attention or does not (i.e. is automatic) is clearly a drastic over-simplification
if there are a number of different attentional processes. In similar fashion, it
may not be sensible to ask whether attentional selection occurs early or late in
processing if there is no unitary attentional system. In the words of Allport
(1993, pp. 203–204):
There is no one uniform function, or mental operation (in general, no one
causal mechanism), to which all so-called attentional phenomena can be
attributed....Itseemsnomoreplausiblethatthereshouldbeoneunique
mechanism, or computational resource, as the causal basis of all atten-
tional phenomena than that there should be a unitary causal basis of
thought, or perception, or of any other traditional category of folk psy-
chology.... Reference to attention (or to the central executive, or even to
the anterior attention system) as an unspecified causal mechanism explains
nothing.Functions of Attention
A major limitation of most theories of attention, and the research to which they
have given rise, is that the functions of attention receive little consideration.
In most research, what subjects attend to is determined by the experimental
instructions. In the real world, however, what we attend to is determined in
large measure by our motivational states and by the goal we are currently
pursuing. This point is emphasised by Allport (1989, p. 664): ‘‘What is impor-
tant to recognise ... is not the location of some imaginary boundary between
the provinces of attention and motivation but, to the contrary, their essential
interdependence.’’
Concern with the functions of attention suggests that attention theorists may
need to change the focus of their research. For example, Allport (1989, 1993)
identified the following (relatively uninvestigated) issues as being of major
importance:
.Segmentation of different parallel processing streams.
.Priority assignment among multiple goals.
.Co-ordination between sensory input and action: selection for action.
Chapter Summary
The concept of ‘‘attention’’ is generally used in connection with either selective
processing or mental effort and concentration. Selective attention has been
investigated in studies of focused attention, in which the subject’s task is to re-
spond to one stimulus (the attended stimulus) and to ignore the other stimulus
(the unattended stimulus). The issue of what happens to the unattended stim-
ulus has been investigated in the auditory and visual modalities. Studies in the
auditory modality suggest there is typically some processing of unattended
stimuli, with the amount of such processing varying as a function of how easy
it is to discriminate between the attended and unattended stimuli. Similar
findings have been obtained when focused attention has been investigated in
the visual modality.
394 Michael W. Eysenck and Mark T. Keane