Inner speech: who am I talking to inside my head?

I talk to myself a lot. I'm doing that now.

I don't really know what I'm going to say in this blog post until a voice speaks inside my head. It seems to speak simultaneously with both my thinking and my typing — inner speech, thought, and communication all happening together in some mysterious fashion.

This feels normal to me. And according to an article in this week's issue of New Scientist, "LIfe in the Chatter Box," most people do the same thing. Here's how the article starts out:

Our inner speech turns out to shape our thoughts and decisions in more ways than you might have imagined

IT CAN happen anywhere. I can be driving, walking by the river or sitting quietly in front of a blank screen. Sometimes suddenly, sometimes gradually and imperceptibly, I become conscious of words that no one else can hear, telling me things, guiding me, evaluating my actions. I am doing something perfectly ordinary – I am thinking– and it takes the form of a voice in my head.

If you ask people to reflect on their own stream of consciousness, they often describe experiences like this. Usually termed inner speech, it is also referred to as the inner voice, internal monologue or dialogue, or verbal thought. But although philosophers have long been interested in the relationship between language and thought, many believed that inner speech lay outside the realms of science.

That is now changing, with new experimental designs for encouraging it, interfering with it and neuroimaging it. We are beginning to understand how the experience is created in the brain; its subjective qualities – essentially, what the words "sound" like; and its role in processes such as self-control and self-awareness. The voice in our head is finally revealing its secrets, and it is just as powerful as you might have imagined.

Fascinating.

I looked around the Hearing the Voice web site referenced in the article, but came away disappointed. Mostly the project seems to be focused on inner voices related to schizophrenia and other mental illnesses.

Yet the author, Charles Fernyhough (director of Hearing the Voice), does a good job in his article of discussing the pros and cons of inner speech for those of us who seem to be mentally OK, more or less. I'd hoped to find more on the web site along these lines:

Quite how much our inner and outer speech overlap remains a matter of debate. According to one view, inner speech is just external speech without articulation: the brain plans an utterance, but stops short of kicking our muscles into action. If that is the case, our internal voice should resonate with the same qualities of tone, timbre and accent as our ordinary external speech.

There are some hints that this may be the case. In their lab at the University of Nottingham, UK, psychologists Ruth Filik and Emma Barber recently asked participants to read limericks silently in their heads. One was: There was a young runner from Bath, Who stumbled and fell on the path; She didn't get picked, As the coach was quite strict, So he gave the position to Kath.

The other limerick read: There was an old lady from Bath, Who waved to her son down the path; He opened the gates, And bumped into his mates, Who were Gerry, and Simon, and Garth.

Importantly, some of the participants had northern English accents, with short vowels (pronouncing "Bath" to rhyme with "Kath"), while the others had the long vowels of a southern accent ("Bath" rhyming with "Garth"). By tracking the volunteers' eye-movements, the researchers showed that reading was disrupted when the final word of the limerick did not rhyme in that volunteer's accent – when a southerner read "Bath" then "Kath", for instance.

Although this study suggests that inner speech does indeed have an accent – and presumably other qualities of our spoken voice – one concern is that the inner speech we produce when reading is not necessarily the same thing as our everyday, spontaneous inner speech, which means that more naturalistic studies are needed.

So much for the subjective qualities of inner speech. What, if anything, does it actually do? Vygotsky proposed that words in inner speech function as psychological tools that transform the task in question, just as the use of a screwdriver transforms the task of assembling a shed. Putting our thoughts into words gives them a more tangible form which makes them easier to use. It may also be that verbal thought can allow communication between other cognitive systems, effectively providing a common language for the brain.

One of Vygotsky's most enticing predictions was that private and inner speech give us a way of taking control of our own behaviour, by using words to direct our actions. While driving up to a roundabout in busy traffic, for example, I'll still tell myself, "Give way to the right", especially if I've just been driving overseas. Knocking out the systems responsible for inner speech should therefore impede our performance on certain tasks that require planning and control, offering a powerful test of the hypothesis.

For many years I was an avid mantra meditator. Meaning, I repeated a mantra both during an hour or two of morning meditation, and also during the rest of the day as much as I could. 

The basic underlying hypothesis, though not exactly expressed as such, was that speaking less to myself with my inner voice was better than speaking more to myself — the whole "monkey mind" thing. However, experiments have shown that inner speech enables us to do some things better.

Not surprising, really.

Such experiments typically require participants to repeat a word to themselves out loud to suppress their verbal thoughts while they perform a task (a technique known as articulatory suppression). Using this set-up, Jane Lidstone, one of my colleagues at Durham University, looked at the performance of children aged 7 to 10 on a planning task known as the Tower of London, which involves moving coloured balls around between three sticks of differing lengths in order to match a given pattern.

Lidstone found that children performed worse if they had to repeat a word out loud, compared with trials in which they instead tapped repetitively with one of their feet. Similar findings have emerged from studies with adults. Alexa Tullett and Michael Inzlicht of the University of Toronto in Canada gave student participants aclassic test of control known as the Go/No-Go task, which required them to press a button the moment they saw a yellow square pop up on the screen, but to remain still when they saw a purple square. It is a considerable test of impulse control, and, as predicted, the students were less accurate during articulatory suppression, compared with when they were doing a spatial task.

Although experiments like these seem artificial, they allow researchers the kind of control over conditions that good science demands to test something like self-control.

So we know that inner speech has a role in regulating behaviour, but could it also have a role in motivating it? The research on children's private speech (Vygotsky's precursor of inner speech, remember) shows that it frequently has an emotional or motivational flavour. Athletes often give themselves pep talks before, during and after performances. In our study of the quality of inner speech, McCarthy-Jones and I found that two-thirds of students reported using internal speech that either evaluated their behaviour or served to motivate it.

Inner speech may even help us to become aware of who we are as individuals. Some philosophers have proposed that awareness of inner speech is important for understanding our own mental processes, an aspect of what psychologists call metacognition.

Children typically do not become aware of their own inner speech until around age 4, although it is uncertain whether that reflects their inability to reflect on their own thought processes, or the fact that inner speech is not yet fully internalised by that age.

At Mount Royal University in Calgary, Canada, psychologist Alain Morin has found that people who use inner speech more often show better self-understanding. "Inner speech allows us to verbally analyse our emotions, motives, thoughts and behavioural patterns," he says. "It puts to the forefront of consciousness what would otherwise remain mostly subconscious."

In my current churchless frame of mind I'm considerably less concerned about shutting up my inner speech via a mantra or some other means.

The New Scientist article provided some reasons for being skeptical about the oft-heard meditative claim that a silent mind is a wise mind. Sometimes, it seems. Sometimes not. It all depends.

Inner speech must be good for something, or many things. Otherwise us humans wouldn't have evolved to have it.