Saturday, 13 September 2014

Inner speech

Have you ever thought about the fact that you are reading this sentence using a voice in your head? That whenever you carry out an action you may be talking to yourself, but silently and within your mind? This voice is referred to as your “inner speech” and exactly how it works has baffled neuroscientists and psychiatrists for many years.

In the 1930s, Lev Vygotsky was the first to try to define the term. He believed that in children inner speech began as external speech (talking out loud) and was initially used as a tool to self-direct or self-regulate behaviour. Eventually, as the child would get older they would become more aware of their surroundings and realise that not everyone speaks out loud all the time, so would begin to internalize this voice... Hence inner speech is produced.

For most of us, your inner voice is generally positive
However, if this is the case, do deaf children experience inner speech? Yes, but in a different way depending on what skills they learn. A child born deaf who learns to only communicate through sign language will think in sign language symbols. However, a child born deaf that is taught to speak the same way you or I do via vocal training will think in a mixture of signs and sounds. It’s interesting to note that deaf children gain their inner voice the same way as a speaking child; deaf children have often been observed in studies signing to themselves the same way a speaking child would talk to themselves, before internalisation of their inner voice.

So what about bilinguals? Interestingly, a study by Dr Francois Grosjean (a bilingual himself) showed that 70% of bilinguals and trilinguals thought in both/all languages they knew. This can be explained however when you realise that language and thinking can be independent of one another. Thoughts can involve non-linguistic concepts, such as a spatial or visuals. Cognitive scientists Steven Pinker and Jerry Fodor even suggest that the language in our heads should really be referred to as “mentalese” – a type of language that depends completely upon the individual, their upbringing, mother tongue and a multitude of other factors. I think in the case of bi/trilinguals it’s also important to remember that they do not need to consciously decide to speak in one language or another. Personally I cannot fluently speak another language, but I know phrases in other languages well enough that I do not need to consciously break it down to understand. For example, when you hear the word “bonjour”, you do not need to consciously recognise that the word is French, and it means hello... It comes naturally – without thinking. The same study also showed that 64% of the bi- and trilinguals dreamed in both/all languages, and the language depended on the subject matter of the dream.

Some people struggle with constantly conflicting inner voices 
Whilst it is commonplace for everyone to hear occasionally negative comments about themselves/their actions in their head, things can take a dark turn when that stream of consciousness becomes permanently critical, or when voices heard are not your own. A permanently negative voice inside your head can be attributed to many mental conditions, including depression. However, in the case of some mental health issues such as bulimia or anorexia, voices/thoughts can be conflicting – some are rational and occasionally positive whilst some are critical and these battle for dominance over each other. Differently, when voices heard inside your head do not belong to you, they are considered to be a hallucination. This simply means a perception you may have that others around you do not share. Whilst these voices are typically associated with mental conditions such as schizophrenia, they can also often be the result of lack of sleep, hunger, drug abuse, or traumatic experiences. Fortunately, as the understanding of what is considered ‘normal’ inner speech develops; the more can be done to help those who experience ‘abnormal’ inner speech.

Mark Scott, from the University of British Columbia, believes he has found a way to explain how inner speech actually works within the brain. The mechanism is based on the idea of corollary discharge – this is a signal within the brain that is also stops us from being able to tickle ourselves. It is extremely complex but along the lines of being a signal that predicts our own movements. In the case of inner speech, corollary discharge works by predicting the sounds we make when we speak out loud and creates an internal copy. It enables us to realise that the voice inside our head is someone else’s. This may then also relate to the mental health issues described above… perhaps those who experience auditory hallucinations have some kind of abnormality involving their corollary discharge?

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