WHERE HUMAN ANATOMY meets data processing, there are just two important devices: the brain and the wristwatch. The brain is nice, but it doesn’t tell time very well. So, creatures of habit that we are, we strap on that extra thing—a machine worn every day by most adults in the industrialized world to display a single piece of data.

It’s starting to look as though this may not be a particularly creative use of valuable anatomical real estate. Technology is outpacing fashion. Now you can buy wristwatches that tell time and . . . announce your appointments . . . monitor your pulse and blood pressure . . . store phone numbers . . . check the air or water temperature . . . compute sums . . . play music. There are emergency-beacon watches for pilots and at least a prototype of a matchmaking watch: put your essentials into a data base and the watch of a suitable romantic interest will blink when you draw nigh. Besides locating you in the fourth dimension, some watches can locate you, or at least orient you, in the first three—with altimeters, depth finders and electronic compasses.

Watch technology, of course, lives by the ever-smaller, ever-faster microchip technology. We have specialized computers in dishwashers and greeting cards; we may as well wear them on our wrists. A chip with the processing power of an early Apple P.C. fuels the Data Link, a new five-alarm appointment manager, to-do list and phone book from Timex. Watch technology is also a rocky shoal for pioneers of input-output ergonomics: the drawbacks of a tiny keyboard strapped to one hand are obvious, but they were not obvious enough for some manufacturers, it seems. The Data Link has its own approach to data transfer, using an electric eye: point it at your computer screen and it grabs new appointments or phone numbers bit by bit from an eerie blinking bar.

It’s still easier to draw a new wrist technology in a comic strip than to sell it to consumers.

The major watch companies in the United States and Japan believe that smarter watches are the future, and they may be right. The exact time is a marvelous piece of knowledge to carry around on one’s person, but not so marvelous as when the century was young. It has been cheapened by ready availability. You can still treat a watch as jewelry and spend $10,000 on a fine steel Swiss mechanical chronograph, but the snob appeal is no longer in its precision (as it was a generation ago); any $2 quartz watch will keep better time. For $50 you may feel entitled to more.

Snob appeal comes in many guises—now, perhaps, you want lunar phases, multiple time zones and a date that will adjust itself correctly in leap years. Or perhaps you cannot feel truly complete until you wear a climber’s wrist altimeter that stores 50 sets of daily climb data and shows a line chart of progress toward your target altitude, not to mention your maximum descent rate in “ski mode.” Or perhaps your kind of status symbol is the strapped-on mini-minicomputer that you have cleverly programmed to play the bloody game Doom.

NEVERTHELESS, WRIST TECHNOLOGISTS have suffered more than their share of anguish on the path to the perfect tiny device. The most impressive product announcements during the past several years have all been followed by unannounced setbacks.

Residents of a few Western cities have been testing a Seiko Message Watch, which makes extremely clever use of a sliver of FM radio spectrum to receive telephone pager messages, the closing Dow, basketball scores and the weather. The watch itself has evolved from clunky to wearable, and the test project has changed hands several times. Most recently, the company announced last September that the Message Watch would be available in 20 cities by the end of 1995 and 50 by the end of 1996. It won’t happen—after yet more delays, the company is now hoping for a spring 1996 roll-out covering 11 cities.

Then there was A.T.&T., which announced a prototype of a Dick Tracy-esque phone watch and even got the chairman of the Federal Communications Commission to pose with it for photographs last summer. But the wrist phone won’t be arriving in stores any time soon. If anything, prospects are dimmer than ever, because of the detached approach the F.C.C. took when it auctioned off a new cellular phone spectrum last fall. The existing cellular network uses antennas spaced as much as five miles apart, a design that assumed relatively powerful car phones. Today’s cute pocket phones can use that same network but have a battery life measured in only hours or minutes. A wrist telephone would have much less available broadcast power and would therefore need more tightly spaced base stations—every few blocks in cities. The F.C.C. might have pushed the cellular industry in that direction but, in an antiregulatory mood, chose instead to sell the valuable new frequencies with virtually no restrictions.

Our bodies just weren’t designed with that many convenient niches for add-in devices.

It’s still easier to draw a new wrist technology in a comic strip than to sell it to consumers. More than a few flights of designer fancy have crashed against an unwritten size-and-elegance barrier in the marketplace. “While it’s fine to stuff technology into a product, it’s not fine to just stuff technology into a product,” says Lance Becker, director of the Data Link technologies at Timex. “When you put it on your wrist, it’s a piece of jewelry and it defines who you are. Nobody on the planet wants to be defined by a big, fat, ugly thing.”

Still, is it possible that the new proliferation of wrist devices is an early way station on a longer road? It’s clear why we strap these machines to our wrists: Our bodies just weren’t designed with that many convenient niches for add-in devices, especially those that we may need to hold in front of our eyes, ears and mouth. But there are one or two other promising spots—the bridge of the nose, for example, with help from the ears, has been known to support a pair of lenses. Meanwhile, researchers at the Massachusetts Institute of Technology have developed a display screen sitting directly on a tiny chip—with the full resolution of a high-grade computer monitor, yet the size of a contact lens. Several companies are about to release commercial products with displays not much bigger: Reflection Technology has a pocket-size fax receiver and viewer with a one-square-inch screen.

The possibilities are frightening enough. Clever wristwatches might just be a way of beating around the bush—biding time till we insert these devices directly in our bodies. Once you’ve got the television remote control conveniently strapped to your wrist, will you stop there? You’re already way past pacemakers; you’ve seen the Bionic Woman and Robocop; you can stand pierced navels and nose rings. Maybe you’re not too squeamish for what’s next.