A Link Between Hearing Voices and Hearing Your Own Voice

It’s the uncommon one that likes listening to their very own voice on a recording. It sounds faux, someway — prefer it belongs to another person.

For neuroscientists, that high quality of otherness is greater than a curiosity. Many mysteries stay concerning the origins of hallucinations, however one speculation means that when folks hear voices, they’re listening to their very own ideas disguised as one other individual’s by a quirk of the mind.

Scientists want to perceive what elements of the mind permit us to acknowledge ourselves talking, however learning this utilizing recordings of individuals’s personal voices has proved difficult. Once we discuss, we not solely hear our voice with our ears, however on some stage we really feel it because the sound vibrations journey by means of the bones of the cranium.

A examine revealed Wednesday within the journal Royal Society Open Science tried a workaround. A staff of researchers investigated whether or not folks may extra precisely acknowledge their voices in the event that they wore bone-conduction headphones, which transmit sound by way of vibration. They discovered that sending a recording by means of the facial bones made it simpler for folks to inform their voices other than these of strangers, suggesting that this expertise supplies a greater solution to examine how we will inform once we are talking. That may be a probably vital step in understanding the origins of hallucinated voices.

Recordings of our voices are inclined to sound increased than we count on, mentioned Pavo Orepic, a postdoctoral researcher on the Swiss Federal Institute of Know-how who led the examine. The vibration of the cranium makes your voice sound deeper to your self than to a listener. However even adjusting recordings in order that they sound decrease doesn’t recreate the expertise of listening to your individual voice. In its place, the staff tried utilizing bone-conduction headphones, that are commercially out there and infrequently relaxation on a listener’s cheekbones simply in entrance of the ear.

The staff recorded volunteers saying the syllable “ah” after which blended every recording with different voices to supply sounds that had been made up of 15 p.c of a given individual’s voice, then 30 p.c, and so forth. Then, that they had some topics hearken to a collection of the sounds with bone-conduction headphones, whereas others used regular headphones and one other group tried laptop computer pc audio system. The volunteers indicated whether or not they thought every sound resembled their very own voice.

Individuals with bone-conduction headphones had been extra prone to appropriately establish their very own voices, the staff discovered. When the researchers tried the identical experiment utilizing the voices of topics’ buddies — pairs of buddies had been recruited particularly for the examine — they discovered that the bone-conduction headphones made no distinction in serving to folks establish acquainted voices. It was solely recognizing their very own voices that grew to become simpler, suggesting that the units are recreating a few of what we really feel and listen to as we converse.

That opens a door to understanding how one’s mind takes this sensory info and turns it right into a recognition of 1’s self. In a examine revealed final yr, the group recorded the neural exercise of individuals performing these listening duties and reported the existence of a community of mind areas which can be activated as folks work to establish themselves.

If scientists can perceive how the mind builds the idea of self from sound, Dr. Orepic suggests, then maybe they’ll unpack what’s totally different in individuals who hear voices of their heads that aren’t their very own. Maybe sometime listening to recordings of voices, together with one’s personal, with bone conduction units may assist medical doctors make diagnoses, if the instrument’s efficiency may very well be linked to psychiatric problems.

In truth, the staff has already begun to review how individuals who had parts of their brains eliminated — to deal with drug-resistant epilepsy, for example — carry out on the duty. The extra the mind’s self-recognition community is disturbed by the surgical procedure, the more durable the duty of self-recognition turns into, Dr. Orepic mentioned, referring to findings in a examine that has but to be peer-reviewed.

For one affected person, whose persona modified considerably after her surgical procedure and who was ultimately recognized with borderline persona dysfunction, the check revealed a stunning sample.

“Each time she heard her voice, she thought it was another person,” Dr. Orepic mentioned. “And when she hears another person, she says ‘It’s me.’”