The thing that drove me was this question, right: how does the brain work? And sort of the engineering part of me at some point just took over and said, you know, well, it’s a whole bunch of little devices, and we actually know a fair amount about how each of those individual devices work.

SPAUN is a model, so it’s a piece of software. And what we’re trying to do is simulate how the brain functions. So just like you might simulate a circuit, a digital circuit or something, we want to make sure that each of the devices—which, in the case of the brain, is a neuron—is simulated properly. So we write some equations down that describe how it functions, and then we put hundreds or thousands or millions of them together and make them communicate in a way that is appropriate to reflecting the kind of structures that you find in the brain and to performing some specific function, which we know that the brain performs.

On the medical side, it gives us an understanding of how biology actually results in cognition. Right? So what is—what is it that neurons are doing together to give rise to people being able to remember lists of items, for example. And so we can think about what kinds of interruptions at the biological level—so what kinds of diseases—might change some of the behaviours that we observe.

In recent work, we have taken out some of the very simple cells and replaced them with much more sophisticated cells, where the neurons actually have spatial structures. And what this lets us do is new kinds of experiments with models like SPAUN. So for instance, we can essentially virtually introduce a drug. And because SPAUN has very high-level psychological functions, even though we’re introducing them at the biological level, we can look at the effects at the behavioural level.

We can’t do this now, but at some point we may be able to scan your brain or do some behavioural tests, and that will let us build a model which is specific to you. And then we can actually tailor the kinds of neurological interventions to the things that we know about your own brain.

On the more technological side, when we’re building models like SPAUN, we’re actually sometimes getting functions out which are not very natural for computers to do. If we extract those functions and put them into machines, then we have to start worrying about, you know, how we’re going to interact with those machines, what kinds of machines we do want to build and we don’t want to build, and other sorts of sociological questions about what happens if those machines start taking over a lot of the jobs that we typically expect people to do.

All of the simulation tools that we’ve built, all the models that we’ve built, all of the designs for robots and so on are things that we just release to the public. And the reason is that what we’d really like to do is to have not only our lab but many labs around the world adopt these kinds of methods so we can build something like a grand, unified model across many labs across many countries. Because I ultimately think that’s the only way we’re going to be able to tackle the kind of complexity that we observe in the biological brain.