6 Concluding thoughts
We seem to have come a long way and covered a great deal of ground since I approached this subject by explaining that a mechanism must exist to help us focus on one sound out of many. That clearly is one function of attention, but attention seems to have other functions too. The results of visual search experiments show that attention is a vital factor in joining together the features that make up an object, and the experiences of brain-damaged patients suggest that this feature-assembly role ensures that our conscious perceptions are generally of objects, rather than of their constituent parts. Cross-modal research has demonstrated that the gathering together of related information from different senses is also controlled by attention.
Attention has a role to play in dealing with competition. The early researchers believed that attention was vital, because the brain would be able to deal with only one signal at a time; a ‘winning’ signal had to be picked from among the competitors. Although we have shown that a good deal of analysis can actually take place in parallel, there are also results which suggest that more complex analysis is largely serial, thus requiring a mechanism to select from the competing stimuli. Often, the parallel processes have to be demonstrated rather obliquely, since their results do not become consciously available. Thus attention has to do with what reaches conscious awareness. Why should this be so? Why should we not be equally aware of several items simultaneously?
Allport (1987) offered an answer that suggests yet another role for attention: it is to direct actions. Although we might, in principle, be able to perceive many things at once, there are situations where it would be counterproductive to attempt to do more than one thing. Allport gave fruit-gathering as an example. When we look at a bush of berries we need to focus attention upon one at a time, since that is how they have to be picked. If animals had not evolved this ability to select, if all the food items remained equally salient, they would starve as they hovered over them all, unable to move toward any one! From this perspective, attention is the process that saves us from trying to carry out incompatible actions simultaneously. However, everyday experience reminds us that the issue of consciousness remains relevant. For example, novice drivers experience considerable difficulty in trying simultaneously to perform all the actions needed to control a vehicle; in Allport's view they are trying to ‘attend-for-action’ to more than one thing at a time. However, this could be restated as an attempt to be conscious of more than one thing at a time. Once the driver has become more skilful, the difficulty of combining actions disappears, but so too does the driver's conscious awareness of performing them: they have become automatic.
Box 3 Research study: Hypnosis, time and attention
Brain scanning has revealed that regions of the brain known to be involved in attention show unusual activity when hypnotised participants become tolerant of pain (Crawford et al., 1998), or experience hallucinations (Szechtman et al., 1998).
Many people are unable to achieve such extreme effects in hypnosis, but there is one phenomenon that almost everyone experiences: hypnosis sessions usually feel to have lasted for far less time than the actual duration. I have explained this observation (Naish 2001, 2002) by linking it to Gray's (1995) theory of consciousness, which involves some of the same brain regions. He proposed that we maintain the content of our conscious awareness by registering repeated ‘snapshots’ of our environment. Our sense of time may be linked to the rate at which the environment is sampled.
To become hypnotised usually involves an induction in which one is asked to relax and focus attention on internal feelings, such as the heaviness of limbs or the rate of one's breathing. Subsequently, one is invited to imagine and attend to a pleasant, relaxing scene. Neither of these activities produces fast-changing streams of stimuli; the bodily feelings change only slowly and the relaxing scene is self-generated, so changes only when one wants it to change. I propose that in these circumstances there is no need to take such frequent snapshots, since little will change from one to the next. Consequently, we are less aware of the passage of time. In support of this claim, it turns out that participants who rate themselves as more successful at attending to their self-generated experiences and ignoring the real world are those who make larger underestimates of the session duration (Naish, 2003).
One might well ask how the term ‘attention’ has come to be applied to so many roles and processes; it might have been better to use different labels to distinguish between them. To use one word with so many aspects certainly makes a unitary definition very difficult to formulate. I suspect that the single term has stuck because ultimately all these facets of attention do lead to one result: conscious awareness. Even in so-called altered states of consciousness, such as hypnosis, attention appears to be a vital component (see Box 3). To conclude with a personal view, I will offer the following definition:
Attention is the process which gives rise to conscious awareness.
I promised at the start of this course that attention was a broad and intriguing topic. I am sure you will agree that it was broad – and we haven't covered half of it – but I hope you are now intrigued too. It is generally accepted that readers cannot continue to devote attention to text that goes on too long, so I trust that I have stimulated, rather than sated, your attention!