Why do I hear things that aren't there?

23 June 2014

Question

I'm a music composer and there are times when I am relaxed, just about to go to sleep, and have no distractions in the room, I can bring sounds and voices and music to my ears. The sound is so clear that it is almost having headphones or a person right next to me. The noise is directly in my ears like real sounds and not in the same place as normal thoughts in my head during the day. Why does this happen?

Answer

So now, we attend to the next question which comes from listener Kris Oliver who's been in touch saying, "Why do I hear and see things that aren't there?" So, he's a music composer and at times when he's relaxed or he's just about to go to sleep, he can bring voices or auditory hallucinations into his mind so he can hear things that other people can't hear. He's asking what's going on there. Apparently, this isn't uncommon. So, I spoke to the head of the department of psychiatry at Cambridge University and he said that a recent study that's been published indicates that about 10% - so, 1 in 10 older teenagers will actually experience the same thing, these hallucinations even though they're not actually psychotic. So, they haven't got Schizophrenia but they are experiencing things that other people don't. So, what's going on there?

Martin - So, conscious perception of sound results from the processing of sound waves, either the brain's auditory system, in the same way the conscious perception of colour results from the processing of light waves and particles by brain's visual system. These systems will be highly sensitised and people like Kris who engage these systems in a frequent and highly specialised manner, these systems can evoke a conscious perception like a memory trace offsets (44:33) and this is partly why people have had limbs amputated feel phantom limb sensations such as a natural pain in say, a hand has been amputated. That's because despite of the limb being gone and the brain apparatus is still there, so that just fire off and evoke these sort of conscious perceptions of something that's not actually there.

Hannah - So, he's kind of almost developed a highly sensitive or maybe he was born with a highly sensitive kind of auditory perception of sound system in his brain and there's nerve cells that are being activated by things that he's not even consciously aware of. Are the sounds actually there or are they coming from his imagination from his head?

Martin - I think maybe a good way to think about this is the old adage of, if a tree falls in the forest, nobody is there to hear it. It doesn't make a sound. The answer is actually quite simple. It doesn't release sound waves into the environment without a nervous system to take those sounds waves and then process those sound waves also through you know, in our ear, through our auditory system inside of the brain and then into the brain, we actually would not have what we know to be conscious perception of sound. So yeah, he's experiencing I guess as the same system that his brain is becoming active without the environmental stimuli.

Katie - I mean, these experiences is a lot more common than many people expect. There's an understanding of mental health disorders as being extremes of experiences that people in the normal population on the healthy population experience. But it's when these become problematic and affect the functioning in daily life that they become what we would refer to as a disorder. One of these continuums is known schizotypy. It refers to the fact that many people in the general population sometimes experience similar types of experiences. And these people have Schizophrenia so hearing and seeing things that aren't there and hallucinations which can happen in any sensory modality including touch, taste. Some people are just more susceptible to these experiences than others. So, it's a sort of scare with some people being more and some people being less Schizotypal. It's important to emphasise that having this experience is not the same thing as having a disorder. There's a number of theories as to why people have hallucinations. One of these popular theories suggest that it might stem from the sort of heuristics and shortcuts predictions that people's brains use to help them interpret everything that's going on around them, and to sort of select the information that's useful to them. So, you monitor what your actions are, your deliberate actions, and use that to predict what you expect from say, your own feedback.

Hannah - And Kris suffers from these hallucinations either auditory sound hallucinations at night. So, it's not intruding on his day to day life. It's an experience that he's also got an insight into. And so, he can almost predict that it shouldn't be there in the environment and it's unexpected that it is there in the environment but he has that insight to know that it's not somebody outside in the space, telling him to do something or producing a particular sound that might frighten him.

Roger - And that, a particular kind of again, manoeuvre can be very useful clinically. It's almost like a mindful detachment kind of mode. So, whatever it is, it's just noticing it and letting it go rather than dwelling on it or interpreting it, just allowing the phenomenon to be there and then letting it pass. That can be really helpful.

Martin - I think it sounds so interesting Kris this just happens just before he is falling asleep because I kind of personally know when I'm falling asleep because my thoughts get very abstract. Again, I'm aware that I'm not going crazy. The thoughts do get very abstract and wild and strange to me. I've got used to that and actually, I get quite happy when that happens because I think, okay, I'm falling asleep now.

Roger - I think there's a school of thought around hypnosis that when we're in that kind of trance like the hypnagogic type state, conscious controls come off a little bit. Say, I might think I'm actually playing the centre forward for England, but of course, it isn't true. As you say, a well-recognised phenomenon.

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