Perception and Attention
Ronald A Rensink, University
of British Columbia
In
D. Reisberg (ed). Oxford Handbook of
Cognitive Psychology. Oxford: University Press. pp. 97-116. [pdf]
Our
visual experience of the world is one of diverse objects and events, each with
particular colors, shapes, and motions. This experience is so coherent, so
immediate, and so effortless that it seems to result from a single system that
lets us experience everything in our field of view. But however appealing, this
belief is mistaken: there are severe limits on what can be visually
experienced.
For
example, in a display for air-traffic control it is important to track all
moving items. For a single item,
this can be done without problem. Three or four can also be tracked, although
some degree of effort may be needed. As the number is increased further,
accurate tracking becomes more and more difficult--and eventually, impossible.
Performance is evidently affected by a factor within the observer which enables
certain kinds of perception to occur, but is limited in some way. This factor
is generally referred to as attention.
At
various times, attention has been associated with clarity of perception, intensity
of perception, consciousness, selection, or the allocation of a limited "resource"
enabling various operations (see Hatfield, 1998). During the past several
decades, considerable progress has been
achieved
by focusing on the idea of selection (Broadbent, 1982). In particular,
attention can be productively viewed as contingently selective processing. This
can be embodied in various ways by various processes--there need not be a
single quantity identified with all forms of attention,
or
a single site where it operates (Allport, 1993; Tsotsos, 2011). Although
"paying attention" is often considered to be a unitary operation, it
may simply refer to the control of one or more selective processes, ideally in
a co-ordinated way. While this
view has some cost in terms of conceptual simplicity, it can help make sense of
a large set of phenomena.
This
article surveys several of the major issues in our understanding of attention
and how it relates to perception. It focuses on vision, since many--if not
all--considerations are similar for all sensory modalities, and the level of
understanding achieved in this domain is currently the most advanced. Although many of the issues discussed
here also apply to higher-level cognitive processes, coverage of those is best
done separately.