Perceptual tunnelling

Most people are aware of having a field of vision. That is how much you are aware of in your peripheral vision to the right and to the left and above and below when you are looking straight ahead.

People may also be aware of what we call ‘visual field loss’. This is where for instance in glaucoma the visual field in the mid-periphery (that is not in the middle, not at the edges though inbetween) is lost due to changes in the health of the nerve at the back of the eye.

However, there is another effect that can occur with the field of vision. This effect is more subtle and is called ‘perceptual tunnelling’.

This is when your ‘perceptual field of vision’, that is what you are aware of in your field of vision, is reduced due to stress.

You may have noticed this effect yourself when you are looking for your housekeys when you are in a hurry.

You then find that your housekeys are directly in front of you. What has happened is that because of the stress, your ‘perceptual field of vision’ has temporarily become smaller, a bit like looking through a narrow tube or down a tunnel.

This gives rise to the term ‘perceptual tunnelling’.

Because you have been ‘perceptually tunnelling’ you have found it more challenging to find your keys.

Please note that this is not a health condition and instead is a ‘perceptual effect’.

In people with learning problems or people who may have been under stress for a long time, they have learnt to permanently ‘perceptually tunnel’.

They perceive the world as it they are looking down a narrow tube or down a telescope.

In theory, if their perceptual field of vision was open to its full extent they would become overwhelmed by too much sensory information. Perceptual tunnelling has become their ‘coping mechanism’. However, being able to cope does not mean that they are performing efficiently.

If you are perceptually tunnelling all the time, it is a bit like looking at the world through a piece of A4 paper that has been rolled up into a tube. You have to move your head constantly to find what you are looking for. In doing this you are attempting to get your ‘limited perceptual field of vision’ to fall on the object you are looking for.

Children or adults who perceptually tunnel may well bump into things or people or jump a queue because they are not aware that the objects are there, the people are there or the queue is there.

Their room may not be tidy because they are not able to perceive the whole of the room at the same time.

They are only able to perceive a small bit of the room at a time so are not aware of the whole of the room not being tidy.

The position of objects in their environment may be obvious to you (eg see that bird over there) though not be obvious to them.

They are not looking in the right place to find the object you are pointing to given the fact that they are perceptually tunnelling.

Knowing that people are perceptually tunnelling can be useful because it means that you can cut them some slack. You now have a reason for their behaviour.

It is also helpful for you to know about perceptual tunnelling particularly when you are walking down the street.

You may notice someone walking straight towards you. More than likely they are perceptually tunnelling and unless you move out of the way they are going to walk straight into you.

 Successfully working through a vision training programme will potentially reduce perceptual tunneling as well as improve visual skills, attention, speed of visual processing and balance.

This will lead to increased relaxation so reducing levels of stress. As your level of stress reduces you are less likely to perceptually tunnel.

There is another intervention that can be used to reduce ‘perceptual tunnelling’ called ‘syntonic phototherapy’ which will be explained in another section.