Category Archives: history

“All Too Human” Now Available

I remember the day I discovered human factors. I took the course as an elective, because I’d already taken every other psychology class available to me.  At the time, I knew I loved psychology but also knew I didn’t want to be a clinician or a counselor. The first day, we were assigned a typical “bad design” project – find a frustrating object in the world and write about what was wrong with it. The hardest part of the assignment was limiting myself to one bad design – I had a grievance list pages long. I knew then that I had found a field that matched my desire to ‘fix’ the world.

So many of us who work in human factors had a similar epiphany, and yet our field is virtually unknown to the public. I wanted to change that by writing the kind of non-fiction book I like to read: jargon-free content augmented by stories from history, the news, and the author’s own experiences.

This month my book was published by Cambridge University Press:  All Too Human. The intended audience spans the general public, students, and practitioners in related fields like engineering and computer science.

The Process

I began this project over three years ago. For my cognitive class (undergraduate), I wrote chapters to show the application of basic processes: perception, attention, memory. For my human factors psychology course (graduate), I wanted to tell stories that paired with the primary source readings and spurred discussion.

Each semester I user-tested the chapters by having students write reaction papers, and then iterating on the text to make sure I met my three goals: 1) jargon-free and accessible writing, and 2) conveyed the message that to build our world, we must understand the capabilities and limitations of the human mind, and 3) there’s a profession that does just that: human factors psychology. I edited the chapters repeatedly to make them approachable with fun figures and end-of-book notes rather than in-text citations (to keep the text clean and easy to read.)

The Audiences

For educators: At the undergraduate or graduate level, I wrote this book to be a companion to text and lecture. I often use companion texts in my own courses, such as The Design of Everyday Things or Set Phasers on Stun, to grab students’ attention and generate discussion. Email to ask for an examination copy.

For practitioners: I envisioned this book as one you could recommend to co-workers to give them a fun overview of “what we do” and what we can do. I want it to inspire multi-disciplinary conversations. I want others to understand where our recommendations come from.

For non-fiction lovers: This book has a message for you. It is that we can control the design of our human world. Products and systems should work for us, offer us pleasure, efficiency, and safety. But for that to happen, we must demand it. This book will give you the background to help you understand just how much control we deserve, and in how many ways we can influence companies, governments, and ourselves to make a better world.

Where to Buy

Available from all bookstores, including:
Barnes & Noble
Cambridge University Press

Excerpt from the chapter Needles in Haystacks, on signal detection theory:

Sensitive and Specific

In August of 2020 Magawa received the PDSA Gold Medal for bravery and devotion to duty. A native of Tanzania, he was described as brave, friendly, and a determined worker. Over the course of four years, he found thirty-nine buried landmines in Cambodia. In a country with millions of mines there is still a ways to go, but experts like Magawa are on the front lines of mine detection. Also, Magawa is a rat.

A great attribute of mine-seeking rats is their weight. Although this particular species, African giant pouched rats, are very large for rats, they are still too light to trigger a landmine. They are also smart, have noses at least as discerning as the eyesight of pigeons, and are easy to train. Their training is a real rat race – they work about five hours each weekday on learning to discriminate the smell of a landmine from other scents, all for some mashed banana. They indicate finding a mine by stopping and digging with their little paws.

Magawa was trained by the APOPO, a Belgian non-profit with a mouthful of a name (the Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling, which translates to “Anti-Personnel Landmines Removal Product Development”). The rats’ training is extensive and their success is measured in hits, misses, false alarms, and correct rejections, with more available data than the Project SEA HUNT pigeons. Why not just use a metal detector? The answer fits the theme of this chapter: the high cost of false alarms. The ground is full of nonexplosive metal bits and trash and one estimate is that there are 1,000 false alarms per mine found using just detectors. The rats, meanwhile, can only graduate by demonstrating a 100 percent hit rate on four buried mines and no more than one false alarm. The rats have to be both sensitive and specific. The sensitivity rate is calculated as the number of mines they identified in an area created by their handlers divided by the number of total mines in that area. Their specificity is the number of false alarms per 100 square meters – a slightly different calculation than for other signal detection where specificity is the probability of a false alarm. It may be too much to ask of any single rat to be such a perfect performer, so typically every area is searched by a few rats and their combined scores make the final sensitivity and specificity rates for the team.

In a study led by psychologist Alan Poling, a professor at Western Michigan University, the trained rats were taken to Mozambique where they explored 93,400 square kilometers of mine-infested area. The rats found 41 mines. Humans used other tools to check the area as well, like metal detectors, but found no additional mines. The rats succeeded with extreme sensitivity (100 percent hits and zero misses). But what about their specificity? In this real-world test, they had about 0.33 false alarms for every 100 square meters searched (617 false alarms), or about 39,383 fewer than would be expected from a metal-detecting human. My math is undoubtedly a brash generalization, as the mines aren’t distributed equally and differ by country, but in terms of both hits and false alarms the rats are clear winners.

The current need for enforcement of safety regulations

An NPR article reports on safety violations in Kentucky:

In December 2016, Pius “Gene” Hobbs was raking gravel with the Meade County public works crew when a dump truck backed over him. The driver then accelerated forward, hitting him a second time. Hobbs was crushed to death.

The sole eyewitness to the incident said that the dump truck’s backup beeper wasn’t audible at the noisy worksite. The Kentucky State Police trooper on the scene concurred. Hobbs might not have been able to hear the truck coming.

But when Kentucky Occupational Safety and Health arrived, hours later, the inspector tested the beeper on a quiet street and said it wasn’t a problem.

“These shortcomings are very concerning,” says Jordan Barab, a workplace safety expert who served as Deputy Assistant Secretary of Labor for Occupational Safety and Health under President Barack Obama. “Identifying the causes of these incidents is … vitally important.” Otherwise, the employer doesn’t know how to avoid the next incident, he says.

Gene Hobbs’ case is not the exception. In fact, it’s the norm, according to a recent federal audit.

Kentucky is what’s known as a “state plan,” meaning the federal Occupational Safety and Health Administration has authorized it to run its own worker safety program.

Every year, federal OSHA conducts an audit of all 28 state plans to ensure they are “at least as effective” as the federal agency at identifying and preventing workplace hazards.

According to this year’s audit of Kentucky, which covered fiscal year 2017, KY OSH is not meeting that standard. In fact, federal OSHA identified more shortcomings in Kentucky’s program than any other state.

We know that we must have regulations and enforcement of those regulations to have safe environments. Left to our own choices, people tend to choose what appears to be the fastest and easiest options, not the most safe ones. For an interesting read on the history of safety regulation, see this article from the Department of Labor.

In 1898 the Wisconsin bureau reported that it was often difficult to find safety devices that did not reduce efficiency. Sanitary improvements and fire escapes were expensive, which led many employers to resist their adoption. Constant pressure and attention were needed to obtain compliance. Employers objected to the posting of laws in their establishments and some tore them down. The proprietor of a shoe factory with very poor fire escape routes showed “a disposition to defeat” an inspector’s request for more fire escapes, though he complied in the end. A cloak maker who was also found to have inadequate fire escapes went to the extreme of relocating his operation to avoid compliance. Such delays were not uncommon.

When an inspector found abominable conditions in the dipping rooms of a match factory — poorly ventilated rooms filled with poisonous fumes from the liquid phosphorus which made up the match heads — he tried to persuade the operators to make improvements. They objected because of the costs involved and the inspector “left without expecting to see the changes made.” When a machinery manufacturer equipped his ripsaws with guards after an inspection, a reinspection revealed that the employees had removed the guards.

Without regulation, we’ll be back to 1898 in short order.

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!

Blogging APA Division 21: “One Thing at a Time” (but over a really long time)

I held off for a while writing this post because I wanted to make sure I could include media Dr. John Senders included in his talk. I think you’ll agree it was worth the wait!

At the 2010 APA convention, John W. Senders, Ph.D. presented “One Thing at a Time: From Eye Fixations (1951), to Sampling (1954), to Information Theory (1955), to Workload (1959), to Queuing Theory (1964), to Attentional Demand (1966), Followed by a Lapse of 40 Years.” Video of the talk will eventually be posted on the Division 21 website.

Dr. Senders mentioned an eye tracking experiment from the 1950s, before any “eye trackers” existed. The method was to film the eyes of pilots as they scanned each instrument in a cockpit according to instruction. The position of the pilots eyes were coded in the close-up video. For example, a pilot might be told to “look at the altimeter,” and then the exact position of the pilot’s eyes was coded as “looking at altimeter.” Then, when the pilots were using their instruments naturally, a video of this use could be coded by eye position to know exactly when and where they were looking at any moment.

In another ingenious methodological development, Senders created a vision sampling device. The video below illustrates how it worked – a mechanical visor rose and fell in front of the driver’s eyes.

Dr. Senders came up with this idea of sampling while driving through a heavy rainstorm at different speeds, while the speed of the windshield wipers stayed the same. The visor in the video does the same — the rate of viewing can be controlled and the attentional demands of the driving task measured.

For more information, see the CogWorks website.

I’ve already covered these techniques in my classes as they are great demonstrations of creativity in research methods. If one has a well defined purpose and goal, a tool can often be created from surprising materials. Another example I often cite is the actual picture of Thorndike’s puzzle box — a splintered and rickety contraption that bears little resemblance to the finely drawn illustrations in intro psychology textbooks.

Tabs, tabs, and more tabs…

This post on Smashing Magazine about vertical navigation had me thinking about the book Anne and I are writing (manuscript due this Friday; panicking…I’m a 10 on the Wong-Baker scale).  In one of the chapters I discuss tab navigation.  When I was looking for a particularly bad example of the use of tabs I remembered Amazon’s website circa 2000.  Fortunately, the Wayback Machine had preserved the travesty of UI navigation for posterity:

Amazon's homepage in 2000

There is a grand total of 15 options and they are not really in alphabetical order (they seem to be grouped).  Amazon can’t be blamed–we probably didn’t know as much as we know now (I can’t believe it was a decade ago!).  But browsing the Wayback entry for Amazon’s homepage through the years certainly shows evolution and an iterative process to  reach the current Amazon navigation scheme which eschews tabs almost entirely for a cascading, vertical navigation:

Amazon's homepage today (2010)
Amazon's homepage today (2010)

Do you have any examples of particularly good or bad examples of tab navigation?

(post image:

History of Multi-touch Research (Bill Buxton)

BusinessWeek has an article on the veiled threat that Apple has made to competitors regarding multi-touch technology.  But the interesting part was a link to a whitepaper written by Bill Buxton.  It’s a great historical overview/crash course of touch and multi-touch research that preceeded Apple’s work back almost 30 years.

Multi-touch technologies have a long history. To put it in perspective, the original work undertaken by my team was done in 1984, the same year that the first Macintosh computer was released, and we were not the first. Furthermore, there was a significant body of prior art on which multi-touch was built.

1960′s Human Factors : The Titan II Missiles

I went on a trip to Tucson over the holidays and toured the last Titan II missile silo. A brief history: from 1963-1982 these missiles were part of the cold war “peace through deterrance” and “assured mutual destruction.” In essence, they provided one reason not to attack the US: even were we destroyed, these missiles would still launch to destroy the Soviet Union.

Politics aside, the control room and interfaces for these missiles were fascinating from a human factors perspective. Gauges, buttons, and rotary inputs reside where we now would expect screens and keyboards. I reflected on this while there: though you need a button for each function, at least the interface never changes.

I snapped the picture below as an example of users improving a system. It appears they are trying to reduce their memory demands by listing on labels the upper and lower boundaries of these controls. It reminded me of the draft beer handles added to the levers in a nuclear power plant (as discussed by Don Norman in “The Design of Everyday Things.“)

A little more history: The Titan sites do not have a perfect safety record. With 54 sites operating for almost 40 years, there were 4 recorded accidents, all where lives were lost and one early fire where 53 people died. Fortunately, none of these accidents resulted in a nuclear explosion, not even in one where the nuclear piece of the missile was blown out of the silo. This site provides a list and engineering analysis of the accidents, and I would be interested in a human factors analysis.

In the accident that ejected the nuclear warhead, the commonly reported story says the explosion occurred when the missile was being serviced and a repairman dropped a heavy tool on the fuel tank. This implies the explosion was instant, however it actually occurred over 8 hours later, as the fuel exited the breech. The best description I could find comes from a newspaper, the Arkansas Leader:

The missile was housed in a silo within a silo that consisted of eight levels. Maintenance crews were working on level two when the accident happened. Attached to the hydraulic standing platforms was a rubberized boot that flipped over between the missile and the platform to prevent anything from falling through if dropped.

The day missile 374-7 exploded, the boot didn’t keep the socket from falling. At 6:30 p.m., maintenance crews entered the silo to begin work after being delayed due to various unrelated equipment malfunctions. The eight- and three-quarter-pound socket fell, hit the standing platform and bounced toward the missile.

The boot had become too pliable through the years, and the socket fell 70 feet down the silo, hit the thrust mount and bounced into the side of the stage one fuel tank. The 100,000-gallon fuel tank emptied into the bottom of the silo. The fuels interacted and generated heat, which in turn increased the pressure on the tanks. At 8 p.m., the wing made the decision to evacuate the control center.

“When we did that, we had no readings and no way of telling what was going on out there,” Gray said. “We lost all readings,” Gray added.

Many attempts were made to get into the control center to see the readings, according to Gray. At 3 a.m., two people, Living-ston and Sgt. Jack Kennedy, made it into the complex. “When they made it in and had to back out because the fuel was so concentrated they couldn’t see, there was some controversy on who told them to turn on exhaust fan 105,” Gray said.

What that did, according to Gray, was pull the heavy concentration of fuel into the equipment area with all the electrical pumps.

“And automatically, boom!” Gray said. “The fire flashed back into the silo, which already had tremendous heat in there, and when the fire flashed back, the stage one oxidizer tank that was already very, very high in pressure, erupted.”

Within one hour of the accident, Gray found the nuclear warhead intact. “It was cracked, but it pegged out on the radio-activity scanner,” Gray said.

Lessons learned from this accident brought about security improvements near nuclear weapons. Security measures to prevent accidents include: all workers wearing a belt with lanyards to attach tools to, a cloth on the platform to reduce the chance of tools bouncing off the platform if they do fall and a renovation of the platforms.

One of our tour guides had actually been stationed at the silo. He was a great guide and a living piece of history. Consistent with what you might expect, he said the hardest times to keep the missile running and protected were the down times, hours of vigilance and inactivity.

Last, I also photographed some of the operation manuals at the museum. Apologies for the fuzziness of these pictures, and I’ll re-type the best bits:

7. Key Run Up procedure, if required. (figure 3-26C)….Performed

Reference SACR 100-24, Volume VI to determine if key run up is required.


Step 8 can only be performed when SYNC indicator is lighted in NORM modes or TRACK/TRSHD indicators are lighted in SPCL modes.


Observe printout on teleprinter. Printout is continuous series of characters RY’s or 64’s if transmitter site is transmitting idle message, or normal message traffic.

9. DEMODULATOR CONTROL PRINT MODE thumbwheel switch …Set as directed


*PVD must be continuously monitored visually or aurally.

*The PVD may be monitored by either a team in the silo or a crew member in the control center utilizing the wire type maintenance net.

For entry into launch duct level one, the PFC will be positioned outside of the opened level two launch duct access door, with sufficient probes to reach in the launch duct unless the PVD is required on level one of the launch duct for a sniff check.

Generally, I notice a large number of if/then/or/only types of commands.

I have only one last thing to say: the fact that Tucson, AZ, Damascus, AK and Wichita, KS are still around is a testament to the power of training and practice over our human frailties.

50th Anniversary of the Eames Lounge Chair

The chair has three upholstered pieces, each attached to a curved plywood shell. The larger one is the seat; the smaller two are back supports. All three are strategically angled to maximize your comfort. Charles and Ray Eames, the husband-and-wife design team behind the chair, had a remarkable understanding of ergonomic principles long before these were developed into a science in the 1970s.

[washington post]