2 important concepts for better usability

As I mentioned in my last post, I believe (and data I’ve seen at ForeSee Results supports this belief) poor usability is the #1 obstacle to better conversions on our sites.  Getting usability right is hard — very hard. It requires a mindset that is very difficult for most of us to develop naturally. In fact, I’d argue that our natural development tends to pull us further and further away from the mindset we need to design highly usable websites.

Two concepts we need to carefully consider — and strike the right balance between — are “knowledge in the head” and “knowledge in the world.”

Knowledge in the head and knowledge in the world are concepts introduced by noted psychologist, cognitive scientist and author Don Norman is his classic book, The Design of Everyday Things, which I just finished reading. The book was originally written in 1988, well before the web as we know it existed. But the principles he discusses about the design of doors, faucets, phones and other everyday things are extremely relevant to web design. To me, chief among those principles are the concepts of “knowledge in the head” and “knowledge in the world.”

Here’s how Norman explains the two concepts:

Human memory is essentially knowledge in the head, or internal knowledge. If we examine how people use their memories and how they retrieve information, we discover a number of categories. Three are important for us now: 1. Memory for arbitrary things. The items to be retained seem arbitrary, with no meaning and no particular relationship to one other or to things already known 2. Memory for meaningful relationships. The items to be retained form meaningful relationships with themselves or with other things already known. 3. Memory through explanation. The material does not have to be remembered, but rather can be derived from some explanatory mechanism.

Knowledge in the world acts as its own reminder. It can help us recover structures that we otherwise would forget. Knowledge in the head is efficient: no search and interpretation of the environment is required. In order to use knowledge in the head we have to get it there, which might require considerable amounts of learning. Knowledge in the world is easier to learn, but often more difficult to use. And it relies heavily upon the continued physical presence of the information; change the environment and the information is changed. Performance relies upon the physical presence of the task environment.

He goes on to note that “whenever information needed to do a task is readily available in the world, the need for us to learn it diminishes.”

It’s very interesting to look at our sites in the context of these concepts. Imagine a typical customer. What knowledge about how to use the site would she have in her head? How does that compare to the knowledge in our heads about how to use our sites? What’s her educational background, familiarity with web technology and familiarity with our sites versus our educational background, familiarity with web technology and, most of all, familiarity with our own sites?

The reality is, we are not like our customers.

It’s very difficult for those of us who work on sites day in and day out to see our customers’ perspectives. Elitism is the source of poor usability. We all too often consider ourselves to be proxies for our customers. It’s easy to do, and I’ve certainly been guilty of it myself. After all, we are customers of our own businesses, and we see things that work and don’t work for us as customers. We have to remember that we have a lot more knowledge in the head, particularly about our own businesses, than our customers do. And that knowledge in our heads prevents us from seeing our customers’ perspectives. We also easily miss lots of “tree stumps” on our sites that regularly get in our customers’ way.

So, should we just include step-by-step instructions for everything on our sites?

No, I don’t think that’s necessary or even prudent for everything. Norman explains lots of design principles that, if applied, should make many elements of our sites highly intuitive without instructions. But we probably should include a lot more help than we do. We really need to listen to what our customers are telling us and watch them use our sites. It’s the only way to get a better sense of the knowledge in their heads so we can know where we need to include some knowledge in the world.

For example, all too often username or password requirements are not mentioned at the point of entry and customers only find out about them when an error message occurs. Let’s be clear about those requirements upfront.

What type of terminology is being used in navigation? Are customers likely to equate “jackets” with “outerwear” or “stoves” with “cooktops?” One quick way to get a sense of terminology customers use is a review of search terms customers use.

Conventions can be our friends

There are certain conventions that are established enough to effectively be knowledge in the head for most of our customers. For example, navigation on the top of the page and on the left are common enough that we can reasonably expect the majority of our customers to find navigation in those places.If we veer from those types of conventions, though, we have to remember that we’re messing with that knowledge in the head.

But we have to be careful with conventions as there are many site practices that might be second nature to us and not to our customers. I once watched a usability session where on-screen instructions directed the customer (a 40ish or so middle class man) to select “the drop-down box.” He searched around the page looking for a box labeled “drop-down” and didn’t find one. That terminology wasn’t familiar to him. Some of our everyday language isn’t as common as we might assume.


While many of the concepts from Don Norman’s book have already seriously changed the way I look at the world (I think my wife may be getting annoyed at my now constant commentary on the design of every door we see), I most appreciate the relatively simple concepts of “knowledge in the head” and “knowledge in the world.” Forcing ourselves to identify what elements of our sites’ designs require which of those concepts will lead us to create significantly more usable sites for our customers. And more usable sites will absolutely lead to more sales. Woo hoo! Bonuses for all!

What do you think? Do you see your site differently in the context of these concepts? Do you have other concepts you like to use?


  • By John H, April 9, 2010 @ 8:15 am

    Thanks for this post, Kevin. After reading this yesterday I spent some time going through my site trying to understand how much “knowledge in the head” we are asking our customers to have. I was unpleasantly surprised with how much we’re asking of our customers. We have some work to do. I ordered Design of Everyday Things last night. Can’t wait to read it. Do you have any other book recommendations?

  • By Kevin Ertell, April 9, 2010 @ 10:26 am

    Thanks for your comment, John. I’m glad you were able to find some areas to improve. A couple of other books you might consider are “Don’t Make Me Think” by Steve Krug (http://www.amazon.com/Think-Common-Sense-Approach-Usability/dp/0789723107) and “Usability Engineering” by Jakob Nielsen (http://www.amazon.com/Usability-Engineering-Interactive-Technologies-Nielsen/dp/0125184069/ref=sr_1_2?ie=UTF8&s=books&qid=1270826677&sr=1-2-spell) or really anything by Jakob Nielsen.

  • By Larry Allen, April 9, 2010 @ 10:51 am

    Another great post, Kevin. Just RT’d a line from this blog: “The reality is, we are not like our customers.” So true, and yet so often overlooked, not only re: web design, but in every form of retail design…from store design to merch mix to customer service.

    In over 25 years of retailing, I have seen (and been guilty myself of doing it) this happening over and over. Even in situations where it is painfully obvious (can you imagine a bunch of middle aged men making purchase assortment decisions in fashion footwear?).

    Thanks for reminding us all of this very important point!

  • By Jennifer B., April 9, 2010 @ 1:14 pm

    One more point I’d add about conventions.

    We have to be careful of them for another reason: sometimes a practice that actually reflects exceedingly poor usability gains a foothold because one site follows another and pretty soon it’s “the way it’s done”.

    Even if a certain convention is established enough to be knowledge in the head for most of customers, I think it sometimes warrants a second glance. Otherwise we never move past some of the really grievous executions out there of web features and functionalities.

    I would rather introduce a reasonable learning curve for customers but the payoff be a great user experience than to blindly follow conventions that were established because “everyone else was doing it”.

    Some conventions need to be decommissioned.

  • By Kevin Ertell, April 9, 2010 @ 2:57 pm

    Thanks for your comments, Larry and Jennifer.

    Larry: I completely agree with your points about these concepts applying well beyond websites. It’s so easy to get carried away with a design process and forget that we can’t possibly have our customers’ perspectives. Heck, even if we were customers before joining the company, one day into our new jobs and we already have a lot more “knowledge in the head” than our customers do.

    I also like your visual of the bunch of middle-aged guys determining the right fashion footwear assortments. Nice one!

    Jennifer: I think you make an excellent point about conventions. Continuous improvements can lead to changing some conventions for the better, for sure. Thanks for making that point!

  • By Jason Stewart, April 19, 2010 @ 9:17 am

    Kevin, great post (as always). I wanted to echo Jennifer’s point about decommissioning some conventions. I heard Dan Saffer say “Best practices should be a place to begin, not to end” at Interaction ’09, it’s stuck in head ever since. It can be tricky in the retail world, as you mentioned in your post, to mess with “knowledge in the head”, but unless interaction designers actually do deviate from convention from time to time we’d never see an improvement in the way we do sometimes-cumbersome-things. For example, drop-down menus, while effective for short lists, become daunting when the list is long and you’re not sure which item matches what you think you should select (think of those drop downs asking you what your job title is; I never see Usability Auditor!). Instead, text fields with Auto-Complete functionality can offer greater flexibility in these situations proactively narrowing the list of options (which is now limitless since it doesn’t have to be displayed in a drop-down) based on what the visitor has typed. While a deviation from convention, the benefits of being able to offer a large number of items from which to choose while not overwhelming visitors with a vast number of options outweighs the learning curve involved to use it. What do you think?

    Nonetheless, the two usability points you brought up are excellent places to start one’s usability journey!

  • By Drew Bennett, April 23, 2010 @ 5:19 pm


    I wish I could find as much time as you to read but I love this post. The line about not being like our customers is a classic and should be bolted to the notion of “our opinions, although interesting, are irrelevant”. I don’t write checks to our business, our customers do. WE do not build sites for us, we build them for customers.

    I think the point about the value and importance of service really is best illustrated through excellent usability. It is far too easy to forget that the customer is essentially “alone” when on the site. Familiarity that is positive is good (positive convention) while familiarity that is bad (negative/confusing convention) should be dropped or revised. Krug makes similar points in his UX classic, “Don’t Make me think”. The customer experience (CX) to a significant degree is managed through the UI/UX.

    This is especially important in Business to Business tools. Rarely is someone from Oracle, Salesforce or Microsoft sitting next to the user while they engage with the application. The points you raise are equally powerful to that market, what is your application telling your customer and how effectively can they buy into long term use and satisfaction with it?

    Great read as always!

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