1Percenter

Bruce Tognazzini, Tog for short, is a well-known user-interface expert and was Apple employee #66. He is the author of a 3 part article comparing the speed of completing tasks with the mouse vs. the keyboard: part 1, part 2, and part 3.

To summarize the articles: after testing subjects by having them complete the same tasks with the mouse and with only the keyboard, Tog found that subjects consistently believed they had completed the task faster with the keyboard, when in reality they had completed the task faster with the mouse.

Tog states:

• Test subjects consistently report that keyboarding is faster than mousing.
• The stopwatch consistently proves mousing is faster than keyboarding.

Tog then gives an explanation for the difference between perceived and actual time:

It takes two seconds to decide upon which special-function key to press. Deciding among abstract symbols is a high-level cognitive function. Not only is this decision not boring, the user actually experiences amnesia! Real amnesia! The time-slice spent making the decision simply ceases to exist.

Tog’s articles are a great read, he makes points that contradict people’s instincts and backs them up with cold hard research. But, on the subject of whether the mouse is faster than the keyboard, Tog’s data is inconclusive.

A simple thought experiment will help me explain the reasoning behind that observation: imagine using a software application that is just one window. The window contains a picture of a keyboard and each letter on the keyboard is a button. Click on a button and it types that letter. What do you think would be faster for typing, the keyboard application or a real keyboard?

Most would agree that typing with a real keyboard is faster, which shows that at least the keyboard is faster for something (you may have started to doubt this after reading Tog’s articles). But what’s more important is the reason that it’s faster. The reason that typing with a keyboard is faster is a phenomena absent from Tog’s articles: muscle memory. Typing with a keyboard is faster because we have trained ourselves to the point that the minutiae of typing¹ is instinctual. We don’t think about hitting the individual keys to type a word anymore than we think about moving our hand to flip a light switch. We simply think about the result we want and the rest just happens.

Tog does not address muscle memory in his articles. In fact, his argument seems to be based on the test subjects not having committed the keyboard commands to muscle memory:

Part 1:

It takes two seconds to decide upon which special-function key to press. Deciding among abstract symbols is a high-level cognitive function.

Part 3:

[When using the keyboard], how can someone spending twice as as long at a given task be more productive? They can’t…Under such circumstances, the user must set aside the original task of writing or editing a document in favor of figuring out what key to press and how many times to press it.

In the case of muscle memory, you don’t have to remember anything. The argument that there really isn’t anything to remember when hitting a sequence of keys from muscle memory is supported by reports of people being able to type a password without being able to tell you what they are typing. It follows that there wouldn’t be a “two seconds to decide upon which special-function key to press.”

Tog seems to be making speed comparisons between a the equivalent of a hunt-and-peck typist vs. the mouse, instead of testing a touch typist. This is not surprising. The most straight forward way of performing a speed test would result in just such a comparison: take a random cross section of computer users, tell them which keyboard shortcuts they will be using, and then have them perform a series of tasks using these keyboard shortcuts followed by using the mouse.

This test will get you some great data. It will show you that the mouse is faster in many circumstances. It will help you discover a fascinating phenomena where users “forget” time that they spent “[deciding] upon which special-function key to press.” But it is a far cry from testing a seasoned computer user, who’s been using the same keyboard commands for years, completing real tasks while in flow, on the machine and in the work environment they spend 8 hours a day at.

Please note, that while Tog’s articles are based on actual research, this article is purely speculation. I am not trying to discount Tog’s observations. I am confident that the “high-level cognitive function amnesia” is a real phenomena that results in reduced speed gains when shortcuts not committed to muscle memory are used. This article was written to clarify the articles findings in the pursuit of truth.

Tog is among the most interesting user-interface experts on the web. For those interested in user-interface design, I highly recommend these two Tog articles: A Quiz Designed to Give You Fitts and First Principles of Interaction Design.

1. Moving our fingers to the right keys. ↑