As a neuroscientist, one aspect of brain-science that has always intrigued me is the idea that we may never know exactly how another person experiences the world and whether their experiences differ from our own. I know what the red ball (pictured right) looks like to me but how do I know that you’re seeing same thing? In fact, I’ve often wondered what it would be like to see the world through the eyes of someone whose perceptions differ from mine, for example someone with colour or face blindness.

Sadly though, I’ve always ass umed that my own experiences are disappointingly mundane and ‘average’. That was until ‘life guru’ Karl Pilkington taught me otherwise…

A few months ago, during a particularly long experiment, I was passing time listening to old exerts from the Ricky Gervais show when I came across the following dialogue:

Reading from Karl’s diary: “While I sat listening to The Kinks on my iPod, I wondered if everybody thinks in their accent. I know I do.”

Stephen: What’s this? What are you talking about?

Ricky: How do you know you think in your accent? Tell me a typical thought

Karl: I thought “that’s weird innit?” not “that’s weird isn’t it?” and I thought “I actually think in my accent”

Ricky: No, but, when I think I don’t think the sentence as like I’m saying it, it’s just a thought, the thought appears, it’s conceptual and it’s already there. It’s not like I go, “Rick?” “What?” “Just err… looking at that fella over there were you?” “Yeah, I was yeah. Erm, I was think he looked a bit weird” “Oh, so was I”, I don’t think out whole sentences…

Stephen: Is that how your mind works?

Karl: In a way, yeah

Ricky: Brilliant, it’s great, he has to think out whole sentences!

Stephen: That explains a lot!

This sparked my curiosity since, as far back as I can remember I’ve always thought in complete sentences, often to the extent that I have conversations with myself inside my own head – I just assumed that this was a pretty normal thing to do!

So, I decided to do a bit of my own research into this ‘inner monologue’. This research began life (as many eminent and respected studies often do) on Facebook, where I asked a number of friends:

“What is it like to climb inside someone else’s head? – I’m researching for a post on the inner monologue and, although I think in words like I’m narrating my own life, apparently there are people who don’t…what’s it like inside your head? and if you don’t think in complete sentences, how do you think?”

From this question I got some pretty interesting answers – In brief, most people who responded had some kind of inner voice but few regularly thought in complete sentences or engage this voice in conversation. Some interesting answers included:

“I think in pictures like I’m watching a silent film. In order to submit things to memory I have to have visuals as i struggle to remember audio descriptions. So most of my memory is made up of pictures and that’s how my thought processes work!”

“I sometimes imagine a highly adapted version of something I’ve read or watched – featuring me – and tailored to my real life situation of the time. Less actual words, more images, but like I’m an outsider observing myself observe my situation.”

“I think I only think in words when I’m either a) questioning something (“why’s that there?”) or b) making a decision to do something (“cup of tea!”). I often say such things aloud too when I’m alone.”

“I was wondering about my very minimal inner monologue after talking to my husband about it earlier this week. I find it incredible how most people seem to constantly be thinking in words/sentences. It sounds exhausting to me. I think in actions, visualizations, feelings, impulses and only really have a proper inner monologue when reading or writing. I never know internally what I’m about to say out loud (unless I force myself to do so, or if I’m nervous about talking in specific situations). Often my mind seems blank with no thoughts. I find meditation very easy.”

“I have narrated my life for as long as I remember. Sometimes, when something is particularly challenging, I sort of Parkinson interview myself, as if the problem is now in the past, and I’m discussing how I overcame it….I’ve done that since I was a teenager!”

So, it seems like people experience a huge spectrum of inner ruminations – from short sharp assertions “cup of tea!” to long complex “Parkinson style” inner interviews.

But what do scientists actually know about this inner voice? Well, unfortunately it seems that this is one topic that’s been neglected by modern science. However, inspired by the theories of L. S. Vygotsky, modern research has now again picked up the baton and started to delve into the inner workings of the verbal mind.

Where does the inner voice come from?:

Vygotsky believed that inner speech starts to develop in early childhood, evolving from a phenomenon known as ‘private speech’. Many young children talk to themselves while playing – I remember I used to talk to myself, I’d also sometimes have conversations with inanimate objects (perhaps a downside of being an only child?). Vygotsky called this dialogue private speech and suggested that it comes from social dialogues with parents which, in later childhood, becomes internalised as inner speech.

This would imply that inner speech relies on the same biological mechanisms as those used when we speak out loud. Interestingly, we know that inner verbalisation is accompanied by tiny muscular movements in the larynx – it’s as though audible speech is almost produced but is then silenced at the last minute. If anyone’s like me, they may have experienced the phenomenon of externalised inner speech: when I’m deep in internal thought I’ve been known to accidentally say things out loud which should have stayed in my head.

Neuroscientists have also found that an area within the left inferior frontal gyrus, known as Broca’s area, is active when we speak out loud and also during inner speech. Intriguingly, if this region is disrupted using magnetic brain stimulation both outer and inner speech can be altered.

And, to answer Karl’s question….It has been suggested that, assuming inner speech derives from childhood verbalisations, the voice you hear in your head should sound like your own voice – as Karl would say “everybody thinks in their accent”.

Interestingly, studies of limericks suggest that this is indeed the case! Ruth Filik and Emma Barber from the University of Nottingham asked participants to read two limericks silently in their heads, these being:

1) 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.

2) 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.

All participants were native to the UK, some having northern accents and others southern. In the UK there is a strong regional divide in the pronunciation of the words bath and path, with southerners rhyming bath/path with Garth while northerners rhyme bath/path with Kath (this being the correct way to pronounce things). By tracking participants eye movements the researchers were able to tell when they were reading a rhyming or a non-rhyming sentence. From this they found that both groups appeared to read silently in their own regional accent (although this is not always the case).

So, what does inner speech actually do?

Vygotsky thought that inner speech may help people to perform difficult tasks. Thinking a task through in words may make it easier to accomplish – there are definitely a lot of words going through my mind when I’m building Ikea furniture. Actually, a number of studies have found that people tend to perform worse on tasks which require planning (like playing chess) if their inner voice is suppressed while performing the task.

Recent studies have also found that inner speech often has a motivational quality. In fact, one of my friends offered this example of her inner voice: “I tend to ask myself questions and then think through the different answers. Also I cheer-lead myself along- ‘Right, ok, you can do this!’”.

The self reflective tendency of the inner monologue may also allow us to reflect more on who we are as individuals. Indeed, Canadian psychologist Alan Morin suggests that people who use inner speech more often also 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.” This idea is further supported by a study of neuroanatomist Jill Bolte Taylor who reported a lack for self awareness after a stroke which damaged her language system.

But, I doubt my friends who reported the lack of an inner voice suffer from any associated lack of self awareness. Therefore, I’m sure that there are still a number of individual differences which remain unaccounted for in these studies.

The dark side:

Just as your inner voice can be your own personal cheerleader giving you a boost when you’re feeling low, it can also be your worst enemy. Alongside my Facebook friends, I also posed my question to a group of individuals who, like myself, have been or are currently struggling with depression and/or anxiety. I was intrigued to find that, of all 30 responses, only a couple of people reported not having an internal monologue and most said that their inner voice was conversational (like my own). Not just this but most also said that their inner voice was ‘nasty’ and ‘cruel’ repeating phrases such as “you are useless” or “you aren’t good enough”.

There are a number of studies which support this observation, specifically suggesting that depressed older people rely more heavily on negative internalised speech than social communications when constructing their view of reality (giving them a negative outlook on life). Indeed, the backbone of cognitive behavioural therapy (a commonly used tool in the treatment of mental illness) relies on teaching individuals to re-frame or alter negative thought processes like those mentioned above – “I can’t do it” may become “it’s a challenge but I’m capable given enough time”

Researchers are still not sure how the inner monologue, negative thought processes and social isolation interact in the case of depression. It may be that withdrawal from social interaction leads to a greater dependence on internal processes or perhaps disordered negative thoughts breed the need to withdraw from society. Whatever the case, a better understanding of the mechanisms behind our inner critics may help understand and treat those suffering from depressive illnesses.

Researchers from Durham University found that around 60% of people report that their inner speech has the to-and-fro quality of a conversation. So, despite Ricky and Stephen’s surprise, it seems that Karl perhaps isn’t that abnormal after all. With inner speech being such a wide-spread phenomenon and knowing its possible links with mental health, perhaps it’s time scientists paid a bit more attention to the little voice in our heads?

Post by: Sarah Fox