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People (wrongly) attribute personality traits to body shapes, study finds

The findings suggest that “people infer personality traits from body shapes in systematic and reliable ways,” researchers say, even though those inferences have no basis in fact.

When we meet people for the first time, we tend to subconsciously make instant assumptions about their personality — such as whether they are lazy, self-confident, quarrelsome or dependable — based, at least partly, on their body shape, according to a study published recently in the journal Psychological Science.

The findings aren’t entirely unexpected. Previous research has already shown that people form first impressions of others’ personalities, including their trustworthiness and emotional stability, based solely (and bogusly) on the shape of their faces. Studies have also demonstrated that we tend to label obese people as being lazy and incompetent based only on the size of their body.

This new study, however, looked at the role that more nuanced aspects of body shape — beyond weight — play in our stereotyping of people’s personalities.

“Our research shows that people infer a wide range of personality traits just by looking at the physical features of a particular body,” said Ying Hu, the study’s lead author and a psychologist at the University of Texas at Dallas, in a released statement.

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The start of the stereotypes

Needless to say, this study’s finding is discouraging, for it underscores the pervasiveness of a long-debunked psychological theory about body shape and personality that was first proposed by Dr. William Sheldon, an American psychologist and physician back in 1940.

Sheldon believed that the human shape could be categorized into three “somatotypes,” which could be used to predict a person’s temperament, moral character and mental abilities. In his thinking, mesomorphs (broad-shouldered, well-muscled, straight-backed) were energetic, courageous and desirable. Ectomorphs (thin, usually tall, lightly muscled) were neurotic, introverted and intellectual. Endomorphs (round-shaped, usually short, “soft”-muscled) were lazy, dependent and undesirable.

It took a couple of decades, but Sheldon’s somatotypes were eventually — and thoroughly — discredited — but, unfortunately, not before they had taken hold of the public’s imagination. The categories still play a role in pop psychology, and are referenced by people advising on all sorts of things, including how to dress, how to eat and how to choose a sports activity.

How the study was done

For their study, Hu and her colleagues used laser scans of human bodies to create 140 realistic, three-dimensional body models. Half were female, half were male.

The researchers then showed these models (each from two different angles) on a computer screen to 76 undergraduates students. The screen also contained 30 words representative of all dimensions of the Big Five personality traits, which are commonly used in psychology research to assess personality. The students were asked to identify the traits they thought were most applicable to each body model.

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The study found that people do indeed infer a wide range of personality traits from body shapes.

Here are some of the key findings:

  • In general, the study’s participants linked the heavier bodies with negative traits, such as carelessness, disorganization and laziness.
  • Slimmer bodies were associated with positive traits, such as self-discipline, enthusiasm and carefulness.
  • Body shapes that were either stereotypically feminine (pear-shaped) or masculine (broad-shouldered) were linked with more “active” personality traits, such as quarrelsome, extraversion and irritability.
  • More rectangular male and female body shapes were linked with “passive” personality traits, such as trustworthiness, shyness, dependableness and warmth.

Even small changes in body shape (one shape being slightly heavier than another, for example) affected the study’s participants’ assumptions of what the person would be like. Furthermore, the associations uncovered in the study were so strong that the researchers were able to reliably predict which traits the students would apply to specific combinations of different features of the body shapes.

Resist the impulse

The study comes with several important caveats. Most notably, its participants were young undergraduates attending the same university.

“Although we believe that all humans infer personality traits from body shape, we expect that these inferences will differ substantially across ethnicity, culture, and possibly age,” write Hu and her colleagues.

In addition, the study’s participants were looking at 3-D models of human bodies. If they had encountered the body shapes in the real world — as actual people — they might have linked different personality traits to them.

Still, the findings suggest, say Hu and her colleagues, that “people infer personality traits from body shapes in systematic and reliable ways.”

We should resist the impulse to make those snap inferences, however, as the idea that body shapes are linked to personality traits has absolutely no basis in scientific fact — and can lead to harmful stigmas.

Keep that in mind the next time you meet someone new.

FMI: You’ll find an abstract of the study on the Psychological Science website.