By Effie Eshetu
“Please be quiet, I can’t hear myself think!” This colloquial saying sounds completely logical to most of us. However, to others, upon a little dissection, it may seem semantically dissonant, and even nonsensical. This is because some individuals actually cannot, regardless of how quiet the room is, hear themselves think (Epting, 2020).
The brain is constantly receiving information and stimulated by its environment: the feel of a warm breeze, the smell of coffee as you rush past a café on the way to a lecture, the sound of a dog barking. We are all subject to experience such stimuli, however, variation lies in how our trillions of neural connections process this information. One might for example, hear the high-pitched yelp of a nearby dog, and think to themselves, ‘I bet that was a Chihuahua!” What does look very different from person to person however is how that conclusion is reached. It could be ‘heard’, what the scientist Lev Vygotsky referred to as “innerly speech”. Such processing has been normalised by countless movies and novels, where the protagonist usually narrates their own story in words, in that familiar “internalised form of speaking out loud” (Heardman, 2019). It could also be ‘seen’, where one conjures up an accompanying mental image of the well-known breed. Some also report visualising the text of whatever words they’ve just thought of, ‘dog’, ‘small’, ‘brown’. To many, the two go hand in hand, an inner monologue scripting the imagery in the ‘mind’s eye’.
To yet another subset of the population, however, thoughts are experienced in silence. People have detailed an inner experience of images, text, abstract impressions, feelings and often a patchwork of all of these elements. In one article, a man attempts to elucidate such an inner experience, likening it to what we might experience in a dream: “you kind of know where you are, even when there is nothing to suggest you know where you are. You just have an implanted knowledge” (Bellmund, 2018). Another individual described his reflection on how they replay memories, stating an experience of a “conceptual list of things that occurred rather than a movie reel playing in their mind” (Bellmund, 2018). While difficult to articulate, this somewhat nebulous anecdotal evidence, is of course useful, affording scientists a glimpse into the vast vocabularies of the human experience, and the variety of ways the brain is capable of internalising and processing information (Holohan, 2020).
This raises an interesting question: where are these non-verbal impressions are stored? Recent research on the fundamental principles of thinking points to the importance of an internal navigation system within the brain that guides our thoughts, and the accompanying images. Professor May-Britt Moser, Professor Edvard Moser and Professor John O’Keefe were awarded the 2014 Nobel Prize in Physiology or Medicine for their work on this so called ‘Internal GPS’. They detailed two types of cells that constitute this navigation system: place cells and grid cells. Grid cells are a neuronal cell type located in the entorhinal cortex that fire action potentials when an animal is investigating a new area, allowing the subject to store and build a bank of information on the location, distance and direction. Essentially, these serve the function of helping the brain create a map of its surroundings. Place cells are a type of hippocampal pyramidal neuron and are named as such because they were found to fire action potentials when an animal experimental subject enters a specific location, or ‘place’. Were the animal to re-enter a familiar location on the mentally fashioned ‘grid’, the same place cell will fire as the first time that place was explored (Bellmund, 2018).
First shown in rodents, these cells have also now been shown to exist in humans. The relation here to the matter of our ‘inner experience’ is that these same cells not only allow special navigation but have been shown in a 2016 study to be activated when learning in a more general sense (Bellmund, 2018). The map in this case being a sort of charted “train of thought”; in the same way that a map details a geographical space, in this case, it details a space for thoughts. What does this mean? Well, for example, if you come across a description of a city you’ve never been to, of a streetlamp-lit promenade and the smell of saltwater, you may begin to draw on similar places you’ve experienced in some way before and subconsciously stored in this mental map; facts you may have learnt in a travel blog, a kindred memory of a road-trip to your favourite beach 2017, the abstract bundle of feelings you may get whilst being on holiday. In that moment, you recall these associated ‘areas’ stored somewhere on your mental map and use it to understand the newly encountered information better and potentially then group it in a similar ‘cognitive space’ (Holohan, 2020).
All this to say, the ‘voice’ that so many of us consider to be essential to navigating our way through life, is actually quite dispensable, with many narrating and navigating day to day life using their own unique blend of mental media – experiences and facts and emotions and images – stored, retrieved and constantly added to, narrating their story in their own unique way.
References:
Epting, M. (2020) ‘Some People Don’t Have An Inner Monologue And I Am One Of Them’, Data Driven InverstorTM, March 22. Available at: https://medium.com/datadriveninvestor/some-people-dont-have-an-inner-monologue-and-i-am-one-of-them-1c47a0e8b48a (Accessed 27 August 2018)
Heardman, T.P (2019) ‘Inner speech, self-talk, internal monologue – we unpack the psychology of our thoughts’, Dazed, 28 May. Available at: https://www.dazeddigital.com/science-tech/article/44494/1/living-without-inner-speech-voice-inside-head-psychology-science (Accessed 27 August 2020)
Bellmund, J. (2018) ‘Navigating Our Thoughts: Fundamental Principles of Thinking’, Neuroscience News.com, November 9. Available at: https://neurosciencenews.com/thought-navigation-system-10175/ (Accessed 27 August 2020)
Taylor, S. (2018) ‘The Voice Inside Your Head’, Psychology Today, March 26. Available at: https://www.psychologytoday.com/gb/blog/out-the-darkness/201803/the-voice-inside-your-head (Accessed 27 August 2020)
Holohan, M. (2020) ‘Some people don’t talk to themselves. Are they better off?’, Today, February 2020. Available at: https://www.today.com/health/experts-talk-about-what-it-means-have-inner-monologue-t173490 (Accessed 27 August 2020)
Imperial Bioscience Review 