In my previous post, I considered how different forms of embodiment can create different types of intelligences and subjective experiences of the world. This led to a discussion of the dangers of anthropomorphizing every species that shows signs of intelligence into being “just like us.” Now expanding on the varieties of embodied intelligence, we’ll explore if and how intelligent behaviors might be possible in Kingdom Plantae (as some have suggested). This will mostly be about robots, though.
I’ve recorded the sounds that corn and teosinte roots produce. As we listen in on these plants making apparent sonic communication with their environments, it seems important to explore how an organism without a central nervous system might successfully coordinate its various activities (and if it even needs to) and if these behaviors are a sign of intelligence. These particular plants manage to produce subterranean sounds while simultaneously seeking sun for photosynthesis. Both activities play roles in their overall survival. Just how much coordination is needed to do this? Plants lack a central nervous system, making any level of coordination seem unlikely. But is a central nervous system necessary?
The roboticist Rodney Brooks, who I quoted in passing in last week’s post—partially because he mentioned elephants in a paper and partially because I knew I’d be going into more detail on him soon—made great strides in robot intelligence by giving up on consciousness and representation. Rather than build a powerful computer that can contain a map of its world so his robots can navigate that mapped world, Brooks started with the simplest behaviors and added complexity from there. In short, instead of starting with the brain, he made the reflexes first. In his 1987 paper “Intelligence without representation,” he writes that “When we examine very simple level intelligence we find that explicit representations and models of the world get in the way. It turns out to be better to use the world as its own model.”
With a simple sensor and a series of commands, Brooks had robots navigating the real world without a map. The machine would move forward. Sense something. Stop. Turn. Move forward. Sense something. Stop. Turn. It gets even more interesting when Brooks added another layer of activity. But rather than coordinate both layers through a single hub, each layer ran in parallel, “unaware of the existence of the other level.” Brooks and his team retained the layer that could move around and avoid objects, but added a layer that directed motion toward distant visible places. This second layer had no awareness of obstacles, which were handled by the first. With no central coordination, these machines were able to react to real world environments and accomplish tasks with apparent intelligence and ingenuity.
Representation is unnecessary if an organism or robot can sense its environment in real time and react. In “Intelligence without representation,” Brooks notes the earlier work of Herbert Simon, who watched ants navigate a beach and concluded that “the complexity of behavior of a system was not necessarily inherent in the complexity of the creature, but perhaps in the complexity of the environment.” Layers of simple actions acting in parallel can generate systems able to adapt and react to changing situations and accomplish tasks without central coordination or representation. So intelligent plant behaviors could possibly exist without neurons, brains, or representation. I’ll hopefully explore this more in the near future. I am by no means closing the case today.
It’s possible that many of our own behaviors were built up over time through simple systems acting in proximity. This seems especially likely when we consider the work of someone like Lynn Margulis, who I wrote about a few weeks ago. After the discovery of DNA, it was initially believed that all genetic information was kept within cell nuclei. But beyond the nucleus, in the cytoplasm, are organelles with genes of their own. Mitochondria, for instance, produce oxygen in the process of respiration. Their presence is essential to all aerobic activity. Without them, none of us could breathe. Margulis and others eventually established that mitochondria were a separate bacterium that entered cells eons ago, and have stayed ever since. In other words, eukaryotic cells developed through the symbiosis of prokaryotic cells. Mitochondria still possess their own DNA, and replicate independently of the nucleus. They were independent. They remain independent. But they are part of every cell. All our automatic background activities are almost certainly ancient “sub-programs” that we have luckily held onto. We can let them run and just not think about it.
Attempts at artificial intelligence that try to replicate consciousness before making the simple systems that make day-to-day living possible fail in comparison with Brooks’ early work, which puts simple skills together in a single machine and lets them run wild. Brooks has since joined the more conventional world of AI researchers in trying to build thinking humanoids, but his earlier work seems to tell us much more about how bodies and minds function than specialized supercomputers that might do a few things well. (It’s worth noting that Brooks’ robotic vacuum company iRobot, the most successful business in the field, makes machines that operate on the principles of his early work discussed above.)
Addendum/movie recommendation: Rodney Brooks appears in Errol Morris’ 1997 documentary Fast, Cheap & Out of Control, discussing his work, along with an animal tamer, a topiary gardener, and an expert on naked mole rats. The title Fast, Cheap & Out of Control comes (if I’m remembering correctly) from how Brooks described the robots he could make for NASA. Rather than send one $20 million rover to Mars and watch it fail, he could supply them with thousands of robots that would run all over the place and explore in intelligent, unpredictable ways for a fraction of the price. They would be fast, cheap, and out of control. It’s a fun film and full of interesting bits, although you could fast forward the topiary gardening parts and be just fine. Here’s a semi-random set of excerpts someone put together and uploaded to the Internet: