It is worth considering that numbers can either signify absolutes – a quantifiable amount, as in statistics – which would suggest an affinity with the left hemisphere, or signify relations, which would suggest an affinity with the right hemisphere.

Changes in novelty or complexity can mask relevant structures or falsely identify irrelevant ones.26 The more complex the task, the more widely distributed the networks involved are likely to be, and the harder it will be to know what it is that one is measuring; subtraction paradigms, where two sets of conditions are compared so as to isolate the

Food, however, and musical instruments, presumably because of the intimate way in which they take part in the life of the body, sort with the living rather than the non-living.

Some particular circumstances make split-brain subjects especially intriguing. If an image is shown to a split-brain subject in the left visual field, he or she will be unable to name what was seen, since the image from the left visual field is sent to the right side of the brain only, and the right hemisphere in most subjects cannot speak. Since

keeping with this, attention is inescapably bound up with value – unlike what we conceive as ‘cognitive functions’, which are neutral in this respect. Values enter through the way in which those functions are exercised: they can be used in different ways for different purposes to different ends. Attention, however, intrinsically is a way in which,

Brain regions involved in conscious identification of colour are probably left-sided, perhaps because it involves a process of categorisation and naming;288 however, it would appear that the perception of colour in mental imagery under normal circumstances activates only the right fusiform area, not the left,289 and imaging studies, lesion studies

For the same reason that the right hemisphere sees things as a whole, before they have been digested into parts, it also sees each thing in its context, as standing in a qualifying relationship with all that surrounds it, rather than taking it as a single isolated entity.131 Its awareness of the world is anything but abstract.

To sum up, the right hemisphere is responsible for every type of attention except focussed attention.

The conventional neuropsychological literature distinguishes five types of attention: vigilance, sustained attention, alertness, focussed attention and divided attention. While not identical, vigilance and sustained attention are similar, and they are often treated as one concept. Together with alertness, they form the basis of what has been called