Category Archives: ergonomics

Thoughtful and Fun Interfaces in the Reykjavik City Museum

I stopped over in Iceland on the way to a conference and popped in to the Reykjavik City Museum, not knowing what I’d find. I love the idea of technology in a museum, but I’m usually disappointed. Either the concepts are bad, the technology is silly (press a button, light some text), or it just doesn’t work, beaten into submission by armies of 4-year-olds.

Not at the Settlement Exhibit in Reykjavik. There are two unique interfaces I want to cover, but I’ll start at the beginning with a more typical touchscreen that controlled a larger wall display. As you enter the museum, there are multiple stations for reading pages of the Sagas. These are the stories of their history, from the 9th to 11th centuries, and beautifully illustrated.
They have been scanned, so you can browse the pages (with translations) and not damage them. I didn’t have all day to spend there, but after starting some of the Sagas, I wished I had.

Further in you see the reason for the location: the excavation of the oldest known structure in Iceland, a longhouse, is in the museum! Around it are typical displays with text and audio, explaining the structure and what life was like at that time.

Then I moved into a smaller dark room with an attractive lit podium (see video below). You could touch it, and it controlled the large display on the wall. The display showed the longhouse as a 3-D virtual reconstruction. As you moved your finger around the circles on the podium, the camera rotated so you could get a good look at all parts of the longhouse. As you moved between circles, a short audio would play to introduce you to the next section. Each circle controlled the longhouse display, but the closer to the center the more “inside” the structure you can see. Fortunately, I found someone else made a better video of the interaction than I did:

The last display was simple, but took planning and thought. Near the exit was a large table display of the longhouse. It was also a touch interface, where you could put your hand on the table to activate information about how parts of the house were used. Think of the challenges: when I was there, it was surrounded by 10 people, all touching it at once. We were all looking for information in different languages. It has to be low enough for everyone to see, but not so low it’s hard to touch. Overall, they did a great job.

Be sure to do a stopover if you cross the Atlantic!

Both videos come from Alex Martire on YouTube.

Helmet Design and Environment Interaction

I wanted a new helmet that offered some side-impact protection to replace my trusty Petzl Ecrin Roc, especially after a helmet-less Slovenian climber mocked me in Italy for wearing “such a heavy helmet” at a sport climbing crag.

I now own the Petzl Meteor, but after one trip discovered a strange design flaw.

Most helmets clip together the way carseats or backpack buckles clip together:

The Petzl Meteor helmet has a similar clip, but also contains magnets that draw the buckle together. Here is how it should work:

I was climbing at Lover’s Leap in California, a granite cliff. Those of you who know your geology might guess what happens when you combine magnets and iron-rich granite. I put the helmet on the ground while sorting gear, put it back on and heard the buckle snap together. A few minutes later, I looked down (which put some strain on the helmet strap), the buckle popped open, and the helmet fell off my head.

When I examined the buckle, there was grit stuck to the magnet.

Iron grit on magnet
Iron grit on magnet

Wiping it off seemed to work, except that it moved some of it to the sides rather than just the top. My fingers weren’t small enough to wipe it from the sides. So, the next time I snapped it shut and checked to make sure it was locked, I couldn’t get it off. The grit on the side prevented the buckle from pinching enough to release. I was finally able to get it off the sides by using part of a strap to get into the crevices.

Iron grit on sides

I made some videos of the phenomenon. It was pretty easy to do, I just had to put my helmet on the ground for a moment and pick it up again. Attached grit was guaranteed – these are strong magnets!

I am not the only person to notice this:

In one review of another helmet with a similar closure:

The only issue I had with the buckle came after wearing the Sirocco while bolting and cleaning a granite sport route. Some of the swirling granite dust adhered to the magnets, obstructing the clips. It was easy enough to fix: I just wiped the magnets clean, and it has worked perfectly since.


Helmet review from Outdoor Gear Lab

What we found in our tests of both the Meteor and the Sirocco was that the magnet did not always have enough oomph to click both small arms of the buckle completely closed. About one in four times, only one of the plastic arms would fasten and the buckle would need an extra squeeze to click the other arm in. Another thing our testers noticed was that the magnet would pick up tiny pebbles which would prevent the buckle from fully closing. The pebbles can be easily cleaned by brushing off the exposed part of the magnet, but it adds an extra step to applying the helmet. The bottom line is, we prefer the simplicity of the old plastic buckle. We think that the magnet is a gimmick which potentially makes a less safe helmet.

Safety gear shouldn’t add steps to be remembered, such as making sure the buckle is locked, even after getting auditory and tactile feedback when one connected it. Some people may never climb in an area with iron in the ground, but the use-case for a granite environment should have been considered. You know, for little climbing areas such as the granite cliffs of Yosemite.

Rock Climbing Human Factors – Harness attachment points

A friend of mine was recently rappelling from a climb, meaning that she had the rope through a device that was connected to her belay loop on her harness. As she rappelled, she yelled that her harness broke, and the waistband of the harness slid nearly to her armpits. Fortunately, she remained calm and collected, and was still able to rappell safely, if awkwardly, to the ground. On the ground, her partner saw that her waistband with belay loop had become disconnected from her leg loops. The leg loops were intact, though a keeper-strap that helps the leg loops stay centered was no longer connected.

So, what happened?

First, for the non-climbers, a primer. A climbing harness is composed of three major parts, attached to each other in various ways depending on the manufacturer. The first part is the waistband, which is load-bearing, meaning that it is meant to take the weight of a climber.

The second part of the harness is the belay loop, a load-bearing stitched circle that connects the waistband and leg loops and is also used to hold a belay device, to hold the climber’s weight when rappelling, and for anchoring to the ground or a wall when needed.

The last part of the harness is the leg loops, which are also load-bearing in the parts that connect to the belay loop and around the legs themselves.

Figure 1 shows the general composition of climbing harnesses, with these three parts diagrammed in the Base Concept.

Figure 1. Simplified diagrams of climbing harnesses.

On most harnesses, the leg loops are kept connected to the belay loop by a “keeper strap.” This is usually a weak connection not meant to bear weight, but only to keep the leg loops centered on the harness (shown in blue in figure 1). In the case study that prompted this blog post, the keeper strap was connected through the belay loop, rather than the full-strength leg loops (figure 2.) When loaded, it came apart, separating the leg loops from the waistbelt. My own tests found that the keeper strap can be very strong, when it is loaded on the strap itself. But if the leg loops move so that the keeper buckle is loaded by the belay loop, it comes apart easily.

Figure 2. Harness assembled with keeper strap bearing weight via the belay loop.

There are two ways to mis-attach leg loops to the belay loop of a harness. The first way is by connecting the leg loops back to the harness, after they were removed, using the keeper strap. The video below demonstrates this possibility. Once connected, the harness fits well and gives little indication the leg loops are not actually connected to bear weight.

The second (and I think more likely) way is by having the leg loops disconnected from the back of the harness, usually for a bathroom break or to get in and out of the harness. The leg loops are still connected in the front of the harness, but if a leg loop passes through the belay loop, suddenly the keeper strap is load bearing when the leg loops flip around. However, the harness does not fit differently nor does it look particularly different unless carefully inspected. Video below.

The non-load bearing parts of the harness are what determine the possibility for this error. In figure 1, some harnesses either do not allow disconnection of the leg loops in back or only allow their disconnection in tandem. When the leg loops are connected in this way, the front of the leg loops cannot be passed through the belay loop. Video demonstration below.

Back to figure 1, some harnesses allow the disconnection of leg loops for each leg. If these are disconnected, a loop may be passed through the front belay loop, resulting in the error in figure 2.

In sum, this error can be examined for likelihood and severity. It is not likely that the error occurs, however if it does occur it is likely it will go undiscovered until the keeper strap comes apart. For severity, the error could be lethal, although that is not likely. The waistbelt will hold the climber’s weight and having leg loops and a waistbelt is a (comfortable) redundancy. However, the sudden shock of suddenly losing support from the leg loops could cause loss of control, either for an un-backed-up rappell or while belaying another climber.

What are the alternatives?

  • Climbing is exploding, particularly climbing in gyms. The “gym” harnesses, with fewer components and gear loops (Figure 1), are a good option for most climbers now. However, there is little guidance about what harness one should buy for the gym vs. outdoor versatility so few probably know this harness is a good option.
  • Some harnesses are designed to be load-bearing at all points (i.e., “SafeTech” below). It is impossible to make an error in leg loop attachment.
  • safetech

  • Harnesses with permanently attached leg loops or loops that attach in the back with a single point are unlikely to result in the error.
  • Many climbers reading this are thinking “This would never happen to me” or “You’d have to be an idiot to put your harness together like that” or my usual favorite “If you wanted climbing to be perfectly safe, you shouldn’t even go.” Blaming the victim gives us a feeling of control over our own safety. However, there are other instances where gear was assembled or re-assembled incorrectly with tragic consequences. No one (or their child) deserves to pay with their life for a simple mistake that can be prevented through good design.

    Short Course in Anthropometry

    NPR just ran an extremely detailed article on the importance and study of anthropometry. The topic is the undue stress nursing places on the spine, even when “proper” lifting procedures are followed. Highlighed is the work of Bill Marras (recent Editor of the journal Human Factors), who developed a sensor rig for the forces experienced by the spine. Read for yourself, but if you want the high points:

    “Moving and lifting patients manually is dangerous even for veteran nursing staff, Marras says, for several reasons:

    • The laws of physics dictate that it’s easiest to lift something when it’s close to your body. But nursing employees have to stand at the side of the bed, relatively far from the patient.

    • Nursing employees also often bend over the patient. That’s important, because there’s a chain of bones along the spine, called facet joints, hidden under the little bumps protruding under the skin. Those bones interconnect and help absorb loads when standing straight. Marras says that when nurses lift as they’re bending, those bones disengage and their disks take most of the force. Those forces are “much, much higher than what you’d expect in an assembly line worker,” he says.

    • When nurses keep working under these loads, it causes microscopic tears in the “end plates,” which are films as thin as credit cards above and below each disc. Those tears lead to scar tissue, which can block the flow of nutrients into the disks — until, eventually, the disks start to collapse. “You could be doing this damage [to your back] for weeks or months or years, and never realize it,” says Marras. “The event that caused you to feel the problem is just the straw that broke the camel’s back.”

    The final conclusion was that people cannot lift other people safely. Assistive machines are needed, and as the article points out, hospitals do not have them.

    Nonagenarian designs for aging and inspires younger designers

    Barbara Beskind, 90, is a designer at IDEO who works with engineers on products that improve the quality of life for older people. Nicolas Zurcher/Courtesy of IDEO
    Barbara Beskind, 90, is a designer at IDEO who works with engineers on products that improve the quality of life for older people.
    Nicolas Zurcher/Courtesy of IDEO

    NPR published a great story on Barbara Beskind, a product and interface designer in her early nineties.

    My favorite excerpt:

    Gretchen Addi, an associate partner at IDEO, hired Beskind. Addi says when Beskind is in a room, young designers do think differently. For example, Addi says IDEO is working with a Japanese company on glasses to replace bifocals. With a simple hand gesture, the glasses will turn from the farsighted prescription to the nearsighted one.

    Initially, the designers wanted to put small changeable batteries in the new glasses. Beskind pointed out to them that old fingers are not that nimble.

    “It really caused the design team to reflect,” Addi says. They realized they could design the glasses in a way that avoided the battery problem. “Maybe it’s just a USB connection. Are there ways that we can think about this differently?”

    There are several wonderful take-home messages:

    • Creative and fulfilling work can extend late into the lifetime
    • Aging does not just bring limitations, it also extends perspective and wisdom
    • Designing for aging is doesn’t detract from a product but can enhance it for people of all ages
    • Having a person with such perspective on a design team changes the perspective and thoughts of the rest of the team, the core tenant of participatory design

    Worst Mobile Interface Ever

    I was reading articles the other day and came across a site that, as many do, reformatted for my phone. Almost all reformatted-for-mobile sites are terrible, but this one is my favorite.
    You cannot scroll through the 21 page article by moving your finger up and down, as would happen on a website. The only way to change pages is via the horizontal slider at the bottom. Good luck trying to move it so slightly it only goes forward one page! And yes, moving the slider left and right does move the page up and down.

    Usability process not used for ACA website

    slideA recently released report, done in March 2013, reveals the process of creating Hindsight is always 20/20, but we’ve also worked hard to establish best practices for considering both engineering and the user in software development. These contributions need to be valued, especially for large scale projects. After looking through the slides, one thing I note is that even this improved approach barely mentions the end users of the website. There is one slide that states “Identify consumer paths; review and modify vignettes.” The two examples of this are users who have more or less complex needs when signing up for insurance. I don’t see any mention of involving actual users prior to release.

    The NPR write-up states:

    Consultants noted there was no clear leader in charge of this project, which we now know contributed to its disastrous release. And there was no “end-to-end testing” of its full implementation, something we now know never happened.

    Some of this may fall on us, for not being convincing enough that human factors methods are worth the investment. How much would the public be willing to pay for a solid usability team to work with the website developers?

    Potpourri–Lazy Summer Edition

    It’s summer and we (along with some of you) are taking a break.  But here’s a list of interesting usability/HF-related things that have crossed my path:

    • After much complaining, Ford is bringing back physical knobs in their MyTouch in-car controls.  Anne and I worked on some research (PDF) in our past lives as graduate students that directly compared touch-only interfaces to knob-based interfaces so it’s nice to see it is still a major issue; if only Ford read our 9 year old paper 🙂
    • Trucks driving under very low bridges is such a large problem in Australia that they are deploying a really novel and clever warning system.  A waterfall that projects a sign that’s hard to miss!
    • tags_finderApple will introduce their next version of OSX in the fall. One of the features i’m most excited about is system-level tag support.  Tags allow users to organize their files regardless of location or type.  I’m particularly interested in personal, single-user-generated tagging (compared to collaborative tagging like that used in flickr) as it appears to benefit older adults information organization and retrieval (PDF).  This pleases me.

    The Other Father of Human Factors: John E. Karlin

    Paul M. Fitts is widely regarded as the father of human factors.  He gets mentioned a lot in HF texts because of his (still influential) law.  In more modern times, Donald Norman gets a lot of recognition as the author of the Design of Everyday Things (mentioned in my post below) which introduced the idea of psychology and human factors to a more mainstream audience.  However, someone who never gets mentioned (in my 12 years of education i’ve seen him mentioned once) was John E. Karlin who recently passed away.

    By all accounts a modest man despite his variegated accomplishments (he had a doctorate in mathematical psychology, was trained in electrical engineering and had been a professional violinist), Mr. Karlin, who died on Jan. 28, at 94, was virtually unknown to the general public.

    He is still relatively unknown to HF only because he rarely published his results; instead, he worked to solve problems in industry using the scientific method that all psychologists use.

    “He was the one who introduced the notion that behavioral sciences could answer some questions about telephone design,” Ed Israelski, an engineer who worked under Mr. Karlin at Bell Labs in the 1970s, said in a telephone interview on Wednesday.

    The NYT recently posted an obit detailing his contributions including such fundamental ones such as the telephone numeric layout (different from calculator layout):

    Putting “1-2-3” on the pad’s top row instead of the bottom (the configuration used, then as now, on adding machines and calculators) was also born of Mr. Karlin’s group: they found it made for more accurate dialing.

    The piece is very well written and I’m a little surprised that the author actually seems to understand HF and how it’s unique from other things (emphasis added):

    It is not so much that Mr. Karlin trained midcentury Americans how to use the telephone. It is, rather, that by studying the psychological capabilities and limitations of ordinary people, he trained the telephone, then a rapidly proliferating but still fairly novel technology, to assume optimal form for use by midcentury Americans.

    (NYT: great article but you hyphenated human factors in the 10th paragraph)

    Go read it!