The ants and the pheromones


TLDR; this is the last edition of The Morning Paper for now. Plus: one strand of research you won’t want to miss!

I was listening to a BBC Radio 4 podcast recently (More or Less: Behind the Stats – Ants and Algorithms) in which the host Tim Harford is interviewing David Sumpter about his recent book, ‘The ten equations that rule the world.’ One of those equations, the ‘reward equation’ models how ants communicate using pheromones, and our own brains keep track of rewards using dopamine.

About 4 and a half minutes into the podcast Tim asks a fascinating question: the reward equation includes a decay or ‘forgetting’ parameter, so what happens if you disrupt established solutions for long enough that their hold is broken? For example, the complete disruption to our established routines that Covid has caused over the last year? The answer for ants, if you disrupt all of the pheromone trails around their nest, is that they converge on a new solution in the environment, but it won’t necessarily look the same as the one they had before the disruption. (If you’re interested in the amazing problem-solving skills of ants and how we can learn from them in computer science, I covered ‘Ant algorithms for discrete optimization’ in a previous edition of The Morning Paper). It’s highly likely that the same thing will happen to us when we can eventually return to normal – the patterns that we establish won’t necessarily be the same as the ones we had before the series of lockdowns began.

The lockdowns (as I write this, we’re in another strict lockdown in England, with no end date given) have certainly disrupted my own routines. I’ve lost the time and space that I depended on for studying and writing The Morning Paper – the one-hour each way train journey on my morning commute, and more crucially with two older children both full-time studying from home, the time and space within the home for the many hours of concentrated work required. I don’t think my love of learning will ever leave me though, and at the same time I’ve been branching out and studying other things: philosophy, ethics, physics, a little maths, a little biology,… I’m really enjoying that. My love of computer science remains of course, but when we finally get to lay down our new pheromone trails and establish a new normal, I’m not sure I’m going to want to focus on computer science to the exclusion of all else. It’s been an intense six-and-a-half years doing largely that while writing the blog. For the time being then, I’m putting The Morning Paper back on pause.

Before I wrap up though, I can’t resist pointing you in the direction of one incredibly exciting research project from the Hydro team at Berkeley’s RISELab. Joe Hellerstein recently posted a whole bunch of links and resources in this Twitter thread: