One of the main characteristics schizophrenics exhibit is the ability to hear voices in their head. Researchers from Yale University employed a novel method to study this phenomenon. They observed psychics and others who hear voices but are not diagnosed with a mental illness.

The study published Wednesday in the journal Schizophrenia Bulletin found that the voices reported by both groups were similar in a few ways but also very different in others.

“We have known for some time that people in the general population can have the experience of hearing voices—sometimes frequently—without the need for psychiatric intervention,” Albert Powers, a psychiatry fellow and lead author of the study, said in a statement.

At least one in 25 people say they hear voices at any given time with up to 40 percent saying that they’ve heard voices at least once in their lifetime. But most of these people are not diagnosed with any mental disorder. Researchers said they had a tough time sorting these people from those with illnesses like schizophrenia in which the patient experiences psychosis.

Scientists studied a group of psychics who claimed that heard voices in their head on a daily basis. The group was first put through tests administered by forensic psychiatrists to make sure that their claim was true. Both the psychics and people with psychosis fared the same in the test meant to weed out those who lied about hearing voices.

Researchers said that one major difference between the two groups was psychics mostly heard positive messages whereas patients were likely to report negative experiences.

“These individuals [psychics] have a much higher degree of control over the voices. They also have a greater willingness to engage with and view the voices as positive or neutral to their lives,” Philip Corlett, assistant professor of psychiatry and senior author on the paper, said in the statement. “We predict this population will teach us a lot about the neurobiology, cognitive psychology and eventually treatment of distressing voices.”

Corlett defended their unusual approach saying very little progress had been made in the past 50 years in understanding psychosis. “The research may be unusual, but big, intractable problems require creative and sometimes unorthodox solutions,” he added.