Tunnel vision is a peculiar phenomenon that affects the ability to perceive the stimuli of our environment. It is relatively frequent that, when we are in a marked state of psychophysiological stress, we pay attention exclusively to that which is related to the task, threat or main concern that occupies us.

In this article we will describe what tunnel vision is and what causes it . In order to do so, we will briefly review the cognitive theory on the different modalities of attention, and explain the difference between the concept of tunnel vision in psychology and its use in medicine.

Attention as physiological activation

Attention is a broad psychological function, and as such the alterations that affect it can give rise to very diverse phenomena. Thus, for example, if we consider attention as the ability to select a stimulus and focus our cognitive resources on it, we can identify disorders of this function in schizophrenia or in manic episodes.

Attention-related alterations have also been described as concentration (such as mental absence and time gap), as vigilance (which in generalized anxiety disorder has the character of ‘hypervigilance’), as expectations (a relevant aspect in psychosis) and as physiological activation, associated with the experience of stress.

The phenomenon of tunnel vision is part of this last area of analysis of attention processes. However, it is an ambiguous concept that has not only been used in the field of psychology, but has also been discussed in medical contexts, particularly in ophthalmology.

What is tunnel vision?

From the point of view of cognitive psychology, tunnel vision is an alteration of attention that occurs in situations of intense stress , particularly when a sense of threat is experienced. However, this does not always correspond to reality, and some individuals are more prone to tunnel vision than others.

Specifically, it has been proposed that introverted people have a greater tendency to tunnel vision than extroverted people, if we understand these two constructs as defined by Eysenck: as manifestations of the base level of activation of the cerebral cortex. Thus, introverts are more prone to this phenomenon because of their higher level of general anxiety.

Tunnel vision is also less common in children and the elderly than in people of intermediate age; this is also due to differences in cortical activation. On the other hand, as is logical, the experience of situations that are objectively threatening for a given person increases the probability of tunnel vision.

In the general medical context, the concept “tunnel vision” is normally used to refer to the loss of peripheral vision capacity, as occurs in glaucoma. People with this impairment can only see clearly the central part of their visual field; this results in the perception of the field being roughly shaped like a tunnel.

However, in the psychology of attention the term has a more abstract character ; many experts do not only include within it the visual alterations caused by stress, but the narrowing of attention to which it is due can affect other senses in the same way. It is worth noting that hearing is almost as important as sight for humans.

Causes of this phenomenon

Tunnel vision understood as an attentional phenomenon is due to specific hypervigilance, i.e. selective attention to stimuli that are associated with a potential threat to safety or survival. This makes it easier for us to attend to the stimuli we consider relevant, but reduces the capacity to perceive the rest of the factors of the situation.

Cortical activation depends largely on the release into the bloodstream of stress hormones, the most important of which are corticosteroids. This occurs more markedly the higher the person’s perception of stress, the more intense the physical and mental activity he or she executes and the more demanding the situation.

Many cognitive models of attention focus on the fact that our attentional resources are limited, so we can only focus our perception on one or another stimulus by dividing these capacities in different ways. In this sense, it is important to remember that there are several types of attention: selective, focused, divided…

When tunnel vision takes place, our sight, and often the other senses as well, are focused only on the stimuli we associate with that which concerns us most. This leads to our probability of adequately perceiving the rest of the stimuli being very markedly reduced, diminishing the quality of our behaviour.