machinespace

machinespace = the networked information space of ever-increasing complexity that humans have to interact with.

August 12, 2004

affordance and usability

here we go again...

I was thinking about 'affordance' and 'usability', and was wondering whether there are really barriers to designers creating affordable interfaces.


I rooted around, and dug up a few definitions to make sure my understanding of the term affordance was the same as everyone else - and voila, I have one from the sage himself...

from www.rha.com/ui_design_glossary.htm


Don Norman sayeth "the perceived and actual properties of the thing, primarily those fundamental properties that determine just how the thing could possibly be used."

Alan Cooper refined this definition by omitting "and actual", identifying perception as the crux of the problem.

"The whole point is that, through a combination of instinct and experience, we expect objects to behave in a certain way based on their appearance and we have very strong expectations if we've used an identical object before. If a designer violates one of these expectations, their user will suffer frustration every time they use the interface."

other definitions of affordance on the Web:

from www.parc.com/istl/groups/hdi/sensemaking/glossary.html
"An affordance refers to a physical property of something that influences how it can be used. For example, the affordances of paper include its properties for being viewed, it's light weight, and so on. The nature of a handle on a door determine how one open the door - by pulling, or pushing, or twisting, and so on."

and from http://www.slostc.org/topics/usability/definitions.html

"Perceptual characteristics of an object that make it obvious what the object can do and how it can be manipulated."

and yet one more...
from http://ei.cs.vt.edu/~cs5714/glossary.html

"an aspect of an object which makes it obvious how the object is to be used."

1. Which brings up some interesting questions - why put the perception burden on the UI alone?

2. are there any recent studies on the affordance of currently favored widgets? after all, when designing a web based application, we tend to use lots of widgets other than the standard buttons - dropdowns, multi-column list boxes, treeviews, list boxes etc etc.

3. Can working (ie, application grade) widgets be "walk up and use" - ie, provide complete affordance without having any instructions other than the widget interface itself.

4. So, if an interface is affordable - ie, a user can determine instinctively how the controls on the interface can be manipulated, the UI is "affordable" - but is it usable yet?

5. Does affordability of an UI provide the user with enough information to carry out a task, if they have never done it before?

In Alan's definition, perception is the key - if the user perceives the logic behind the layout of the UI, and is provided with the requisite information regarding the sequence of operations to be performed on the UI, then they should be fairly confident of being able to complete their tasks without further training or instruction - of course, a bit of online help never hurts, but can be limited to FAQs, not necessarily a demo training.

Which begs another question -

6. if applications are designed to provide user affordance, why would Organizations need to train people over and and over when they build or modify applications?

Training would be needed only to familiarize users with any process/workflow changes, not on the application UI. If a user has a good sense of how the application should work, and the User interface provides affordance based on that expectation, then they should not have any problems using the application.

Ergo, there you have it - The UI should not have to bear the burden alone. Not if the organization wishes to have a productive usable tool, productivity applications need not have a "wow" factor - it's okay to set up expectations early on, to reinforce affordance, and then build to that.

if affordance is determined by perception, does it not make sense to influence perception in whatever way we can?

Granted, we cannot do this for an application that will be used in the "public" domain - ie the wide wide world of the internet - but within the closed confines of a corporate intranet, with its captive users, it is definitely possible. I'm not ruling out the possibility of applying this method on a public web app, it could work.

corporate users of complex applications over an intranet chould have some "early" instruction (all it training or whatever) in the product design cycle to familiarize them with the new or modified application workflow before the application is ever developed.

I don't mean formal training, just an opportunity to understand and develop a fairly robust mental model of the process... could be as simple as a relationship diagram.

so.. first we design the new/modified application workflow, fine tune through discussion with the client and representative users, then broadcast the workflow/process to everyone.

the design, prototyping and evaluation, development progresses as usual, but the difference is that we have set up "new" expectations, and since we will be building to those expectations, the UI will make more sense, and require less effort to learn to use, since we will be meeting the expectations of the users...

all we will be doing is reinforcing what they already know what to do - just providing the users with the tools to do carry out the process they have been familiarized with.

nothing new here. it's been around for a long time, folks.

it's called collaborative design.

_____________________________________________________
copyright 2004 ajoy muralidhar. all names or brands referenced are the copyright of their respective owners.

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