So Bob's your interface :Opinion

Have you ever wondered why such a high proportion of the population seems to find it hard to set a video recorder? It is tempting to dismiss those who are baffled by the VCR as technological incompetents, especially since many are middle-aged people who have to rely on their more computer-aware children.

The truth is, the VCR problem is the fault of the machines' designers, not their users. Why this should be holds some interesting lessons for the computer industry.

What makes a VCR different from a car - a more complex machine that demands greater skill of its user - is that its controls have no mechanical link with their functions. The steering wheel looks as though it is meant to be turned; the handbrake as though it is meant to be pulled. And both of these controls give the user instant feedback. Turn the steering wheel, and you feel the friction of the tyres scraping against the tarmac; pull up the handbrake, and you hear the noise of the ratchet that holds the brake in position.

Until recently, video recorders provided no such feedback. To record a single television programme, users have had to carry out as many as 30 steps - pressing small buttons to indicate the starting time and date, the ending time and date, and the channel. Yet not until the very end of the process was there any clue as to whether it had been done correctly.

To make matters worse, the buttons were all the same size and colour. This difference highlights a broad class of faults in the design of electronic goods - faults that grow with the complexity of the machine and the number of steps to be followed in sequence when using it.

Yet the problem is not insuperable. Even with an electronic device whose buttons are straight electrical switches, the links between control can be recreated. Take the fax machine: someone who knows how to use one machine can usually use another - all because makers of the machines have arrived at a de facto standard by making the start button green. On the vast majority of machines, sending a fax consists of inserting the paper, dialling the number and pressing the green button.

Since computers and their programs are more complex than other machines, finding such links between control and function is more important for writers of computer software than for anyone else. Yet they have only recently begun to grapple with the problem. Between 1960 and 1980, while huge strides were made in memory and processing power, computers did not become noticeably easier to work with. When you decided to scrap a letter half-way through, an IBM PC required you to type something like "del c:\wp\docs\letter.txt"

- and then "Y" to confirm that deleting the letter was what you really intended.

Only the arrival of the Apple Macintosh (itself indebted to an earlier Xerox machine) changed matters. On a Mac, you simply clicked on the document's name with the mouse, dragged it across the screen to a small dustbin, and dropped it in. At a stroke, this thinking revolutionised the computer. It took the computer forward by taking it back to the mechanical age.

Now that many features of the Macintosh graphical interface are also to be found on computers that run Microsoft's Windows, the idea of issuing commands by clicking with a mouse on "icons" on the screen is taken for granted. But every new spreadsheet andword processor brings with it new functions, and hence new levels of complexity. Software companies are acutely conscious that the new functions will not be useful unless their customers can master them with reasonable speed; so they have begun to standardise their products.

Just as drivers expect to find a new car's gearstick and handbrake in the same place as in their current model, so, too, are programs easier to learn if they look like something the user is already accustomed to. This is why someone trying to print a file in Lotus's SmartSuite will find that the "print" icon looks the same and is in the same place in the spreadsheet, the database and the word processor.

This month, however, both Microsoft and Apple have unveiled new approaches to making software easier to use. Instead of trying to make their programs behave like machines, they are trying to make them behave like people. Separately, the two firms are developing new kinds of anthropomorphic "interfaces": their programs will answer to names like Bob, and will display more human warmth and fewer incomprehensible error messages.

At first sight, this seems a mistake. Novices may value friendly software; more experienced users dislike it. If the computer will do what they want, it should shut up and get on with it; if not, it should say concisely why it cannot. Many customers willtherefore be hard to convince that the new approach is of value.

But Apple and Microsoft may be on to something. As software becomes more complex, it is increasingly doing jobs that we think of as anything but mechanical. The latest word processors have features that Microsoft, with justification, calls "wizards": they will not only check your spelling and grammar, but also offer draft texts when you have to write a letter of condolence or offer someone a job. Many people will feel guilty delegating such tasks to a computer. Perhaps it helps to ease the pangs if thecomputer behaves more like a person than a machine.