Spiderwebs, cognition, and AI


“The Thoughts of a Spiderweb” appeared in Quanta Magazine and was reprinted in The Atlantic. It presents research on how spiders adjust their behaviors when something adjusts in their webs, like some of the strands being snipped. In an experiment, the spiders began using the dangling web threads to catch insects and pull them up to the web. One researcher argues that similar to how an octopus has neurons in its tentacles, a spider’s cognition extends beyond its small brain to its web itself.

Overall, I’d give the discussion a 10 on showing various viewpoints and questions. It’s fun to explore new ideas while some skeptics defend the brilliance of spiders and others ask for distinctions between tools and actual cognition. A few notable, delightful quotes:

On how neurons can function outside the brain:

Perhaps the prime example is another eight-legged invertebrate. Octopuses are famously smart, but their central brain is only a small part of their nervous systems. Two-thirds of the roughly 500 million neurons in an octopus are found in its arms. That led Binyamin Hochner of the Hebrew University of Jerusalem to consider whether octopuses use embodied cognition to pass a piece of food held in their arms straight to their mouths.

For the octopus, with thousands of suckers studding symmetric arms, each of which can bend at any point, building a central mental representation of how to move seems like a computational nightmare. But experiments show that the octopus doesn’t do that. “The brain doesn’t have to know how to move this floppy arm,” Cheng said. Rather, the arm knows how to move the arm.


After describing how jumping spiders sometimes vibrate another spider’s web to draw it into a fight:

“How an animal with such a small nervous system can do all this should keep us awake at night,” Cross and Jackson write in an email. “Instead of marveling at this remarkable use of representation, it seems that Japyassú and Laland are looking for an explanation that removes representation from the equation — in other words, it appears they may actually be removing cognition.”


Now onto the philosophical and metaphysical stuff:

Japyassú’s paper defines cognition in terms of acquiring, manipulating and storing information. That’s a set of criteria that a web can easily meet. But to many, that seems like a low bar. “I think we’re fundamentally losing a distinction between information and knowledge,” Wcislo said. Opponents argue that cognition involves not just passing along information, but also interpreting it into some sort of abstract, meaningful representation of the world, which the web — or a tray of Scrabble tiles — can’t quite manage by itself.

My own thoughts here are, what’s the difference between cognition and a USB drive or a script that takes information, analyzes it in a certain way, and provides an output of some form of action? For example, at my job, someone on the HR team runs a script that watches for when an employee has been on the team for a year and sends their name to an HR staff member, so they know to ask if that person wants to mentor a new hire. In Japyassu’s definition, would the combination of the hire date data and the script itself have cognition?

It’s a subtle difference. But experts who subscribe to Dawkins’s extended phenotype idea, like Vollrath at Oxford, believe that webs are more like tools the spider uses. “The web is actually a computer, as it were,” he said. “It processes information and simplifies it.” In this view, webs evolved over time like an extension of the spider’s body and sensory system — not so much its mind. Vollrath’s lab will soon embark on a project to test just how webs help the spiders solve problems from the extended phenotype perspective, he said.

This is a fascinating statement, and I expect the perspective to evolve. It does make sense to compare the spider web to a computer. To have that sentiment discount the ability of the spiderweb to represent extended cognition, though, ignores rapid developments in AI and bionics. You can already play Pong with your brain. Computers already can function at such a sophisticated level of discourse, their actions can be indistinguishable from humans. Do they have their own cognition? What happens when their ability to do so reverses, so not only do we tell the pong paddle to move, but it sends information to us directly?