The tapping task was developed by Mike Albers of ECU for measuring the usability of written items. It involves the principles of cognitive psychology called, cognitive load.

Cognitive load is said to be the amount of information that one can concentrate on before losing focus. When "overloaded" the mind switches to concentrating on only one piece of information and effectively ignores the rest. Thus, it is theoretically impossible to really multi-task, because we can really only concentrate on one thing at a time.

Cognitive load theory is easily proven by people who try to drive while talking on their cell phones. When accidents occur it was probably due to a portion of the conversation when the drive had to devote a large amount of cognitive ability to the phone call, and thereby the driver automatically neglects the second task: driving. A simpler version is patting your head and rubbing your belly at the same time: you can do it if you concentrate, but it's still a little tough to do.

In the usability measuring device that Albers calls the tapping task, a participant is asked to sit in front of a monitor and view a particular web page. The participant is then asked to complete some type of task that forces them to navigate through a web site. While they are undertaking this task they are asked to, at the same time, physically perform some type of rhythmic tapping. This is done either by drumming or tapping the fingers, a pencil, or their foot. An observer then watches for the moments when the tapping slows or stops completely. At those moments, it is thought that the participant has reached a cognitive overload.

Albers found that this occurs when web pages force participants to focus unnecessarily on the text. Instead of intuitively-named links, for example, links are difficult to understand. The information may also be too complex and hard to read. Further, Albers found that in long, scrolling pages the tapping slows and stops, suggesting that readers find it difficult to locate information they are searching for on such a page.

Testing of the tapping task was performed mainly on web pages, but we can assume that such a test would also be possible with any written document. More testing will most certainly be carried out, but for now the tapping task does hold good promise for helping us better understand how to improve the usability of written information.