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The word attention refers to the cognitive process of
selectively concentrating on one thing while deliberately ignoring other things. Examples include listening carefully to what
someone is saying while ignoring other conversation in the room. Attention can also be split, such as driving, putting on makup,
and talking on the cell phone at the same time.
Attention is one of the most intensely studied subjects within psychology
and cognitive neuroscience. Of the many cognitive processes associated with
the human mind (decision-making, memory, emotion, etc) attention is considered the most concrete because
it is tied so closely to perception. As such it is a gateway to the rest of
cognition.
The most famous definition of attention was provided by one of the first major psychologists, William James:
"Everyone knows what attention is. It is the taking possession by the mind in clear and vivid form, of one out of what seem
several simultaneously possible objects or trains of thought...It implies withdrawal from some things in order to deal
effectively with others." (Principles of
Psychology, 1890)
History of the study of attention
1850's to 1920's
In James' time, the only method available to study attention was introspection. Very little progress was made in adding rigor to the field. For example, one major debate in
this period was whether it was possible to attentd to two things at once (split attention). Some thinkers
felt that they were unable to do so, and other thinkers felt that they could. Without experiments, it was impossible to settle
the debate.
1920's to 1950's
From the 1920's to the 1950's, the field of attention was relatively inactive. Behaviorism, the then-dominant paradigm was strongly opposed to anything cognitive (in part as a reaction to
the endless debates of the introspectivists), and there were still no tools for quantitative measurements.
1950's to present
In the 1950's, the cognitive revolution began, and psychologists renewed their interest in attention. Cherryand Broadbent,
among others, performed experiments on dichotic listening. In a typical experiment, subjects would listen to two streams of words in different
ears of a set of headphones, and
selectively attend to one stream. After the task, the experimenter would ask the subject questions about the content of the
unattended stream.
During this period, the major debate was between early-selection models and late-selection models. In
the early selection models, attention shuts down processing in the unattended ear before the mind can analyze its semantic
content. In the late selection models, the content in both ears is analyzed semantically, but the words in the unattended ear are
prevented from accessing consciousness. This debate has still not been resolved.
In the 1960's, Anne Triesman
developed the highly influential Feature Integration Theory. According to this model, attention is responsible for binding
different features into consciously experienced wholes. Although this model has recieved much criticism, it is still widely
accepted.
In the 1960's, Robert Wurtz at
the NIH began recording eletrical signals from the brains of macaque monkeys who were trained to perform attentional tasks. These
experiments showed for the first time that there was a direct neural
correlate of a mental process (namely, enhanced firing in the superior colliculus).
In the 1990's, neuroscientists began using fMRI to image the brain in attentive
tasks. The results of these experiments have shown a broad agreement with the psychophysical and monkey literature.
Current research
Attention remains a major area of investigation within psychology and
neuroscience. Many of the major debates of James' time remain unresolved.
For example, although most scientists accept that attention can be split, strong proof has remained elusive. And there is still
no widely-accepted definition of attention more concrete than that given in the James quote above. This lack of progress has led
many observers to speculate that attention refers to many separate processes without a common mechanism.
Areas of active investigation involve determining the source of the signals that generate attention, the effects of these
signals on the tuning properties of sensory neurons, and the relationship between attention and other cognitive processes like working memory. Some speculative research has even shown that flies may be able to attend (using a brain the size of a poppy seed) in much the same way neurologically as humans
do.
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