The concept of ‘normality’
Kat Holmes, in her book Mismatch, masterfully addresses the concept of normality, exploring how designers and engineers throughout history have tried to simplify users’ needs to generate a solution valid for everyone (or for the majority).
Within the concept of normality, one figure stands out above the rest: the Belgian Adolph Quetelet. Quetelet was a 19th-century astronomer and mathematician.
On the other hand, Todd Rose, in his book The End of the Average, offers a comprehensive look at Quetelet’s universe. Quetelet aimed to use mathematical methods to understand uncertainty in society. It’s important to highlight the historical context of the time, as Belgium was undergoing a revolution and the population was ravaged by battles, experiencing unstable times.
Quetelet found a valid tool in the Gaussian distribution, the well-known bell curve, through which the probability of an event could be represented. The average, marked by a central vertical line, gave the closest representation of the true nature of the event.
Quetelet began a strenuous effort collecting measurements of different human bodies, not only focusing on basic characteristics such as height or weight but also expanding to include aspects like behavior and morality. He extrapolated all these data to the Gaussian curve and found his ideal human in the average of the curve. In this way, he determined the perfect human face, height, intelligence, and morality.
With this theory, a new concept was born: a model of perfection to which one should conform. Of course, anyone who was not in the average was considered outside of normality.
This theory spread to other sciences, and one formula that many of us are familiar with and is still used today is the body mass index (BMI).
Quetelet’s theory of the average man was not harmless, as it supported dangerous ideas that were already in the minds of some, such as eugenics or the superiority of certain races and social classes.
Let’s pause to examine a couple of examples of the use and consequences of applying the theory of the average man.
The USAF and its pilot shortage
The first fighter planes of the United States Air Force (USAF) were designed to fit an average pilot, as Rose explains. They measured the bodies of thousands of pilots, and based on the average of these data, they designed the flight cockpit instruments. These instruments were fixed to the base of the aircraft, immovable, and could not be adjusted.
During World War II, they discovered that they were running out of pilots due to the high rate of accidents they were suffering, and they were forced to review the cockpit design.
They chose ten of the many human dimensions originally used to design the cockpit and took measurements of four thousand pilots to see how many fit all ten dimensions. The result was zero. The cockpit design was suitable for absolutely no one.
The average dummy
Another example of Quetelet’s studies’ application is in the automotive industry. As is well known, vehicle safety tests are conducted using dummies. Dummies are mannequins that replicate the physical characteristics of a human being and imitate the human body’s reactions to potential vehicle impacts.
For years, the dummies used for safety tests were built based on the average male body type. It was not unknown that women were more likely to be injured in a car accident.
In 2011, it was highlighted that car accidents were a leading public health risk. This led to a series of checks, the results of which yielded chillingly objective data. The safety ratings for the passenger seat plummeted when tests were conducted with a female dummy measuring 1.50m and weighing 49 kilos. Studies revealed that a female driver wearing a seatbelt faced a 47% higher risk of death or serious injury than a male driver.
It wasn’t a problem specific to the occupant’s gender. The average male test dummy measured 1.75m and weighed 78 kilos, and anyone who did not fit those measurements was at a significantly higher risk.
The concept of normality in user experience
As experience designers, we face the constant challenge of creating products and services that are accessible and satisfying for a diverse audience. Inclusion is not just a noble ideal; it’s a practical necessity in a world where individual differences are the rule, not the exception. Ignoring this diversity risks alienating large segments of our audience, limiting the impact and reach of our solutions.
Our responsibility as UX Designers is threefold. First, we must commit to deeply understanding our audiences, including those whose needs have historically been ignored or misunderstood. This involves going beyond assumptions and stereotypes to engage users in the design process, using research and participatory design techniques.
Second, it’s crucial to adopt a flexible and adaptable design approach, allowing for customizations and adjustments to accommodate a wider range of users. This includes considering multiple modes of interaction, display preferences, and accessibility from the outset of the design process.
Finally, but no less importantly, we must be advocates for inclusion within our organizations and communities. We need to challenge existing practices, promote awareness of inclusion, and work to make it a priority in all design projects. Inclusion should not be an add-on or an afterthought; it must be an integral part of our design practice from the start.
As John Maeda says in the foreword to Kat’s book: “Designing for simplicity in the future will be impossible unless we make an effort to understand the underlying complexities of how we design today. If we don’t, we will only create more mismatches. We will create experiences that are simple only for people like us.”
This article is based on the book:
MISMATCH: How Inclusion Shapes Design, Technology, and Society by Kat Holmes.
This is a translation of the following article from our corporate website:
