Friday, December 22, 2017

Review: How the Mind Works

How the Mind Works
From How the Mind Works, by Steven Pinker:
Open quote 

The complex structure of the mind is the subject of this book. Its key idea can be captured in a sentence: The mind is a system of organs of computation, designed by natural selection to solve the kinds of problems our ancestors faced in their foraging way of life, in particular, understanding and outmaneuvering objects, animals, plants, and other people."

That's the gist of this 20-year-old best-selling work of popular science. It's what attracted me. After the jump, whether it succeeded.

Grade: C+

In a word, no. In a thousand words, it's passages with dense terminology like this that left me cold.
Many connectionist models offer real surprises about what the simplest steps of mental computation can accomplish. I do think that connectionism has been oversold. Because networks are advertised as soft, parallel, analogical, biological, and continuous, they have acquired a cuddly connotation and a diverse fan club. But neural networks don’t perform miracles, only some logical and statistical operations. The choices of an input representation, of the number of networks, of the wiring diagram chosen for each one, and of the data pathways and control structures that interconnect them explain more about what makes a system smart than do the generic powers of the component connectoplasm.
Source: How the Mind Works.

But let's back up. Although Pinker often gets bogged down in academic language, he does succeed in using his basic hypothesis to explain example after example of human behavior. It's all in the genes: "The ultimate goal that the mind was designed to attain is maximizing the number of copies of the genes that created it."

Why do parents care for their children, even at times sacrificing their own lives? Parents' behavior has been adapted by natural selection to do things that benefit their genes, even after those genes have been passed on to other beings (their children). What about sibling love? Siblings also carry copies of the same genes all siblings inherit from their parents. All of our behaviors are adapted to benefit those genes, not just in our own bodies but in our siblings, and to a lesser extent in our cousins and more distant relatives.

Pinker goes on to show how other human behavior is similarly explained as adaptations by natural selection to maximize the number of copies of one's own genes. "By making us enjoy life, health, sex, friends, and children, the genes buy a lottery ticket for representation in the next generation, with odds that were favorable in the environment in which we evolved."

Pinker's other main argument is the "computation theory of mind." It's trite to say the mind is a computer, but Pinker spends time explaining how the mind is a wholly different kind of computational device than the desktop computer that we're all familiar with. "As many critics have pointed out, computers are serial, doing one thing at a time; brains are parallel, doing millions of things at once. Computers are fast; brains are slow. Computer parts are reliable; brain parts are noisy. Computers have a limited number of connections; brains have trillions. Computers are assembled according to a blueprint; brains must assemble themselves."

Pinker presents vision as a particularly challenging exercise for the computation device that is the mind, which nevertheless solves it better than any computer yet constructed. Understanding the world using only the image presented to the visual field in the back of the eye is, in general, unsolvable. The brain uses context and experience to make intelligent guesses about the image, teasing out individual objects, relative positions and distances from the eye, etc. A well-defined line with different colors on either side might be presumed to indicate the border between two distinct objects. A square with a "bite" taken out of it by a circle is generally presumed to indicate that the square is behind the circle. That this problem is unsolvable in general is demonstrated by illusions designed to fool the eye. Stereo vision evolved to provide significant advantages in solving these puzzles. Put it all together and the brain does an excellent job deciphering the objects out there from just the 2D or 3D image.

Pinker also spends time explaining language, emotions, cooperation, altruism, humor, love, and gender differences. Pinker even has a hypothesis to explain such esoteric behaviors as why some people have a desire to play Russian roulette.

"How the Mind Works" has a lot going for it, but it's a hard slog. Too often it bogs down in academic theory. This book probably is a lot more useful (and interesting) to a student in a college course on cognitive science or evolutionary biology than it is to a general audience. It gets a thumbs-up from me, but just barely.

No comments: