Perhaps unsurprisingly, by doing this he was able to show that people who are usually barefoot tend to have thicker calluses.
Interviewee: Dan Lieberman Nobody had actually tested that before, so that’s nice to know.
Firstly, Dan set about trying to determine if people’s calluses do indeed get thicker when they don’t wear shoes.
To do this, he studied the feet of a population of people in Kenya, some of whom never wear shoes, some that wear them infrequently and some that wear them all the time.
By changing how fast the probe vibrated and seeing when people could feel it, he could measure the sensitivity of nerves on their feet called mechanoreceptors.
Interviewee: Dan Lieberman No matter how thick your calluses were, there was no loss of sensory perception, so that people with thick calluses more or less had the same sensory perceptions as people who had thin calluses.
Interviewer: Nick Howe Once he had shown that this was the case, the next question was, do these thicker calluses mean that people feel less through their soles?
To test this, he and his colleagues used a vibrating probe, that could be placed on the soles of people’s feet.
These images allowed him to see the size of people’s calluses.
So, if these ancient humans could go without shoes, why couldn’t I?