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

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1. 0:06In 1945, two sculptures meant to represent the average man and woman
2. 0:11in the United States
3. 0:12went on exhibit at the American Museum of Natural History.
4. 0:17Based on measurements taken from tens of thousands of young men and women,
5. 0:21they were called Norma and Normman.
6. 0:24That same year, a contest launched to find a living embodiment of Norma.
7. 0:29Normal is often used as a synonym for “typical,” “expected,”
8. 0:34or even “correct.”
9. 0:36By that logic, most people should fit the description of normal.
10. 0:39And yet, not one of almost 4,000 women who participated in the contest
11. 0:44matched Norma, the supposedly “normal” woman.
12. 0:48This puzzle isn’t unique to Norma and Normman, either—
13. 0:51time and time again, so-called normal descriptions
14. 0:54of our bodies, minds, and perceptions have turned out to match almost no one.
15. 1:00And yet, a lot of the world is constructed around a foundation of normalcy.
16. 1:04So what does normal actually mean— and should we be relying on it so much?
17. 1:10In statistics, a normal distribution describes a set of values
18. 1:14that fall along a bell curve.
19. 1:16The average, or mean, of all the values is at the very center,
20. 1:20and most other values fall within the hump of the bell.
21. 1:24These curves can be tall, with most values inside a narrow range,
22. 1:28or long and flat, with only a slight bias towards the average.
23. 1:32What makes the distribution normal is that it follows this curved shape.
24. 1:37Normal doesn’t describe a single data point, but a pattern of diversity.
25. 1:42Many human traits, like height, follow a normal distribution.
26. 1:46Some people are very tall or very short,
27. 1:49but most people fall close to the overall average.
28. 1:52Outside of statistics, normal often refers to an average—
29. 1:56like the single number pulled from the fattest part of the bell curve—
30. 2:00that eliminates all the nuance of the normal distribution.
31. 2:04Norma and Norman’s proportions came from such averages.
32. 2:08Applied to individuals, whether someone is considered normal
33. 2:11usually depends on how closely they hew to this average.
34. 2:15At best, such definitions of normal fail to capture variation.
35. 2:19But oftentimes, our calculations of normal are even more flawed.
36. 2:24Take the BMI— or Body Mass Index.
37. 2:28BMI is a measure of weight relative to height,
38. 2:31with different ratios falling into “underweight,”
39. 2:35“normal weight,” “overweight,” and “obese” ranges.
40. 2:39Generally, only BMIs that correspond to normal weight are considered healthy.
41. 2:45But BMI is not always an accurate predictor of health,
42. 2:48or even of what’s a healthy weight.
43. 2:50BMI doesn’t take into account body fat percentage,
44. 2:53body fat distribution, levels of physical activity, or blood pressure.
45. 2:58And yet, those who fall outside the so-called normal range
46. 3:02are commonly advised that losing or gaining weight
47. 3:05will improve their health.
48. 3:07When we apply a standard of normal to all of humanity
49. 3:10that’s based on data from a non-representative slice,
50. 3:14we’re not just choosing one point on the distribution,
51. 3:17we’re choosing it from the wrong distribution.
52. 3:19A lot of behavior science research draws from samples that are pretty WEIRD—
53. 3:24meaning Western, educated, industrialized, rich, and democratic.
54. 3:31These features can skew norms
55. 3:33even in research that doesn’t have an obvious link to them.
56. 3:36Take the famed Muller-Lyer optical illusion:
57. 3:39it’s normal to think one of the two lines is longer,
58. 3:42when they’re actually the same length.
59. 3:44At least, it is if you’re an American undergraduate.
60. 3:47A team of anthropologists and psychologists
61. 3:50found other demographic groups were much less susceptible—
62. 3:53members of the San people of the Kalahari
63. 3:55weren’t susceptible to the illusion at all.
64. 3:58When these limited or inaccurate definitions of normal
65. 4:01are used to make decisions that impact people’s lives,
66. 4:04they can do real harm.
67. 4:06Historically, such concepts of normal have been hugely influential.
68. 4:11The Eugenics Movement of the early 20th century weaponized the concept of normal,
69. 4:16using it to justify exclusion, violence, and even extermination
70. 4:21of those deemed not normal.
71. 4:23To this day, people are often targeted and discriminated against
72. 4:27on the basis of disabilities, mental health issues, sexual orientations,
73. 4:32gender identities, and other features deemed “not normal.”
74. 4:36But the reality is that the differences in our bodies, minds,
75. 4:40perceptions, and ideas about the world around us—
76. 4:43in short, diversity— is the true normal.