What is “normal” and what is “different”? - Yana Buhrer Tavanier
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, either—
time 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 mean—
and 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 average—
like the single number pulled
from the fattest part of the bell curve—
that 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 BMI— or 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 WEIRD—
meaning 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 susceptible—
members 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 us—
in short, diversity—
is the true normal.
