The Spike: An Epic Journey Through the Brain in 2.1 Seconds

by Mark Humphries

The second good reason to add deliberate noise to your brain is to help it search better. Many challenges in machine learning are about finding the optimal solution to a problem given some constraints. Like finding the fastest route between two locations—where fastest often does not mean shortest, and the solutions are constrained by speed limits, traffic, your mode of transport, time of day, likelihood of rampaging sheep escaping a field, and innumerable other factors. A machine solving these problems will explore the space of possible solutions. It will propose a solution, evaluate how good it is, and work out how to adjust that solution to find a better one.25 Told you want to go from London to Paris, it will propose one possible route, work out how long it will take, then look at how it can be adjusted—taking a left turn here to get on to a longer road, but one that has a higher speed limit. And repeat this propose-and-adjust cycle until its proposed solution cannot be bettered. The fundamental challenge for searching is that such problems will have many solutions that are adequate, passable, OK, but which are all surrounded by worse solutions, so that any small adjustments from the adequate solution gets worse results. These are little traps in the space of possible solutions. They make these solutions look like they cannot be bettered—but they can, and there may be vastly better solutions out there, somewhere. The many ways of escaping these traps boil down to the sa...