Affordance and Design


Spending 2 years using the train door on the left, it became an unconscious routine procedure for me to get off at the intended stop. It never failed. Then on my first day visiting a new client, I travelled on a different line by the train in the middle. Guess what happened – I failed to open the door and embarrassingly missed my stop! Thanks to having read Don Norman’s book ‘The Design of Everyday Things’ I do not blame myself as being the only idiot here. Now this week, on yet another rail line, I came across the door control design on the right.

Finally, a designer who has got it right. The green light tells me when the door is ready to be opened. I cannot recall ever having used a door ‘close’ button and guess it is a leftover from the days when the slam door closure required a manual action. On the new train a sensor at floor level detects 10 seconds of inactivity, and then automatically closes the door. Bravo. It has only been 25 years in the making.

Affordance and Design
Don Norman’s ‘The Design of Everyday Things’

Perceptual psychologist James J. Gibson is said to first use the term ‘affordances’ in the 1970’s, to describe the actionable properties between an object and a user. More broadly, it forms a relation between a socio-materialistic environment and a lifeform. Humans can only assess objects according to their perceptible properties. In his fantastic book ‘The Design of Everyday Things’ (1988, revised 2013), design usability guru Don Norman adopted ‘affordances’ to further mean a user’s determination of what to do with things. He sensibly says that designed objects must have “affordances to conform to users’ needs based on physical and perceptual capabilities, goals and past experiences”. In his book he identifies that good design will clearly indicate use and avoid inadvertent misuse.

Industry and design standards are often a means to define a set way, to help reduce variability and confusion errors. The similarity between train door control buttons gives appearance of the existence of a design standard. Regrettably, such train door button standard does clearly omit to specify or guide designers in how the buttons should be arranged relative to each other. That is unfortunately a common problem with industry standards.

Affordance and Design
Placement of ‘power’ and ‘delete’ keys on different laptop PCs

Another experience of poor affordances by design happened when I recently started to use a new laptop computer. The ‘power’ button on the new machine is in the relative same place as the ‘delete’ key on my previous machine. This has resulted in several annoying episodes of unintentionally putting the machine into sleep, and having to wait for a restart, when intending to delete a single character. It will take some time to fully retrain my procedural brain, during which time I will likely continue to repeat the mistake. Considering that the QWERTY layout has become a standard, why can the rest of the keyboard layout not also become standard? Again, the answer lays in a problem with industry standards.

It would have saved me – and many thousands of other users – some real hassle if the designers of train door buttons and computer keyboard layouts had spend more time walking the Gemba in the users’ world. They just might have foreseen and prevented the use errors that I have made, and will continue to make.

This post illustrates just 2 examples of poor affordance by design. Now try extrapolating this to the many thousands of new products that are developed every year. Our world could be so much more hassle-free and productive, if just all designers would take Don Norman’s book to heart. Applying affordance to medical equipment could also help prevent thousands of errors that result in injuries and loss of life.