Which piece of information do you know because of your job or study that would shock people?

Early childhood trauma is visible in teeth. Trauma in this sense is anything that causes a stress response in the body—illness, parental separation, or abuse. Teeth grow at a predictable rate, almost like tree rings. If you bisected a tooth and examined it under a microscope, you'd see rings of growth. Growth is disrupted during times of stress.

The first stress ring we all have on our baby teeth is from birth. Other stressors create further growth disruptions. My former professor, a pioneer in dental anthropology, specialized in analyzing these stress lines. He worked with zoo colleagues who would send him teeth from deceased primates or teeth that had been pulled. Initially, he wouldn’t ask for any additional information.

He and his grad students would then section the teeth, examine them under a microscope, and identify stress lines. Knowing that birth is the first disruption and understanding how fast teeth grow, they could count the days between each disruption to identify when stress occurred. They found that each disruption exactly matched stress events in the primates' lives. Some lines indicated illness, but one particularly interesting case showed a disruption when a primate baby was briefly separated from its mother for health checks. This brief separation caused such a stress response that it became visible in the tooth growth.