Tag Archives: ergonomics

Electronic Books–A Human Factors perspective

So I finally made the plunge and obtained an Amazon Kindle E-book reader.  This isn’t a gadget review site so don’t expect a full review but I just wanted to comment on some of the ergonomic/human factors considerations after using the device for the past few days.  The bottom line?  There are some critical “book behaviors” that the device does not afford but are critical to me.  My reading material is primarily articles, reference books; not narrative fiction (that typically flows in a linear, page-by-page fashion).

The GOOD:

  1. The hype concerning the display is warranted.  It is extremely high contrast and easy to read even in dim light.  What makes this different from reading on an LCD is that the pixels are actually closer to the reading surface (just like paper).  The pixel density is also very high (167 dpi) compared to LCDs.
  2. The device is very thin and light.  The screen is small but not unusably so.
  3. Search is a nice function.  However, I am not sure if this perfectly replaces book indexes.  With an index, you can rely on recognition instead of free recall (necessary in search).
  4. Built-in 3G wireless for free.
  5. The software is very simple and the navigation is easy.  It is similar to an ATM with soft-options.

The BAD (in no particular order):

  1. Page turning is a bit sluggish (probably .5 to 1 second).  I don’t have empirical data to back up actual “performance” differences but it bothers me.
  2. The page forward and backward buttons are too easily pressed when you pick the device up (not a big deal but an inconvenience).
  3. I can dog-ear pages and include notes on pages or passages.  My notes are accessible as a text file for use later.  However, the text file is sort of meaningless.  While my note is there, it is devoid of context (I don’t know where it goes).  It would be nice if this functionality was improved.
  4. The on-off switch is located on the back of the device.  So when I want to turn it off, I always inadvertently jump a page or two.
  5. Instead of using page numbers to navigate the text, it uses something called “Locations.”  I still have not figured out what this is.  At the bottom of the screen, it might display, “Locations 203-15”.  Are these lines?  Paragraphs?  Pages?
  6. There is the “previous page” button, but also a “Back” button…and they seem to function similarly under some circumstances but differently in others.

Anne and I are writing a book and I’ve been doing quite a bit of research with articles and books.  Typically, I will read a page from a book or article and make notes.  Currently, there is not an easy way to export these notes or even email them to myself from the device.  As I mentioned, the notes it creates are unusable.  Another big thing is that I cannot open multiple books or articles at once–this is a problem with the whole class of devices, not just the Kindle.

These are just some of my recent thoughts on the device.  The tentative bottom-line is that I probably won’t be buying expensive reference books on the device (it just can’t yet replace a paper book for my use cases).  But reading PDF articles and Word .docs is quite pleasant.

Here are some pictures (the device and the device’s text presentation compared to a real book).

Kindle text compared to real print

Inner and Outer Outed

Redesigned Beltline signs to drop ‘Inner’ and ‘Outer’

RALEIGH – No more “Inner” and “Outer” for Raleigh’s Beltline. Soon it will be Interstate 40 and Interstate 440, east and west.

The state Department of Transportation is about to make good on a long-standing promise to get rid of the Inner Beltline and Outer Beltline signs that get lots of motorists mad, confused and lost.

This human factors redesign feels personal. I’ve bemoaned the difficulties with the Raleigh loop signs for as long as I’ve lived here. I know people who have no trouble with it, but I am incapable of translating “inner” or “outer” into actual directions, especially during the multi-tasking required for driving toward an entrance ramp and thinking about where my destination is in relation to my current position.

I think the greatest difficulty comes from translation. To know which way the inner beltline goes, the driver must mentally step through the following (at least until s/he just memorizes what ramp to take).

  1. Raleigh is surrounded by a loop with 12 o’clock in the north.
  2. I’m at about the 9 o’clock position approaching an on-ramp from outside the city.
  3. My destination is close to the 4 o’clock position, so it would be best to go right to get there.
  4. Right is….
  5. Right is… uh
  6. Right is inner or outer?
  7. Ok, inner means inside the outer. In the U.S. cars go in prescribed directions on certain sides of the street, so looking down at the beltline I can expect cars on the inner side to be going north from where I am.
  8. Wait, is that true 180 degrees on the other side of the circle? I think so…
  9. So that means that the inner beltline is going clockwise?
  10. That means that the outer beltline goes counter clockwise which is to the right and where I want to go
  11. I want the counter clockwise entrance
  12. The counter clockwise entrance is the outer beltline

No wonder I’m always late.

For a bonus, don’t miss out on the typical “common sense” comments attached to the News & Observer article.

Human Factors Journal Celebrates 50 Years With Special Issue Highlighting Pivotal Research and Applications

The journal, Human Factors, is celebrating its 50th anniversary with a retrospective of some pivotal research and areas. To celebrate, the entire issue is available online for free. Some highlights:

  • The Split Keyboard: An Ergonomics Success Story
  • The Role of Expertise Research and Human Factors in Capturing, Explaining, and Producing Superior Performance
  • Multiple Resources and Mental Workload
  • Putting the Brain to Work: Neuroergonomics Past, Present, and Future
  • Discoveries and Developments in Human-Computer Interaction
  • Aging and Human Performance

Human Factors and Ergonomics Society : Human Factors Journal Celebrates 50 Years With Special Issue Highlighting Pivotal Research and Applications

Ergonomics for kids

Ergonomics for kids is a relatively recent area of research.  This new paper addresses childhood ergonomics during computer usage.

A new study by human factors researchers in Australia suggests that students’ posture is affected by the height at which they view classroom learning materials. The researchers cited computer screen displays positioned at mid-level as causing less musculoskeletal strain than high- and book-level displays. Their findings were published in the February 2008 issue of Human Factors: The Journal of the Human Factors and Ergonomics Society.

The rapid increase in computer use by children over the past few years, say the authors, “has outpaced the development of knowledge about the ramifications for the health of children.” For example, data from the Australian Bureau of Statistics indicate that in 2006, 80% of children aged 5 to 14 years used a computer at home.

Human Factors and Ergonomics Society : Research Suggests Mid-Level Computer Screen Displays Can Minimize Musculoskeletal Strain in Schoolchildren

[full text PDF]

Trust in Automation

I’ve heard a great deal about trust and automation over the years, but this has to be my favorite new example of over-reliance on a system.

GPS routed bus under bridge, company says
“The driver of the bus carrying the Garfield High School girls softball team that hit a brick and concrete footbridge was using a GPS navigation system that routed the tall bus under the 9-foot bridge, the charter company’s president said Thursday.Steve Abegg, president of Journey Lines in Lynnwood, said the off-the-shelf navigation unit had settings for car, motorcycle, bus or truck. Although the unit was set for a bus, it chose a route through the Washington Park Arboretum that did not provide enough clearance for the nearly 12-foot-high vehicle, Abegg said. The driver told police he did not see the flashing lights or yellow sign posting the bridge height.

“We haven’t really had serious problems with anything, but here it’s presented a problem that we didn’t consider,” Abegg said of the GPS unit. “We just thought it would be a safe route because, why else would they have a selection for a bus?””

Link to original story (with pictures of sheared bus and bridge)

Indeed, why WOULD “they” have a selection for a bus? Here is an excerpt from the manual (Disclosure: I am assuming it’s the same model):

Calculate Routes for – Lets you take full advantage of the routing information built in the City Navigator maps. Some roads have vehicle-based restrictions. For example, a street or gate may be accessible by emergency vehicles only, or a residential street may not allow commercial trucking traffic. By specifying which vehicle type you are driving, you can avoid being routed through an area that is prohibited for your type of vehicle. Likewise, the ******** III may give you access to roads or turns that wouldn’t be available to normal traffic. The following options are available:

  • Car/Motorcycle
  • Truck (large semi-tractor/trailer
  • Bus
  • Emergency (ambulance, fire department, police, etc.)
  • Taxi
  • Delivery (delivery vehicles)
  • Bicycle (avoids routing through interstates and major highways)
  • Pedestrian”

gps-screen.gif

If we can assume no automation can be 100% reliable, at what point to people put too much trust in the system? At what point do they ignore the system in favor of more difficult methods, such as a paper map?At what point is a system so misleading that it should not be offered at all? Sanchez (2006) addressed this question and related type and timing of error to amount of trust placed in the automation. Trust declined sharply (for a time) after an error, so we may assume the Seattle driver might have re-checked the route manually had other (less catastrophic) errors occurred in the past.*

The spokesman for the GPS company is quoted in the above article as stating:

“Stoplights aren’t in our databases, either, but you’re still expected to stop for stoplights.”

I didn’t read the whole manual, but I’m pretty sure it doesn’t say the GPS would warn you of stoplights, a closer analogy to the actual feature that contributed to the accident. This is a time where an apology and a promise of re-design might serve the company better than blaming their users.

*Not a good strategy for preventing accidents!

Other sources for information on trust and reliability of automated systems:

Lee, J.D. & See, K.A. (2004). Trust in Automation: Designing for Appropriate Reliance. Human Factors, 46, 50-80.

Parasuraman, R. & Riley, V. (1997). Humans and automation: use, misuse, disuse, abuse. Human Factors, 39, 230-253.

Wiegmann, D. A., Rich, A., Zhang, H. (2001). Automated diagnostic aids: the effects of aid reliability on users’ trust and reliance. Theoretical Issues in Ergonomics Science, 2(4), 352-367.

The Cognitive Engineering Laboratory

John Wayne, United Airways, and Human Factors

Most everyone probably heard about the gun accidentally fired in the passenger plan cockpit last week.

But did you hear about the designs that lead to this human error?

I had to do some detective work (and quizzing gun owners) to find the following pictures:

Here is the gun in question (or similar enough) showing the safety and the spaces in front of and behind the trigger.

pilotgun.jpg

Pilots keep the gun in a hoster (see below).

Users report some difficulty ascertaining whether the gun is “locked” into the holster. If it is not, then the trigger can be in an unexpected place (namely, higher in the holster than the shaped holster seems to indicate.)

The TSA requires pilots who have been issued these guns to padlock the trigger for every takeoff and landing. Reports are that pilots do this about 10 times for a shift. Therefore, let’s assume we have 10 chances for error in using the holster and in using the padlock.

tsaholster.jpg

The padlock goes through the trigger. It should go behind, to keep anyone from pulling the trigger. If the gun is 100% in the holster, this is the case. If it is not… then the padlock can end up in FRONT of the trigger. The opaque holster prevents a visual check of the trigger.

The holster also prevents a visual check of the safety.

All of this might be forgiven, or addressed with training, if it weren’t for the fact that there are numerous other ways to prevent a gun from firing rather than locking something through the trigger. Remember, we should be on the “Guard” step of “Design out, Guard, then Train.”

I’m not even going to discuss whether pilots should have guns.

“Boyd said he supports the program to arm pilots, saying, “if somebody who has the ability to fly a 747 across the Pacific wants a gun, you give it to them.”

For an amusing take, see “Trust is not Transitive.”

Electronic voting machines and misconceptions…

There was a report on electronic voting irregularities in South Carolina (during the Republican primaries last week) this morning on NPR.  The person that was interviewed,a representative of the State Election Commission, naively stated that the machines were fine, but it was the users who were not following operating procedures. Here is a quote:

“Any voting system is dependent on its user following the proper operating procedures and, in this case, Horry County election officials missed a step,” he says. That step was closing out tests performed on the machines before the elections, which left some test votes still recorded and any affected machine locked up.

Unfortunately, this widespread view of blaming the user prevents designers and engineers from coming up with easier to use voting machines. If the problem lies with the user, the manufacturer/designer is off the hook in terms of fixing the problem.

From a user-centered design perspective (which has roots in human factors), you never blame the user!  With the prevalence of voting system usability issues in the news, clearly, there are no usability or human factors people working within the manufacturers of electronic voting systems.

[link to NPR story; text or streaming audio]

However, there is some hope. Human factors researchers Tiffany Jastrzembski and Neil Charness, at Florida State University, examined electronic voting machines to improve accuracy among older adults. The article, published in Ergonomics in Design, is a good example of applying the science of human factors to human-machine problems.

[link to press release and full text article]

Automation, Consumer Products, and Energy Usage

Interesting article on the use of automated decision aids on consumer devices. The researchers used a vacuum cleaner that indicated when an area needed more cleaning or not. They wanted to determine if users would use less energy if they were told that an area was clean. They found that energy consumption was not reduced. This is contrasted with some research (I can’t think of the exact citation) that showed that when users saw their household energy consumption, they tended to be more mindful about reducing their usage.

Sauer, J., & Ruttinger, B. (2007). Automation and decision support in interactive consumer products. Ergonomics, 50, 902 – 919.

Abstract. This article presents two empirical studies (n = 30, n = 48) that are concerned with different forms of automation in interactive consumer products. The goal of the studies was to evaluate the effectiveness of two types of automation: perceptual augmentation (i.e. supporting users’ information acquisition and analysis); and control integration (i.e. supporting users’ action selection and implementation). Furthermore, the effectiveness of on-product information (i.e. labels attached to product) in supporting automation design was evaluated. The findings suggested greater benefits for automation in control integration than in perceptual augmentation alone, which may be partly due to the specific requirements of consumer product usage. If employed appropriately, on-product information can be a helpful means of information conveyance. The article discusses the implications of automation design in interactive consumer products while drawing on automation models from the work environment.