) strongest pheromone trail. So the most sensible route becomes the most popular one. Presumably this is not because any of them ‘knows’ it’s the shortest or most sensible path, but just because ants’ brains are evolutionarily ‘programmed’ to follow pheromone trails.

So how is this relevant to human intelligence?

Human brains involve networks of connections between billions of neurons. They are infinitely more complex than ants’ brains. And yet, like ant colonies (and ants’ somewhat smaller brains) they are made up of lots of individual units that, individually, are nowhere near capable of the immense intelligence that seems to emerge somehow from the interactions between these units. The way that neurons communicate involves them building up electrical charge in response to some sort of stimuli. When this charge reaches a certain threshold it becomes an action potential that ‘fires’ and activates other connected neurons. This in turn increases the other neurons’ electrical charge. Suri and McClelland describe how this seems to work collectively with multiple connections and forward and backward interactions leading to activation or inhibition of other nerve cells. This then appears to give rise to some sort of intelligent-appearing response.

So, for example, that half-eaten sandwich I mentioned earlier, plus the light quality of a certain time of day and a feeling of hunger, tiredness or boredom, may have activated a collection of sensory neurons that have fired off, or inhibited, many other neurons deeper in your brain networks. Other factors such as an aversion to insects or gluten could have also got involved. And somehow, collectively, it may have given rise to a series of actions – perhaps going into the kitchen and making a snack. Or pulling a disgusted face and stopping reading. It sounds incredible and yet something incredible does appear to be happening! And no need for an individual ‘me’ to be involved at all. There is more to be said about the appearance of choice of course – but I will come back to that in a future post….

The emergent mind of frogs

In the meantime, let us consider the mind of frogs. Paul and me once stayed in a rather damp room by a river in Sri Lanka. Throughout our stay there was a continuous line of ants marching down one of the walls. Lower down the wall, at the far end of the ant line, sat a frog with a very flicky tongue. The ants just kept following that pheromone trail and marched straight into the frog’s mouth. They obviously hadn’t yet evolved an instinctive communication system that could protect them from the emergent intelligence of frogs.