Even older than Raskin

As promised, a post about Fitts's Law - the second post about GUI paradigms.

Paul Fitts was an Ohio State Univerty psychologist who developed a model about human movement (wikipedia).  It turned out to be a very accurate and usable model, predicting how fast we (humans) can accurately aim at a target depending on the size and the distance of the target. This model is called Fitts's Law.

The reason why Fitts's Law became so widely used in GUI design is because it's well applicable to the usage of pointer devices such as the mouse - it predicts, for example, why it's so easy to hit targets that are on the edge of your screen (and even easier to reach targets that are on the corners of your screen). For details, see the (somewhat dated) article on AskTog: First Principles of Interaction Design. Or, for a straight-forward explanation of the impact of Fitts's Law: see Particletree's Visualizing Fitts's Law.

The reason why I post about it is the reason that we're still discovering new ways about how to apply a well-known law from 1954:
- In 1954, Fitts's law was "discovered"
- In 1984, Fitts's Law is used "for real" for the first time (I think) in a Graphical User Interfaces (GUI) with the Apple Macintosh, having a menu bar always on top of the screen which is very easy to target
- In 2003, Apple introduced Exposé with Active Screen Corners, making effectively use of these easy-to-use areas to operate functions in your computer
- In 2009, Windows 7 was introduced - using the edges for arranging your windows quickly - just smash a window to the top to maximise it, to the left to fill only the half of your screen et cetera.

That means that, 54 years after Fitts developed his model about human movement, we're still finding new ways how to implement it the right way. That's a long time - about 10 generations. And it makes me look forward to what ways we'll find the next 30 years about how to operate touch devices :-)...