Talking to ourselves in our heads fundamentally the same as speaking our thoughts out loud. But new research findings may have implications for understanding why people with mental illnesses such as schizophrenia hear voices.

We all talk to ourselves one and another way by processing our thought and even during talking. But this could lead us to identify the mental illness and problems suffered by a person like schizophrenic etc. Normally talking to yourself is fundamentally the same as talking our thought aloud. When we talk then the thing that we want to convey comes first in our brain and that message is copied in our brain called efference-copy. The name efference is given from reference, so essentially this efference-copy is sent to the brain area that process sound to predict what sound will be there. This makes brain to differentiate between what is our thought and others.   

 A study conducted by UNSW Sydney scientist and study first author Associate Professor Thomas Whitford says it has long been thought that these auditory-verbal hallucinations arise from abnormalities in inner speech — our silent internal dialogue.

We speak lot to self. But to what extent does the brain distinguish between inner speech and the sounds we produce when we speak out loud?

“This study provides the tools for investigating this once untestable assumption,” says Associate Professor Whitford, of the UNSW School of Psychology. As stated earlier about the efference-copy Whitford says “The efference-copy dampens the brain’s response to self-generated vocalizations, giving less mental resources to these sounds, because they are so predictable”.

“This is why we can’t tickle ourselves. When I rub the sole of my foot, my brain predicts the sensation I will feel and doesn’t respond strongly to it. But if someone else rubs my sole unexpectedly, the exact same sensation will be unpredicted. The brain’s response will be much larger and creates a ticklish feeling.”

The study was published in the journal eLife, basically to determine whether inner speech — an internal mental process — elicits a similar efference-copy as the one associated with the production of spoken words.

Researcher team using electroencephalography(EEG) measures the purely mental action of inner speech. There study on the 42 normal and healthy participant measure the brain activity triggering by interfering the imagined sound to the actual sound. They found that the sound they imagined and vocalized were marking less active brain on compared with the sound outside. This clearly shows our thought is enough to change the way our brain perceives the sound.

“By providing a way to directly and precisely measure the effect of inner speech on the brain, this research opens the door to understanding how inner speech might be different in people with psychotic illnesses such as schizophrenia,” says Associate Professor Whitford.

“We all hear voices in our heads. Perhaps the problem arises when our brain is unable to tell that we are the ones producing them.”

Source: Provided by University of New South Wales.Note: containt is edited for style and length.