Many of us have a consistent dialogue running in our heads that we use for a variety of mental tasks, such as working memory — reciting phone numbers or new friends’ names — and reading. Despite its important presence in most people’s daily lives, we know surprisingly little about how it works — or how many of us actually have one.  

Everyone knows we can’t read other people’s minds. But as anyone who has tried meditation can tell you, it’s surprisingly difficult to figure out what’s going on even in our own heads. Russell Hurlburt, a psychologist at the University of Nevada, Las Vegas, wants to change that. As a graduate student in 1973, he came up with something called Descriptive Experience Sampling (DES), a way to investigate inner speech. Long before most of us had smart phones all but glued to our bodies, Hurlburt designed a beeper that research subjects wore in their ears and sounded randomly throughout the day. When the beeper went off, the subjects jotted down what was going on in their minds just before.  

According to Hurlburt, it’s so difficult to study inner voices because people have what he calls “presuppositions” about what’s going on in their minds. Respondents will typically describe what they think researchers want to hear rather than their genuine thoughts, he says.

Research from Hurlburt and other scientists — along with plenty of anecdotal evidence — has indicated that some people don’t hear inner speech at all, or at least not according to their definition of it. In a 2010 Brain Research Bulletin study, 7 percent of subjects did not report having an inner voice.  

That doesn’t necessarily mean those people don’t have one, though. It depends on how you characterize the inner voice, says Ethan Kross, a psychologist at the University of Michigan and author of Chatter: The Voice in Our Head, Why It Matters, and How to Harness It. Virtually everyone can hold information, such as a phone number or a set of directions, in their verbal working memory, he says. By that criterion, we probably all have some sort of inner voice.

However, Kross adds, “As you move up the ladder of complexity in terms of the functions an inner voice serves, I think you see more variability in the degree with which people engage in [inner speech].”

Read the full article at Discover.