Principles of Design #51 – Affordance

Sep 20 2013

Affordance is a term used in design to describe how the characteristics of an object or environment influence (and communicate) the way its function, or as Wikipedia defines it, “A quality of an object, or an environment, which allows an individual to perform an action. For example, a knob affords twisting, while a cord affords pulling”.

Affordance arises because some objects and environments are better suited to specific functions and actions than others. For example, round wheels are better suited to rolling than square ones – so they afford rolling. It is possible to roll a square wheel, but its much easier with a round one. ┬áIn James J. Gibson’s original concept of affordance focused on physical possibility, but later work has focused more on perception and the discoverability of possibilities in human-object interactions, as in the work of Donald Norman (read more here). The concept is used in psychology (perceptual, cognitive, environmental) as well as industrial and interaction design and artificial intelligence.

Thus a user’s goals, plans, values, beliefs and past experiences are just as important as physical characteristics in defining how an object or environment can be interacted with (its affordance). Affordance is a relational concept, dependent on the system and not fixed or absolute.

Designs work more efficiently and are easier to use when the affordance of an object or environment match the intended function (ie I type the letter ‘a’ on my keyboard and a letter ‘a’ appears on the screen; I swipe down on the trackboard and I move down the page of text). Conversely, if an affordance conflicts with intended function, designs are less efficient and more difficult to use. For example, a door with a handle affords pulling, while a door with a flat plate affords pushing. If you want someone to push a door, using a flat plate is more efficient than using a handle.

LEGO afford plugging into each other in the way they are designed. The desktop metaphor for computers makes use of images of common objects and environments (eg desk, trash can, folder) to leverage the existing knowledge and mental maps of users, indicating function and making use easy and intuitive.

The concept of affordance is more broadly applicable in designing brand identity. For example, if your customer’s goal is simplicity and honesty, then a white brand design with a childlike logo, simple language and all natural ingredients ‘affords’ the satisfaction of simplicity and honesty (read Brand esSense for more on this).

Always design brands, products, services and environments to afford their intended function and to align with user’s goals (and avoid negatively afford the wrong use). Also, mimic familiar objects and environments and leverage common signs and symbols (eg red is hot) to communicate how a system can and cannot be used. When affordances are built into a system, there is really no other way it can be used.

REFERENCES

Universal Principles of Design by Lidwell, Holden & Butler

The Design of Everyday Things by Donald Norman

One response so far

  1. Christian

    Thanks for your mail and for asking. The image is not mine, but was sourced through google (the blog is non-commercial).

    Neil

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