Broadbent's filter model of attention
Donald Broadbent based the development of the filter model from findings by Kennith Craik, who took an engineering approach to cognitive processes.
[3] Unlike the physical properties, Broadbent believed semantic features, due to their complexity, would impose a limited capacity on the temporary storehouse of incoming stimuli.
Further, goal-directed behaviour requires attention to be controlled; hence a high degree of selectivity is put forth in the information-processing stream.
When developing his model, Broadbent emphasized the splitting of incoming stimuli to attended or unattended channels.
Following the listening period, the participants are tested on whether they recall any information presented in the unattended channel.
[10] Broadbent used this paradigm in his split-scan experiments, in which he presented participants with different letters in each ear simultaneously and instructed them to repeat them in any order.
[6] As psychological research has improved immensely since Broadbent's time, more sophisticated measures indicate that we do have an attentional filter, though it is integrated into a broader cognitive system.
[4] This system compensates for the controversies of limited parallel processing in Broadbent's original findings.
[13] Additionally, research has shown that physical features of a stimulus guide attentional selection.
[12] Research has shown that the speech is more apt to objective interpretation than inputs to the visual system.
[14] More recent research finds that Broadbent's model neglected to address the time requirements of shifting attention.
[15] Treisman stated that instead of a filter, people have an attenuator and it identifies messages based on its physical properties or by higher level characteristics, such as meaning.
It is the progression by which external stimuli form internal representations that gain conscious awareness.
A filter can be regarded as the selector of relevant information based on basic features, such as color, pitch, or direction of stimuli.
[3] The basic idea proposes that perception of the stimulus is not required prior to selecting its relevance.
This study suggested that information is filtered according to basic characteristics of the stimuli (e.g., the ear in which it was presented).
Therefore, when required to report the digits in the order they were presented, participants had to continuously switch filters, which impacted accuracy.
[22] This notion implies that internal decisions of stimuli relevance must be made, before allowing it to gain conscious awareness.
Gray and Wedderburn[23] showed evidence of late selection using a split-span technique similar to Broadbent.
This study suggested that stimuli are not selected based on physical characteristics (e.g., location of sound) determined by the filter but according to meaning.
Anne Treisman, though influenced by Broadbent's work, was not fully convinced by the notion of a filter performing decisions as to what stimuli gain conscious awareness.
[25] Deutsch and Norman were not fully convinced by Broadbent's selection criteria based solely on physical features of a stimulus.
[3] However, attended and unattended information pass through the filter, to a second stage of selection on the basis of semantic characteristics or message content.
Within this model, attention is assumed to be flexible, allowing different depths of perceptual analysis.
[3] In addition, his model incorporates the ideas of voluntary and reflexive attention, which affect allocation policy.
