For much of the 20th century, many doctors and educators believed that postural defects were signs of ill health, writes Belinda Lanks for The Wall Street Journal.

According to these posture experts, slumping shoulders and protruding stomachs could be indicators of many health issues, from deforming scoliosis to deadly tuberculosis.

This opinion led to nude or seminude pictures of students routinely being taken as part of posture exams at many schools around the country.

In her new book Slouch: Posture Panic in Modern America, Beth Linker, a cultural historian at the University of Pennsylvania, attempts to explain the enduring fixation on posture.

She traces the obsession with posture to Charles Darwin’s 1859 “On the Origin of the Species.” Darwin believed — which was later confirmed — that we stood on two feet before we grew brains that were bigger than those of our ape brethren, which was the opposite of the dominant theory at the time.

From there, the posture epidemic spread as many thought that the spine was not holding up to modern industrialized life.

“What is striking about the poor posture epidemic is that it gained legitimacy and public support without evidence of a contagion,” wrote Linker. “The epidemic was thus defined more by lifestyle and individual behavior than germ transmission.”

Read more about the book covering the slouching epidemic at The Wall Street Journal.

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