We continue to explore our question, this week focusing on affordances.  

‘Refer to the actionable properties between the world and an actor (a person or animal) … affordances are relationships. They exist naturally: they do not have to be visible, known or desirable’ J. J. Gibson’s (1977)

I found Gibson’s explanation of affordances a bit complicated as it is very abstract, and I did not consider a person having a relationship with an object. I knew that people used objects and tools, but I didn’t give much thought to the influence of an object into a person.  

Trying to understand more in-depth the concept, I found in the day to day examples of design given by Donald Norman in his book, The Design of Everyday Things (2002) examples easier to comprehend. Norman’s approach to design is a combination of engineering and psychology studies, centering on the users’ experience.  

‘Affordances provide strong clues to the operation of things. Plates are for pushing. Knobs are for turning. Slots are for inserting things into. Balls are for throwing or bouncing. When affordances are taken advantages of, the user knows what to do just by looking: no picture, label or instruction is required… When simple things need pictures, labels or instructions the design has failed.’ (Norman, 1999)

Norman continues this further, explaining a perceived affordance, which is determined by what the user perceives the action to be, rather than every possibility that could be true (1999). 

Because perceived affordances rely on the user’s perceptions, designers will need to think about constraints, including physical, semantic, cultural and logical.

–      Physical constraints are the limited actions or uses of a device determined by the physical properties itself.  

–      Semantic constraints rely on the user’s knowledge of the situation and their understanding of the world.  

–      Cultural constraints are based on acceptable cultural standards, which may not affect the physical or semantic use.  

–      Logical constraints use reasoning to determine the options and can guide the user in operating. (Norman, 1999).  

For a successful design, affordances and constraints need to be combined with mapping an object to create a conceptual model.  Therefore, a successful design cannot just rely on affordances, as there will be other constraints that will influence the user’s interaction. Norman sees this conceptual model as the most important aspect of design and also a difficult element for designers (1999).  

 

References:

Norman, D 1999, ‘Affordance, conventions and design (Part 2)’, Nielsen Norman Group, viewed 1 April 2012, <http://www.jnd.org/dn.mss/affordance_conv.html>

Norman, D. (2002). The design of everyday things (1st Basic paperback ed.). New York: Basic Books.