Category Archives: affordances

No one wants to touch the gas pump


The above is from a gas pump in a large metro area. Can you guess the most common zip code number? How about what object people use to to press the keys?
But you’re probably missing my favorite part – look in the lower right. Do you see the black electrical tape? Under that tape is the START button for the gasoline. The instructions on the screen say to “press the start button to begin fueling.” As the most commonly pressed button it was the first to be destroyed, and the station attendant’s tape solution earned it a humor tag in this post. I’m also willing to bet that hiding the START button is why the “No/Cancel” button has been furiously destroyed as well.

I’ve come across some of these where the soft keypads were entirely destroyed by keys for the common zip code numbers. Once I had to leave to find another gas station, since it wouldn’t accept my card without a zip code entered and the buttons no longer worked.

Photo credit Maribeth Gandy Coleman

Innate number sense changes with age

New research shows that our ability to rapidly estimate the number of things in a set (an ability called subitizing) peaks around 30 and declines with age.  Researchers posted an experiment online to measure this “number sense”.

This could have implications for the design of displays that require decision making based on judgements of the number of things.  A simple example might be comparing the star ratings on products when shopping online.

The team found that scores on the test improved gradually throughout the school years, peaking around age 30, then declining. Nonetheless, there were large individual differences in scores among people of the same age. Those differences appeared to be modestly linked to school performance: Those with the best innate number sense reported the highest ability in math in school. A subgroup of nearly 500 subjects were also asked to report their math scores on the SAT. Again, a higher innate numbers sense was associated with higher SAT scores.

Lack of human factors = more of your tax dollars at “work”

I live in Raleigh, NC. Our area code has always been a little problematic for the nationwide 911 emergency system – it is 919. But at least until now, dialing the 919 for a local call was optional. Looks like we’re finally big enough for ten digit dialing and we can expect to pay the price in our public safety system.  Check out this email from the Director of Emergency Communications, particularly the part about dispatching officers every 7.5 minutes to investigate hang-ups:

I am sure by now that you have seen or heard about some of the impact that the new 10 digit dialing requirement has made upon our 9-1-1 center. Unfortunately, we are almost three weeks downstream from this implementation, and are seeing few signs of improvement.

Neither the 9-1-1 center, the city, or the local telephone carriers are responsible for selecting area codes. They are distributed according to a national plan. “Overlays” are added when a region begins to run out of numbers in their original pool; in this case 9-1-9. Unfortunately, with the similarity between 9-1-9 and 9-1-1, our agency has seen this issue in the past, as some of our citizens have utilized 10 digit dialing for some time. The current impact on our staff – and on law enforcement – is that on our peak days we are dispatching officers to investigate hang up calls once every seven and a half minutes. Of course, this is a daily average, meaning that at peak times the impact is even more severe. Plus, we only dispatch calls that we can’t resolve another way. Many people who misdial don’t realize they have until we answer. Others hang-up, but answer when we call them back. In such cases sending an officer is not required, so the total number of calls we receive in error far exceeds those dispatched.

As Director of Emergency Communications, I am asking for your help. We have identified that a majority of such calls come from either senior citizens or business telephones. In the first case, confusion over the proper procedures seems to be the norm.  After 40 years, folks now have to dial 10 digits just to talk to their neighbor. We’ve had callers tell us they thought they had to now dial 9-1-1 before calling in our area, and others ask if they needed to dial 9-1-9 before they called 9-1-1. If you have an elderly friend, relative, or neighbor, I’d like to personally ask you to take the time to make sure they understand to carefully dial “9-1-9” when required. I believe that with some patience and understanding we can make significant inroads.

With regard to business telephones, the issue is a little more complex, and may in some cases even involve the need to dial “9” to get an outside line, followed by the unnecessary “1” before dialing the area code. Whatever the reason, it really boils down to just taking a few extra seconds to make sure of the numbers you’re dialing. Whether you work at a local business, or own one, can I please also count on you to assure that your co-workers use due care when calling? This is a very serious issue and takes resources away from dealing with actual emergencies.

So, to summarize:

  • There is a lack of understanding when to use 10-digit dialing.
  • Being “careful” is not going to fix this problem.
  • The added traditions for businesses to dial “9” to get out adds to the problem (NC State moved to a dial “7” system, presumably for this reason).
  • Those with a lifetime of 7-digit experience, and presumably the least likely to have numbers pre-programmed into a cell phone, make the most errors.

The issues here are fascinating, yet predictable. I don’t know if there is a perfect answer, since changing the long-term ill-chosen area code would be confusing (although my home town in Alabama has gone through 3 such changes in the last couple of decades – from 205 to 334 to 251!). But it is clear that we are penalized by the similarity of our numbers to a national standard for emergency calls. I applaud the tone of the email, which is not blameful – just desperate for a solution. However, I have great skepticism that advising “due care” in dialing will make any difference at all.

Older adults and Windows 8

In an earlier post we discussed how illuminating simple user testing can be. The video below is computer blogger Chris Pirrilo who put his dad in front of the new Windows 8 Preview. The dad seems to be relatively sophisticated and knows about Windows 7 but is completely flummoxed by Windows 8 new “Metro” interface.

Note that this is the reaction of just one person but we shouldn’t discount it. Plenty of users (both young and old) are not as sophisticated as you and I. I guess Anne and I (and other human factors & aging researchers) will still have lots of work!

(via Daring Fireball)

Looking down the barrel of a gun

Here is a design that requires disobedience of the fundamental rule in a sport: don’t point your gun at someone you don’t plan to shoot. Blogger Mark Shead posits it might be due to a lack of domain knowlege by the designer and extends the analogy to software design.

Mistakes in software design aren’t always as easy to spot, but often it comes down to the same thing. To design something you must have at least a basic level of domain knowledge.  That doesn’t means you have to be a world famous chef in order to write a recipe webapp, but you need to make sure you at least know the basics.

Read the full post discussing this design.

“I wasn’t trying to make a computer interface, I was just trying to make a drum” – NPR interviews Bill Buxton

NPR interviews Bill Buxton on the technology side and Sherry Turkle on the social impacts side.

The Touchy-Feely Future Of Technology


“I wasn’t trying to make a computer interface, I was just trying to make a drum,” Buxton tells NPR’s Robert Siegel. “Did I envision what was going to happen today, that it would be in everybody’s pocket — in their smartphone? Absolutely not. Did we realize that things were going to be different, that you could do things that we never imagined? … Absolutely.”

Today, Buxton is known as a pioneer in human-computer interaction, a field of computer science that has seen a spike in consumer demand thanks to a new, seemingly ubiquitous technology: Touch.”

“Turkle says that’s because touch-screen devices appeal to a sentiment that pretty much everyone can relate to: the desire to be a kid again.

“[The] fantasy of using your body to control the virtual is a child’s fantasy of their body being connected to the world,” Turkle says. “That’s the child’s earliest experience of the world and it kind of gets broken up by the reality that you’re separate from the world. And what these phones do is bring back that fantasy in the most primitive way.”

And Turkle warns that living in that fantasy world could mean missing out on the real world around you.”



Photo credit at Flickr.

Learning to use a steering wheel with no vision or feedback

Here is a link to an enjoyable radioshow called “99% invisible,” about the “design, architecture & the 99% invisible activity that shapes our world.”*

99% Invisible-37- The Steering Wheel

This episode covers the difficulty people have in correctly miming use of a steering wheel (spoiler: they can’t!) and how they can learn to do so correctly with no visual feedback. The researcher interviewed was Steven Cloete, whose website can be found here with more information about research specifics.

99% invisible was recently featured on Radiolab, one of my favorite science podcasts.

*no relation to the 99%.


Image credit ryanready at Flickr

Beyond Touch: the future of interaction

Follow the link to read “A Brief Rant on the Future of Interaction Design” by Bret Victor. The briefest of summaries would be that we over-use simple touch in our visions of the future, when we could be including many other cues, such as weight and balance.

From the post:

If you’re with me so far, maybe I can nudge you one step further. Look down at your hands. Are they attached to anything? Yes — you’ve got arms! And shoulders, and a torso, and legs, and feet! And they all move!

Any dancer or doctor knows full well what an incredibly expressive device your body is. 300 joints! 600 muscles! Hundreds of degrees of freedom!

The next time you make breakfast, pay attention to the exquisitely intricate choreography of opening cupboards and pouring the milk — notice how your limbs move in space, how effortlessly you use your weight and balance. The only reason your mind doesn’t explode every morning from the sheer awesomeness of your balletic achievement is that everyone else in the world can do this as well.

With an entire body at your command, do you seriously think the Future Of Interaction should be a single finger?



Photo credit jstarpl @ Flickr

Don Norman Chimes in on Scrolling Direction

Touch Usability points to a nice Don Norman post about new gesture scrolling differences primarily instigated by Apple.  As a side note, i’ve fully converted to the “content moves” model (at home, work, laptop) and did not find the transition unusual at all.  As Norman notes, it just required a subtle mental shift in my model:

Both models are correct in the sense that both make logical sense. The “correct” answer is that the method of scrolling should match the user’s conceptual model of the activity (usually called the user’s mental model). Whichever method is adopted then requires that all people learn to see the world through that particular conceptual model.

It helps that I use all Macs (with Magic Trackpads and Magic Mice).  When I move to a PC, the switch back to “old world” scrolling is almost effortless after a quick re-orientation.