Selective Attention İlmiye.ozreis@emu.edu.tr

Stages of Cognitive Processing

Attention: Active & Passive Attention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. William James Active attention Controlled by the individual’s goals and expectations. Passive attention Controlled by external stimuli such as a loud noise.

Attention Attention Divided Attention Task Similarity Task Difficulty Practice Focused Attention Auditory Visual

Types of Attention: Selective (Focused) Attention Presents people with two or more stimulus inputs at the same time and instructs them to respond only to one. Shows us how effectively select certain inputs rather than others. It enables us to study the nature of the selection process and the fate of unattended stimuli.

Types of Attention: Divided Attention Studied by presenting at least two stimulus inputs at the same time but with instructions to attend and respond to all stimulus inputs. Studies of divided attention provide useful information about an individual’s processing limits.

Focused Auditory Attention: Cocktail Party Problem (Cherry, 1953) People are able to follow just one conversation when several people are talking. This ability involves using physical differences to maintain attention to a chosen auditory message: Sex of the speaker, voice intensity, speaker location

Focused Auditory Attention: Dichotic Listening Task Cherry’s Experiment: To examine whether people can follow two tasks concurrently. A dichotic listening task was used People presented with two different messages to both ears and one auditory message has to be shadowed (repeated back out loud).

Focused Auditory Attention: Dichotic Listening Task

Focused Auditory Attention: (Cherry, 1953) Experiment 1 Cherry presented two messages in the same voice to both ears at the same time (eliminated physical differences). Result: Listerners found it very hard to separate the two messages on the basis of meaning alone.

Focused Auditory Attention: (Cherry, 1953) Experiment 2 Participants required to shadow only one message Result: Very little information was extracted from the non attended message. For example, they did not notice a change in langauge. Conclusion: Unattended auditory information receives no processing since there was no memory for the unattended words even when presented 35 times.

Broadbent (1958) Three pairs of digits presented dichotically Three digits were heard one after the other by one ear, at the same time the other three digits were presented to the other ear. It was found that participants choose to recall digits ear by ear rather than pair by pair. Thus, if 496 were presented to the left ear and 852 to the right, recall would be 496852 rather than 489562.

Broadbent’s Theory Two stimuli (messages) presented concurrently gain access in parallel to a sensory buffer. One of the inputs is then allowed through a filter based on its physical characteristics while the other message remains in the buffer for later processing. This filter prevents overloading of the limited capacity mechanism and proceses inputs for its meaning.

Broadbent’s Filter Theory

Discussion Braodbent’s theory accounts for most of Cherry’s findings Unattended information is not processed. Degree of similarity When inputs are similar (words presented to both ears) only one or the shadowed message is recalled When inputs are dissimilar (shadowed auditory message and visual pictures) recall for pictures very good Early studies assumed that there was no processing of the meaning of the unattended message Physical characteristics important to select message.

Discussion In later studies: Gray and Wedderburn (1960): When someones name was mentioned in the unattended message they reported hearing it. Gray and Wedderburn (1960): Found that when ‘6 who there’ is presented to one ear and ‘4 goes 1’ to the other, participants report: who goes there, or 4 6 1. This indicates that information can be processed on meaning and is inconsistent with the filter model.

Treisman (1960) Sometimes participants said a word that was part of the unattended message, although, only observed on 6% of trials. Treisman therefore developed another theory that was more flexibale than broadbent’s theory. In her theory, stimulus analysis starts with physical cues, patterns, words, grammer structure and ends with meaning.

Treisman’s Attenuation Theory Treisman: attention operates like an attenuator An attenuator is a switch that allows for differing amounts of energy to pass through it, i.e., the volume control on the T.V. This model allows for the processing of more than one input at a time. Physical cues determine which stimuli receive more attention and are processed further. The meaning of previously processed messages may also influence the attenuator.

Treisman’s Attenuation Theory

Deutsch and Deutsch (1963) Theory All stimuli are fully analysed with the most important or relevant stimulus determining the response. Complete perceptual analysis of messages to both ears. Only important inputs lead to response. i.e., if two taps are required for the shadowed words and one tap for the non-shadowed words, then shadowed words are more important and will be responded and will be recalled more.

Selective Attention Models

Focused Visual Attention We may attend to: Area or region of space (e.g., looking behind you to identify the source of a sound). A given object or objects.

Location-Based Attention Attention is directed to a region of the visual field. Resembles a spotlight: Everything within a small region of the visual field can be seen clearly but all that is not under the attention spotlight is harder to see. Attention can be increased or decreased in line with task demands. Goal directed behaviour-effort and attention.

Location-Based Attention An endogenous system: Controlled by the participant’s intentions, knowledge, expectations Voluntary, goal directed Top down processing An exogenous system: Automatically shifts attention, when we have unexpected cues e.g., smoke Involuntary, stimulus driven Bottom up processing

Object-Based Attention Visual attention is often directed to objects than region Evidence from Neglect Patients Participants presented with two stimuli (a face and a house), which were overlapping. One was moving while the other was stationary. Participants were instructed to attend to either one of the objects. If attention was locased based, then participants would be attending to both because both stimuli in the same location. Results showed that the objects were attended.

Three Attentional Abilities 1. Disengagement of attention from a given visual stimulus 2. Shifting of attention from one target stimulus to another 3. Enaging or lockıng attention on a new visual stimulus

Visual Search Visual search involves searching for and detecting a specified target within a visual display as rapidly as possible

Feature Integration Theory Rapid parallel process of visual features Serial process of features are combied to form objects Features can be combined by focused attention Feature combination can be influenced by strored knowledge In the absence of focused attention or stored knowledge, features are randomly combined. Illusions

Visual Search Time and Degree of Similarity

Guided Search Theory All basic features receive activation Searching for a red horizontal target, all features that are red and horizontal are activated, the others are deactivated. Attention is then directed to ones that are most activated.

Stroop Effect

Stroop Effect Experiment 1: Experiment 2: The task required participants to read written color names of the words independently of the color of the ink (for example, they would have to read "purple" no matter what the color of its ink was). Experiment 2: Participants were required to say the color of the letters independently of the written word with the second kind of stimulus. If the word "purple" was written in red, they would have to say "red", but not "purple“.

Stroop Effect Results: Naming the color of the word does not take longer when the color of the ink does not match the name of the word color. Naming the color of the ink takes longer when the color of the ink does not match the name of the word color.

Stroop Effect Explanation: Such interference was explained by the automation of reading, where the mind automatically determines the semantic meaning of the word (it reads the word "red" and thinks of the color "red"), and then must intentionally check itself and identify instead the color of the word (the ink is a color other than red), a process that is not automatized.