John E. Karlin, Father of Usability

5 minute read

Usability Matters As you might be aware now, I am keenly interested in Human Factors. Yet, even I admit I didn't know who John E. Karlin was until I read this 2013 article about him in the New York Times. Who is John Karlin? He is widely considered to be the father of human factors engineering.

Mr. Karlin was born in South Africa. After moving to the United States, he worked at the famous Bell Labs from 1945 until his retirement in 1977. According to the New York Times article, "He was a quiet, unassuming mathematical psychologist, electrical engineer, and professional violinist."

He developed a new approach to technology design, surprising in its simplicity and surprising that no one had ever thought about it before. He placed the human experience in first priority when designing human-technology interactions. In fact, he was responsible for developing many of the human-technology interactions that we take for granted today. This included the placement of the numbers on the dial paid on telephones, as well as the length of the telephone cords. He also analyzed how to best arrange the numbers on a number key pad used on later telephones. He even considered the best shape for the keypads. Look at the number keypad on your keyboard. It was his design.

"Technology must be trained by humans, not the other way around"

He took the approach that it wasn't people who needed to be trained but the technology people used needed to conform to human behaviour. As he saw it, humans had to conform to a new technology but he saw that technology needed to conform to humans. This concept became the basis of Human Factors Engineering.

The failed technology landscape - "yes, but can your grandmother use it?"

Consumer technology is littered with hundreds of products that humans are expected to use. The most reviled is, of course, the old VCR player - if anyone still remembers these horrid devices. Most people could insert a VCR tape into the slot and start playing it, but when it came to programming the device to record a program or other non-standard tasks, forget it. Even today, most remote controls for TVs and DVD players contain a bewildering number of buttons and options.

Yet consider the telephone (before they too became programming devices). They were so simple to use that even an elderly grandmother with barely any sight could use this device to call their doctor, children. This was the genius of John E. Karlin.

He considered a device as needing training not the user. What training can you give to an elderly grandmother? She knows the phone number of her child. She sees the dial. All she needs to do is turn on the device (pick up the handset), wait for a dial tone, put her index finger in the appropriate hole corresponding to the first digit and turn the dial clockwise. Then she repeats the number selection for the remaining digits in the correct order. Utterly simple, yet hiding incredibly complex technology.

The question is what does the device need to do in order for a human to use it, not how can we train a user to use the device.

Behind the telephone is an enormous complexity. Yet access to this complexity requires no more than memorizing a series of numbers and performing really simple steps to connect with another phone elsewhere in the world! For Karlin, even these actions needed a rethink. How should the dial be trained so that technology does not get in the way? His solution was not to hide the numbers while dialing by putting them outside the ring.

The Dial Pad

Later, with the development of the Dial Pad, Karlin used the same analysis for this innovation. How should the Dial Pad be trained to be used by a human? Look at your digital telephone and therein lies the answer. After observing users interacting with various iterations of the Dial Pad, he decided that users made less mistakes if the lowest digits were arranged on the top row starting with "1" at the top right hand corner to increasingly higher digits on subsequent rows below. The 0 (zero) was placed on the lowest row.

This reflected another basic principle of human-machine interaction - the mind considers the top left hand corner to be the most important location in any device. It is where our minds naturally first considers when looking at a device and pondering how to use it. Curiously, computer keyboards have reversed this arrangement so that the lowest numbers are on the bottom row with the highest number on top. This probably reflects the longstanding system used in adding machines.

But what is Human Factors?

What is this science/art that John Karlin helped found? Human Factors is a "branch of industrial psychology that combines experimentation, engineering and product design". Human Factors focuses on what a user is "mentally capable" of actually doing with a specific technology. It then seeks to design and improve the technology so that the user has little or no "cognitive dissonance" between what he or she seeks to do with the technology and what it is actually capable of doing. It is, therefore, the cognitive counterpart to the physical study of Ergonomics. It focuses on what the mind thinks in a given situation and with a given technology rather than what a typical human is physically capable of doing in a giving situation and with a given technology.

*“Human-factors studies are different from market research and other kinds of studies in that we observe people’s behavior and record it, systematically and without bias,” Mr. Israelski said. “The hallmark of human-factors studies is they involve the actual observation of people doing things.” *

John E. Karlin founded a systematic and rigorous study of the observation of human behavour to understand the how users think and make decisions on the use of a given technology in a given environment. He placed the responsibility for training on the technology not the user - the user is what he or she is. It is the technology that must conform to the user, not the other way around.  

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