When the brain speaks without our permission

Have you ever experienced music crawling its way into your head and sticking there for a few hours, sometimes half a day? One particular tune follows you around while you go on with your daily life. It’s usually harmless, but we don’t call it an earworm without a reason: this little beast can be really hard to shake off.¹

I’d like you to think about something next time you get an earworm: how come your brain is reproducing music on repeat without your conscious intent for it, and why your simple wish for it to stop isn’t enough.

Hearing voices and having an earworm are entirely different experiences.

Voices or auditory hallucinations may address you, comment on what you are doing, or interrupt a conversation. Some voices are comforting; others are frightening or exhausting. They may seem to come from outside the head or from within it.²

But where are they coming from?

A 2008 study by Iris Sommer and colleagues at UMC Utrecht offered a fresh insight for looking at this question. They scanned the brain activity of 24 participants with psychotic disorders, when the voices appeared and when participants willingly generated inaudible words (controlled internal reproduction of language).

Brain imaging during conscious inner speaking showed an anticipated picture: along with other structures, the language area of the left hemisphere was activated. The area is called Broca’s, and it’s responsible for generating language when we talk to ourselves, revisit sentences in our mind, or converse. It works within a wider network that, in most right-handed people, is heavily tied to the left hemisphere. This is why we often refer to the left hemisphere as “dominant” – dominant for language.^3,4

So when the 24 right-handed people in the Utrecht study generated words, Broca’s area got lit up. However, when the same people heard voices, the pattern shifted: activity was predominantly placed in the right-hemisphere counterpart of Broca’s area. The dominant language-producing area itself wasn’t significantly active.³

The question the Utrecht article raised can be best summarized as:
could activity in the non-dominant hemisphere produce speech that is experienced by our brain’s auditory centres as external?

The American psychologist Julian Jaynes asked this question long before anyone could watch the brain while it heard voices. He presented his idea publicly in 1969, and in 1976 he published it as a book: The Origin of Consciousness in the Breakdown of the Bicameral Mind (opens in a new tab).⁵

To follow Jaynes, it helps to know what he meant by consciousness. He did not mean seeing, hearing or reacting. He didn’t even mean thinking, since much of our thinking goes on without it. For Jaynes, consciousness is the inner space where you can see yourself in the story of your life. It is where you replay yesterday’s argument, picture tomorrow’s meeting and ask yourself what to do. He believed that nobody is born with this space. We learn it through language.

His boldest claim was that this inner space is only about three thousand years old. Before that, he argued, the human mind worked in two parts, like a parliament with two chambers. This is what “bicameral” means. Jaynes described it as “an executive part called a god, and a follower part called a man”. When a person faced something new or stressful, they did not weigh their options. They heard a voice telling them what to do. That voice did not feel like their own. They heard it as the voice of a god, a king or a dead ancestor.

He found traces of this mind in early literature, above all in Homer’s Iliad. There, it is a god who grabs Achilles by his hair to stop him from striking Agamemnon. Gods lead armies into battle, start quarrels and console the heroes in their grief. “The characters of the Iliad do not sit down and think out what to do,” Jaynes wrote. He did not read these gods as poetic decoration. He believed they were what people actually heard. For these people, to hear was to obey. Even the English word obey comes from the Latin ob-audire, “to hear facing someone”.

Then Jaynes asked where in the brain such voices could come from. In most people, language depends on the left hemisphere. The matching areas on the right side seemed to do very little, and surgeons could remove large parts of them without obvious loss. Jaynes suggested that these areas once had a job of their own: “The language of men was involved with only one hemisphere in order to leave the other free for the language of gods.” In his model, the right hemisphere stored up a lifetime of warnings and advice, and turned it into guidance for new situations. That guidance crossed to the left side through the anterior commissure, a thin bundle of fibres between the two temporal lobes. The left side heard it as a voice.

His strongest evidence came from the operating room. In Montreal, the neurosurgeon Wilder Penfield operated on people with epilepsy while they were awake. Before removing damaged tissue, he touched points on the surface of their brain with a gentle electric current. Most of these points were on the right temporal lobe, and some patients began to hear voices. A fourteen-year-old girl cried out: “Oh, everybody is shouting at me again, make them stop!” Jaynes noticed that the patients did not feel these voices as their own. The voices acted on them, much as he believed the gods once acted on people.^6,5

According to Jaynes, the bicameral mind broke down between about 1200 and 1000 BC. Writing was one cause. Once a god’s commands were written down, people no longer had to hear them. Wars, natural disasters and mass migrations were the other obvious cause – they threw people into situations voices had no answers for. Meeting strangers who spoke and acted differently made people wonder what was going on inside others, and then inside themselves. Slowly, the voices fell silent, and people had to learn to decide for themselves. That learned inner space, he argued, is consciousness.

Jaynes believed the old capacity never fully disappeared. He saw prayer, oracles and prophets as attempts to hear the gods again. He also thought that voices heard today may travel the old route through the right hemisphere. In 1990, he suggested a way to test this: scan the brains of people at the moment they hear voices. The Utrecht study, eighteen years later, did just that.⁵

In 2012, Kelly Diederen, Iris Sommer and colleagues scanned 21 people with psychosis and 21 people who heard voices but had no psychiatric diagnosis. The voices activated a similar network of brain areas in people with and without psychosis, and the scans showed no significant differences between them.⁷

Kirstin Daalman, from Sommer’s team in Utrecht, compared the voices themselves in more than two hundred people who heard them at least once a month. The voices of people with and without psychosis were equally loud, and came from inside or outside the head equally often. The difference lay in what the voices said, how often they came and how much control people had over them. In people with psychosis, the voices more often said negative things.⁸

How people relate to their voices may depend on where they live. The anthropologist Tanya Luhrmann and her colleagues interviewed people with psychosis who heard voices in the USA, India and Ghana. The Americans more often used diagnostic terms for their voices and described violent commands. In India and Ghana, people more often described rich relationships with their voices.⁹

I have no study to back up my further claim, but coming from Ukraine, I can identify the public regard for voice-hearers mostly as “mad geniuses”, who can connect multiple pieces of a world-order puzzle on one canvas, recite poems verbatim, and compose brilliant works they may later burn to ashes. This view, of course, began to change with the doctrine of evidence-based medicine and its influence on new generations.

I still hold a strong belief that the way society perceives and regards voices has a significant imprint on voice-hearers. And what, if not our relationship to a subject, shapes the way it comes across to us?