You are about to make a speech in front of a large audience. Do you get butterflies in your stomach, does your heart race and is your breathing restricted? How can that happen?

We all talk about the five senses. We see, we hear, we touch, we smell and we taste. We have other senses that are seldom visible. We are all sensing the internal state of our body all the time. We sense hunger, thirst and fatigue. We feel our stomach muscles when we eat too much. We monitor our heart rate all the time but are seldom aware that we are doing it. We have many such inputs coming into our brain. There are so many that they would interfere with our sensing of the external world. Our brain monitors them in the background. This is interoception.

For some people that background monitoring is visible. They do sense their own heartbeat. If asked to assess their own heart rate they can do it and with some accuracy. There are a small number of people who enjoy feeling their heartbeat. They sometimes wear tight tops to amplify the effect. For others it can be a disturbing interference.

Studies have shown that our heartbeat can indeed influence our external senses. Respondents were asked to monitor symbols flashed on a screen. If the flashing is co-ordinated with their heart beat the symbol often disappears. Other studies have shown that we time our hearing to coincide with different phases of our heartbeat. Our senses internal and external operate as an integrated whole.

Proprioception and the Vestibular System

We have another hidden sense. How can we bring a cup of coffee to our lips without conscious thought? We know where our body is in space. We know where our hand and arm are relative to our mouth. We know exactly the force needed to bring the cup to our lips without spilling it. We can walk through a room full of furniture without bumping into it. Suppose, however, that we do trip. We can regain our balance. The vestibular system in our inner ear is our sense of balance and is sensitive to gravity. Our vision combines with it to tell us what we need to do. Our proprioception tells us how to move our body, arms and legs to maintain our balance. All without conscious effort.

Our Hidden Senses and Our Emotions.

There are multiple different sensory systems operating in the background. There is a two-way connection between those hidden senses and our emotions. Our anxiety at giving a speech is made manifest through those butterflies. Anxiety is associated with a faster heartbeat. Such a heartbeat can induce a sense of anxiety. When we sleep our heart rate does vary. If we happen to wake during a period of increased rate our mind may become anxious in response. We start to worry about all the things that we have forgotten. All because of something beyond our control.

Our body likes to be in a steady state: homeostasis. If it needs hydration it signals to our body through a dry mouth. If our internal signals are wrong it does influence our emotional state. We really do have “a gut feeling”.

In a previus Newsletter I looked at the design of a completely new shopping trolley. They replaced the horizontal pushing bar with two handles comparable to a wheel barrow. These were on either side of the trolley. They were about 10 centimetres lower than the traditional handle. The new design induced shoppers to spend more than the normal design. Not only did they spend more money they bought more items. Not only more items but more unique items. The trolley seemed to induce “impulse purchases”. Only the buying of “stockpile” products did not change. Clearly the new design tapped into the inner senses of the body and triggerred an emotional reaction.(See Newesletter #40 Shopping Carts and Perception)

So called psychosomatic symptoms are often our hidden senses made visible. If the placebo effect is in operation, we will look for the relevant symptoms.(See Newsletter #228 Placebo and Nocebo) We might believe, for whatever reason, we have hypertension. We can often find the signals we need to justify this thought already present in our body. Mind and body should never be seen as separate. Interoception varies by individual. Some of us are more attuned to those inner feelings. There is some evidence that sufferers of ADHD may have under performing inner senses

The Effect of Ageing.

Ageing typically leads to a decline in the sense of the bodies internal state. It reduces the accuracy of detecting those sensations. It weakens the link between our emotions and our bodily sensations. Strangely we may feel more aware of of our internal feelings even though we a less good at detecting them. The decline seems to impact an older person’s ability to regulate their emotions. It can influence their overall mental health