The subject of attention is a relatively new one to psychiatry, as the notion of attention, prior to the Industrial Age, was thought to be adequately addressed by corporal punishment. If a serf did not work they were either punished (by corporal punishment), or foced from their home and left to starve on the roadsides. Obtaining taxes, revenue, rents, etc. was simply a matter of force.
In the industrial era, early on, attention disturbances led to industrial accidents, and so, had their own direct consequence - mortality, disfigurement, and with the same consequence, homelessness and starvation or death in the face of the elements.
In a post industrial age ("the information age"), losses of attention lead to loss of income.
If a child in a school does not attend, no matter what that child's potential, the outcome is the same. The child does not have access to the same education, and so is forced into (as a general rule) a lower paying empolyment.
To answer the question, not so much with reference to social outcomes, but rather with reference to psychiatric outcome, we then turn to the much more immediate question - what is the biological origin of a disturbance in attention ?
Attention, of course, is a relative matter. Humans have natural and full attention to many matters, even in the most dire of circumstance.
In fact, the only form of loss of attention that is fatal is dementia. In dementia, early loss of attention is much more significant than loss of memory.
This topic gets little discussion in the literature, in part, because diagnostics in Child and Adolescent Psychiatry attempts to separate the clnical phenomena in children from that of adults (and older adults).
However, the scale of attentional loss in in dementia is to such an extent, that, as noted above, it becomes in many cases the first finding of illness.
Thus, we are obliged to point out that disturbances of attention, as a congnitive finding, can only be considered a specific illness when other causes are excluded.
Here is one cause that may be the most attributable of all. We know that humans now live in an artificial environment, one of our own making to be sure. Are we biologically adapted to that environment ? Or, is it possible that we are not adapted to our new environment ?
The answer lies in the question of whether or not there is a specific (that is to say, a minimum) amount of evolutionary pressure to force such changes in the human genome as a whole, (of course, making the assumption that such force has a elastic portion of the genome to make its effect). And the latter is by no means assured. So we are probably correct to be skeptical that such an evolutionary adjustment has occured.
So it is not amiss, then, to describe disturbances in attention as consequences of environmental change, rather than genomic change. This hypothesis, one meeting basic scientific criteria, can be considered useful but not comprehensive.
As noted above, many illnesses can manifest with disturbances of attention as principal features.
Examples include almost every category of psychiatric illness (schizophrenia, affective illnesses, forms of anxiety, the effects of toxic substances, and a host of developmental disabilities).
So, in some ways, the propoer question to ask is not "is there an attention deficit" but rather "is there an attention deficit which meets no illness criteria ?".
Should we expect that there is ? Before we speculate about its existence, we should be clear about what its appearance should consist of.
Let us take the example of a child who, if perfectly average, would have certain sorts of reponse to certain sorts of stimuli. On one side of the room is the child's favorite toy. On the other side of the room, a toy which is not the child's favorite (perhaps even least favorite). On the whole, we would expect the child with abnormal attention to attend to the unfavored toy. A bit of a thought experiement. Has such an experiment been done ?