CH 4

Processing Capacity and Perceptual Load in Attention

• Lavie considers processing capacity and perceptual load in attention
• Processing capacity sets a limit on the ability to process incoming information
• Perceptual load is related to the difficulty of a task
• Forster and Lavie studied distraction in relation to processing capacity and perceptual load
• The study used displays with targets surrounded by different letters
• Results showed longer reaction times for harder tasks and slower response to distracting stimuli
• Lavie's load theory of attention explains the impact of processing capacity and perceptual load
• In low-load tasks, processing capacity remains, allowing processing of task-irrelevant stimuli
• In high-load tasks, no processing capacity remains, making distraction less likely
• The ability to ignore task-irrelevant stimuli depends on the task load and the stimulus power
• Stroop effect demonstrates difficulty in ignoring task-irrelevant stimuli
• Participants are asked to name the color of the ink used to print shapes in a demonstration

Different Aspects of Attention in Cognitive Psychology

• Roger's experiences illustrate different aspects of attention, including selective attention, distraction, divided attention, attentional capture, and visual scanning.
• Selective attention is the ability to focus on specific stimuli while ignoring others, as illustrated by Roger focusing on his math homework while ignoring people talking.
• Distraction occurs when one stimulus interferes with the processing of another stimulus, as seen when the conversation in the library interfered with Roger's cell phone game.
• Divided attention is the ability to pay attention to more than one thing at a time, as demonstrated when Roger decided to listen in on a conversation while playing a game.
• Attentional capture refers to the rapid shifting of attention caused by a stimulus, such as a loud noise, bright light, or sudden movement, exemplified by the noise of the overturned book cart interrupting Roger's eavesdropping.
• Visual scanning involves movements of the eyes from one location or object to another, demonstrated by Roger's attempt to identify the people across the room.
• William James's definition of attention captures the withdrawal from some things in order to deal effectively with others, but it doesn't capture the diversity of phenomena associated with attention.
• Attention is not one thing; there are many different aspects of attention studied using different approaches.
• Modern research on attention began in the 1950s with the introduction of Broadbent’s filter model of attention, which explains the results of Colin Cherry's dichotic listening experiment.
• Dichotic listening experiments confirmed that people are not aware of most of the information presented to the unattended ear, as shown by participants being unaware of a word repeated 35 times in the unattended ear.
• The cocktail party effect refers to the ability to focus on one stimulus while filtering out other stimuli, such as focusing on what one person is saying at a noisy party.
• Donald Broadbent's filter model of attention explains how it is possible to focus on one message and why information isn’t taken in from the other message.

Broadbent's Model of Attention and Treisman's Modification

• Broadbent's model introduced the flow diagram to cognitive psychology
• The model proposed that information passes through stages: sensory memory, filter, detector, short-term memory, and long-term memory
• It is an early selection model as the filter eliminates unattended information at the beginning
• Neville Moray's experiment tested Broadbent's theory and found that unattended information is processed to provide awareness of its meaning
• J.A. Gray and A.I. Wedderburn's "Dear Aunt Jane" experiment supported Moray's findings
• Anne Treisman proposed a modification of Broadbent's model, replacing the filter with an attenuator
• The attenuator analyzes the incoming message in terms of physical characteristics, language, and meaning
• In Treisman's model, both attended and unattended messages pass through the attenuator, with the attended message emerging at full strength and the unattended messages being attenuated
• Treisman's model allows for the use of language and meaning to separate messages
• In the "Dear Aunt Jane" experiment, participants reported hearing the message "Dear Aunt Jane," even though the message presented to the attended ear was "Dear 7 Jane"
• Treisman's model suggests that the analysis of the message proceeds only as far as necessary to identify the attended message
• The model proposes that once the attended and unattended messages have been identified, the attended message emerges at full strength, while the unattended messages are weaker but still present