Selective vs. Divided Attention Selective attention: Process one stimulus while ignoring another. Divided attention: Process both stimuli, by giving some attention to each. Shadowing: Dichotic listening task where input from one ear is repeated aloud. Selective attention to the shadowed message results in the ignored message not being perceived and remembered.
Filter Theories: Early Selection Attentional filter operates after sensory processing but prior to meaningful semantic processing. Explains why ignored messages in shadowing task cant be rememberedthey were not semantically processed. Explains why sensory features of the ignored message (e.g., pitch) are processed and remembered.
Filter Theories: Attenuation Failures of selective attention occasionally occurfor example, noticing ones own name in the ignored message. An attenuation filter lowers the strength of the sensory signal in the ignored message, making it less likely to be perceived. Important stimulisuch as ones name pass through the filter without attentuation.
Filter Theories: Late Selection However, experiments showed even unimportant stimuli received semantic analysis. For example, semantic priming from a stimulus that backward masking deletes from conscious perception. Late selection filter occurs after sensory and semantic analysis but before response selection.
Capacity Theories of Attention Depending on the task used, the filter seemed to be either early or late in processing. The ability to divide attention instead of selectively attend was also important to model. Capacity theories drop filters and assume attention is limited in overall capacity. Mental effort: the proportion of available attentional capacity given to a task.
Capacity Theories of Attention Single capacity: Assumes attentional capacity is undifferentiated. Multiple resources: Assumes there are multiple attentional capacities. auditory vs. visual perceptual modalities perceptual vs. cognitive resources vocal vs. manual response modalities
Automatic Processes Stroop Effect: Color names are printed in compatible or incompatible ink colors. Task is to name the ink color. Errors and response times increase for incompatible (RED printed in green ink) compared with compatible (RED printed in red ink).
Visual Attention Visual attention is like a spotlight on the visual field. Brain circuits read out the contents of the spotlight, disengage it, and move it to a new location. Spatial Neglect: A breakdown in visual attention whereby some areas of the visual field are not perceived.
Executive Attention Attention given to manipulating and controlling mental representations and processes. Supervisory attentional system that inhibits inappropriate responses and activates appropriate ones. Anterior cingulate gyrus deep in the frontal lobe inhibits automatic responses in Stroop task, for example.
Perceptual Binding Visual attention is needed for integrating stimulus features (e.g., color, shape, and location) in perception. Inattentional blindness and attentional blink illustrate failures to bind features in the absence of attention.
Subliminal Perception Perception without attentionaccording to feature integration theory, unattended stimuli are unbound features and thus not perceived. However, individual features do register because of pre-attentive processing and can be measured on appropriate test. Familiarity and emotional preference also register from subliminal stimuli.