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  • ["If you are always trying to be normal, you will never know how amazing you can be." - Maya Angelou]

  • In 1945, two sculptures meant to represent the average man and woman in the United States went on exhibit at the American Museum of Natural History.

  • Based on measurements taken from tens of thousands of young men and women, they were called Norma and Normman.

  • That same year, a contest launched to find a living embodiment of Norma.

  • Normal is often used as a synonym for "typical," "expected," or even "correct."

  • By that logic, most people should fit the description of normal.

  • And yet, not one of almost 4,000 women who participated in the contest matched Norma, the supposedly "normal" woman.

  • This puzzle isn't unique to Norma and Normman, eithertime and time again, so-called normal descriptions of our bodies, minds, and perceptions have turned out to match almost no one.

  • And yet, a lot of the world is constructed around a foundation of normalcy.

  • So what does normal actually meanand should we be relying on it so much?

  • In statistics, a normal distribution describes a set of values that fall along a bell curve.

  • The average, or mean, of all the values is at the very center, and most other values fall within the hump of the bell.

  • These curves can be tall, with most values inside a narrow range, or long and flat, with only a slight bias towards the average.

  • What makes the distribution normal is that it follows this curved shape.

  • Normal doesn't describe a single data point, but a pattern of diversity.

  • Many human traits, like height, follow a normal distribution.

  • Some people are very tall or very short, but most people fall close to the overall average.

  • Outside of statistics, normal often refers to an averagelike the single number pulled from the fattest part of the bell curvethat eliminates all the nuance of the normal distribution.

  • Norma and Norman's proportions came from such averages.

  • Applied to individuals, whether someone is considered normal usually depends on how closely they hew to this average.

  • At best, such definitions of normal fail to capture variation.

  • But oftentimes, our calculations of normal are even more flawed.

  • Take the BMIor Body Mass Index.

  • BMI is a measure of weight relative to height, with different ratios falling into "underweight," "normal weight," "overweight," and "obese" ranges.

  • Generally, only BMIs that correspond to normal weight are considered healthy.

  • But BMI is not always an accurate predictor of health, or even of what's a healthy weight.

  • BMI doesn't take into account body fat percentage, body fat distribution, levels of physical activity, or blood pressure.

  • And yet, those who fall outside the so-called normal range are commonly advised that losing or gaining weight will improve their health.

  • When we apply a standard of normal to all of humanity that's based on data from a non-representative slice,

  • we're not just choosing one point on the distribution, we're choosing it from the wrong distribution.

  • A lot of behavior science research draws from samples that are pretty WEIRDmeaning Western, educated, industrialized, rich, and democratic.

  • These features can skew norms even in research that doesn't have an obvious link to them.

  • Take the famed Muller-Lyer optical illusion: it's normal to think one of the two lines is longer, when they're actually the same length.

  • At least, it is if you're an American undergraduate.

  • A team of anthropologists and psychologists found other demographic groups were much less susceptiblemembers of the San people of the Kalahari weren't susceptible to the illusion at all.

  • When these limited or inaccurate definitions of normal are used to make decisions that impact people's lives, they can do real harm.

  • Historically, such concepts of normal have been hugely influential.

  • The Eugenics Movement of the early 20th century weaponized the concept of normal, using it to justify exclusion, violence, and even extermination of those deemed not normal.

  • To this day, people are often targeted and discriminated against on the basis of disabilities, mental health issues, sexual orientations, gender identities, and other features deemed "not normal."

  • But the reality is that the differences in our bodies, minds, perceptions, and ideas about the world around usin short, diversityis the true normal.

  • And speaking of deeply flawed system of measurement, how much do you know about the dark history of IQ tests? Learn more with this video.

  • Or get the latest on an important debate: Should we get rid of standardized testing?

["If you are always trying to be normal, you will never know how amazing you can be." - Maya Angelou]

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B1 US TED-Ed normal norma distribution bmi normal distribution

What is “normal” and what is “different”? - Yana Buhrer Tavanier

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    大文 posted on 2022/04/17
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