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February 03, 2005

Our ignorance of intelligence

A recent article in the New York Times, which is itself a review of a review article that recently appeared in Nature Neuroscience Reviews by the oddly named Avian Brain Nomenclature Consortium, about the incredible intelligence of certain bird species has prompted me to dump some thoughts about the abstract quality of intelligence, and more importantly, where it comes from. Having also recently finished reading On Intelligence by Jeff Hawkins (yes, that one), I've returned to my once and future fascination with that ephemeral and elusive quality that is "intelligence". We'll return to that shortly, but first let's hear some amazing things, from the NYTimes article, about what smart birds can do.

"Magpies, at an earlier age than any other creature tested, develop an understanding of the fact that when an object disappears behind a curtain, it has not vanished.

At a university campus in Japan, carrion crows line up patiently at the curb waiting for a traffic light to turn red. When cars stop, they hop into the crosswalk, place walnuts from nearby trees onto the road and hop back to the curb. After the light changes and cars run over the nuts, the crows wait until it is safe and hop back out for the food.

Pigeons can memorize up to 725 different visual patterns, and are capable of what looks like deception. Pigeons will pretend to have found a food source, lead other birds to it and then sneak back to the true source.

Parrots, some researchers report, can converse with humans, invent syntax and teach other parrots what they know. Researchers have claimed that Alex, an African gray, can grasp important aspects of number, color concepts, the difference between presence and absence, and physical properties of objects like their shapes and materials. He can sound out letters the same way a child does."

Amazing. What is even more surprising is that the structure of the avian brain is not like the mammalian brain at all. In mammals (and especially so in humans), the so-called lower regions of the brain have been enveloped by a thin sheet of cortical cells called the neo-cortex. This sheet is the base of human intelligence and is incredibly plastic. Further, it's assumed most of the control for many basic functions like breathing and hunger. The neocortex's pre-eminence is what allows people to consciously starve themselves to death. Arguably, it's the seat of free will (which I will blog about on a later date).

So how is it that birds, without a neocortex, can be so intelligent? Apparently, they have evolved an set of neurological clusters that are functionally equivalent to the mammal's neocortex, and this allow them to learn and predict complex phenomena. The equivalence is an important point in support of the belief that intelligence is independent of the substrate on which it is based; here, we mean specifically the types of supporting structures, but this independence is a founding principle of the dream of artificial intelligence (which is itself a bit of a misnomer). If there is more than one way that brains can create intelligent behavior, it is reasonable to wonder if there is more than one kind of substance from which to build those intelligent structures, e.g., transitors and other silicon parts.

It is this idea of independence that lies at the heart of Hawkins' "On Intelligence", in which he discusses his dream of eventually understanding the algorithm that runs on top of the neurological structures in the neocortex. Once we understand that algorithm, he dreams that humans will coexist with and cultivate a new species of intelligent machines that never get cranky, never have to sleep and can take care of mundanities like driving humans around, and crunching through data. Certainly a seductive and utopian future, quite unlike the uninterestingly, technophobic, distopian futures that Hollywood dreams up (at some point, I'll blog about popular culture's obsession with technophobia and its connection with the ancient fear of the unknown).

But can we reasonably expect that the engine of science, which has certainly made some astonishing advances in recent years, will eventually unravel the secret of intelligence? Occasionally, my less scientifically-minded friends have asked me to make my prediction on this topic (see previous reference to the fear-of-the-unknown). My response is, and will continue to be, that "intelligence" is, first of all, a completely ill-defined term as whenever we make machines do something surprisingly clever, critics just change the definition of intelligence. But excepting that slipperiness, I do not think we will realize Hawkins' dream of intelligent machines within my lifetime, and perhaps not within my children's either. What the human brain does is phenomenally complicated, and we are just now beginning to understand its most basic functions, let alone understand how they interact or even how they adapt over time. Combined with the complicated relationship between genetics and brain-structure (another interesting question: how does the genome store the algorithms that allow the brain to learn?), it seems like the quest of understanding human intelligence will keep many scientists employed for many many years. That all being said, I would love to be proved wrong.

Computer: tea; Earl Grey; hot.

Update 3 October 2012: In the news today is a new study at PNAS on precisely this topic, by Dugas-Ford, Rowell, and Ragsdale, "Cell-type homologies and the origins of the neocortex." The authors use a clever molecular marker approach to show that the cells that become the neocortex in mammals form different, but identifiable structures in birds and lizards, with all three neural structures performing similar neurological functions. That is, they found convergent evolution in the functional behavior of different neurological architectures in these three groups of species. What seems so exciting about this discovery is that having multiple solutions to the same basic problem should help us identify the underlying symmetries that form the basis for intelligent behavior.

posted February 3, 2005 02:17 AM in Obsession with birds | permalink