The history of attention and focus?
1850s to 1920s
In James’ time, the only method available to study attention was introspection. Very little progress was made in quantifying the study of attention, though it was considered a major field of intellectual inquiry by such diverse authors as Sigmund Freud, Walter Benjamin, and Max Nordau. For example, one major debate in this period was whether it was possible to attend 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.
1920s to 1950s
From the 1920s to the 1950s, the field of attention was relatively inactive. The dominant psychological paradigm at the time was Behaviorism. This view was defined by an epistemology called Positivism, which does not permit assumptions about processes that cannot be observed directly (e.g. cognitive processes, gravitational forces in physics). Thus, the cognitive processes that govern attention were not considered legimitate objects of scientific study.
1950s to present
In the 1950s, psychologists renewed their interest in attention when the dominant epistomology shifted from Positivism to Realism during what has come to be known as the cognitive revolution (Harré, 2002). The cognitive revolution admitted unobservable cognitive processes like attention as legitimate objects of scientific study.
Cherry and 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 subjects questions about the content of the unattended stream.
Main article: Dichotic listening studies in attention
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 cannot access consciousness. This debate has still not been resolved.
In the 1960s, Anne Treisman began developing the highly influential Feature integration theory (first published under this in a paper with G. Gelade in 1980). According to this model, attention is responsible for binding different features into consciously experienced wholes. Although this model has received much criticism, it is still widely accepted or held up with modifications as in Jeremy Wolfe’s visual search paradigm.
In the 1960s, Robert Wurtz at the NIH began recording electrical 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 1990s, psychologists began using PET and later MRI to image the brain in attentive tasks. Because of the highly expensive equipment that was generally only available in hospitals, psychologists sought for cooperation with neurologists. Pioneers of brain imaging studies of selective attention are psychologist Michael I. Posner (then already renown for his seminal work on visual selective attention) and neurologist Marcus Raichle.[How to reference and link to summary or text] Their results soon sparked interest from the entire neuroscience community in these psychological studies, which had until then focused on monkey brains. With the development of these technological innovations neuroscientists became interested in this type of research that combines sophisticated experimental paradigms from cognitive psychology with these new brain imaging techniques. Although the older technique of EEG had long been to study the brain activity underlying selective attention by cognitive psychophysiologists, the ability of the newer techniques to actually measure precisely localized activity inside the brain generated renewed interest by a wider community of researchers. The results of these experiments have shown a broad agreement with the psychological, psychophysiological and monkey literature.