How Can We Listen to Human Thoughts?
‘Wait… Can we really do that?’ For a brief moment, you recited the sentence in your thoughts, didn’t you? Well, this edition will cover some mind :P blowing facts on how we are trying to listen to that thought for real.
But thoughts aside for now. Let’s start with real talking! When you say something like “ring dinge ding dinge ding”, how is your friend able to hear that? That process is called vocalization. It is one of the interesting things that you can find in animals and birds. The dynamics of your larynx is a brilliant design of nature that’s a result of millions of years of human evolution.
To make you say, “ring dinge ding dinge ding” there are three parts in the larynx that work together to produce that sound. The lungs provide the necessary air for the vocal folds to vibrate and create the sound signal. Then the signal gets filtered by the resonant physical properties of your vocal tract. When this sound successfully reaches out of your mouth, the vibration travels through the air molecules, and finally, you can be heard out loud. That’s all there to the sounds that are spoken aloud.
Could we hear if someone talks silently?
When we tone it down to whispering or silent speech, it is impossible for a human to hear your voice, unless he or she is capable of reading your lips and decoding what you are saying. But there is a similar and a better way to listen to your silent talk, which is far more accurate than reading your lips or using an electrolarynx. It’s called electromyography or EMG.
With the technique of EMG, one can measure the electric potential of your vocal muscles and process that signals with machine based voice recognition algorithms. Several prototypes using EMG technique have successfully demonstrated the ability to recognise what a person say with just the movements of the muscles. So listening to your unvoiced speech is quite easy – when electrodes are attached to your throat and face.
But does that help in reading someone’s thoughts?
Oh yes! You might think that you don’t move your muscles while you think “ring dinge ding dinge ding” in your mind. The fact is that you actually do move your vocal folds a bit. So if that delicate movement can be detected, your thoughts can be processed to a similar process mentioned above and then to a speech synthesizer to be heard out loud. That subtle movement of your vocal folds and the inner voice you hear when you think or read a book is called as subvocalization.
There’s more to subvocalization and the domains of reading minds of a human, vaguely dubbed as synthetic telepathy. With advancements in neuroimaging, we have already achieved motor control and brain-computer interfaces. By integrating the ability to detect these minute muscle movements and with the help of deep learning algorithms that could process that data, in the foreseeable future, anyone can be wired to one such system and have their thoughts read out aloud.
For the curious — ♫ ring dinge ding dinge ding ♫
The last part about reading one’s subvocalization is really creepy.