Normal and Different

Two sculptures that were intended to represent the typical American man and woman went on display at the American Museum of Natural History in 1945. They were given the names Norma and Normman based on measurements taken from tens of thousands of young men and women. A search for Norma's living embodiment began in the same year. Normal is frequently used interchangeably with terms like "typical," "expected," and even "correct.". By that reasoning, the majority of people ought to be considered normal. None of the nearly 4,000 women who entered the competition, however, matched Norma, the ostensibly "normal" woman. This conundrum isn't just a problem for Norma and Normman either—normal explanations of our bodies, minds, and perceptions have repeatedly been found to fit almost no one. Nevertheless, a large portion of the world's infrastructure is built on a normalcy-based foundation. In statistics, a normal distribution refers to a set of values that fall along a bell curve.

So what does normal actually mean— and should we be relying on it so much? The majority of the other values fall within the bell's hump, which is where the average or mean of all the values is located. These curves can be long and flat with only a slight tilt toward the average, or they can be tall with the majority of values falling within a small range. The distribution is normal because it has this curved shape. Normal describes a pattern of diversity rather than a single data point. Many human characteristics, including height, have a normal distribution. Although some people are very tall or very short, the majority of people are in the middle. Outside of the field of statistics, the term "normal" is frequently used to describe an average, such as the one number taken from the fattest portion of the bell curve, which removes all the complexity of the normal distribution. These averages served as the basis for Norma and Norman's proportions. How closely an individual deviates from this average typically determines whether they are regarded as normal. Such definitions of normal, at best, fall short of capturing variation.

However, we frequently make even more inaccurate assumptions about what is normal. BMI, or body mass index, is an example. BMI is a ratio of weight to height that categorizes people as "underweight," "normal weight," "overweight," or "obese.". The only BMIs that are typically regarded as healthy are those that correspond to normal weight. However, BMI is not always a reliable indicator of one's health or even of what constitutes a healthy weight. Body fat percentage, body fat distribution, levels of physical activity, or blood pressure are not taken into account by BMI. Nevertheless, people who are outside the so-called normal range frequently receive the advice that losing or gaining weight will benefit their health. In addition to picking one point on the distribution, we are also picking it from the incorrect distribution when we apply a standard of normal to the entire human race that is based on data from an unrepresentative slice. A lot of behavior science research uses samples that are fairly WEIRD, or Western, educated, industrialized, rich, and democratic. Even in studies without a clear connection to them, these characteristics can distort norms.

Take the well-known Muller-Lyer optical illusion, where one of the two lines appears to be longer than it actually is. It is if you're an undergraduate in the United States, at least. The San people of the Kalahari were not at all susceptible to the illusion, according to a group of anthropologists and psychologists who studied other demographic groups who were much less susceptible. These constrained or unreliable definitions of normal can cause serious harm when they are applied to decisions that have an impact on people's lives. These notions of normality have historically had a significant impact. Early in the 20th century, the Eugenics Movement weaponized the idea of normal, using it to support the exclusion, violence, and even extermination of those who were deemed to be abnormal. Even now, those with disabilities, mental health conditions, sexual orientations, gender identities, and other characteristics deemed "not normal" are frequently the targets of discrimination.

The truth, however, is that diversity—a term used to describe the variations in our bodies, minds, perceptions, and ideas about the world around us—is the true normal.