Attention as Information Processing

• Lecture Notes 2 is on Attention
• Some questions to consider: Is it possible to focus attention on one thing? Under what conditions can we pay attention to multiple things? Is it true that we don't pay attention to the environment? How does attention support perception?

Attention as Information Processing

• Selective attention involves focusing on one message and ignoring others.
• Dichotic listening is an early selection process.
• It involves presenting one message to the left ear and a different one to the right.
• Shadowing involves repeating a message out loud as it is heard.
• Used with dichotic listening to focus attention on the attended message.

Broadbent's Filter Model of Attention

• Donald Broadbent's (1958) model includes these stages:
  • Sensory Memory: Holds incoming information briefly.
  • Filter: Identifies the attended message based on physical characteristics and lets it pass through.
  • Detector: Determines high-level characteristics/meaning.

Early-Selection Models

• Cherry (1953) found participants couldn't report the content of the unattended ear when using shadowing.

Problems with Early Selection Models

• Moray's (1959) experiment had participants shadow a message from one ear.
• When the listener's name was presented to the unattended ear, about a third of participants noticed; this is known as the cocktail party effect.
• Gray and Weddeburn (1960) had participants shadow a message from the left ear and report hearing "Dear Aunt Jane" even though it jumped between ears.

Modifying Broadbent's Model: More Early Selection Models

• Anne Treisman's model of selective attention has selection occurring in two stages:

  • Attenuator analyzes incoming information to identify the attended message, passing at full strength while reducing unattended message strength.
  • Dictionary unit contains stored words/thresholds for activation.

• The dictionary unit of Treisman's model has words with thresholds; a person's name has a low threshold, so it will be easily detected.

A Late Selection Model

• Models propose that incoming information is processed to the level of meaning before selecting the message.
• Early selection is based on physical characteristics; late selection is based on meaning.
• Treisman's attenuation is in-between, using meaning, physical characteristics, or both.

Processing Capacity and Perceptual Load

• Processing capacity is the amount of handleable information input, which limits information processing.
• Perceptual load relates to task difficulty; low-load tasks use less processing capacity than high-load.
• Load theory of attention says the ability to ignore irrelevant stimuli depends on the task's load; high-load tasks have less distraction.

Flanker-Compatibility Task

• Participants respond to a target stimulus flanked by distractor stimuli.
• Interference indicates distractor processing.

Flanker Compatibility Tasks Outcomes

• Compatible flankers (like B) result in a fast response to A.
• Incompatible flankers (like C) result in the slowest response time to A.
• Neutral flankers (like X) result in an intermediate response speed.
• In Forster and Lavie's (2008) experiment reaction time for an easy condition where the target is with small ‘o's, is generally faster than the reaction time for the hard condition, where the target is accompanied by other letters.

Stroop Effect

• It is the ability to ignore task-irrelevant stimuli relative to cognitive load and stimuli power.
• J. R. Stroop studied it, where people respond to one stimulus aspect, ignoring another.
• People find it difficult when the ink color differs from the word name.
• Reading is automatic, so it's hard not to read words.

Directing Attention by Scanning a Scene

• Scanning a Scene with Eye Movements
  • Saccadic eye movements go from one fixation point to another.
  • Fixation is pausing the eyes while observing.
• Scanning Based on Stimulus Salience
  • Bottom-up factors determine attention, like color, contrast, and orientation.
  • A saliency map indicates the stimulus salience of areas and objects.
• Scanning Based on Cognitive Factors
  • Scene schemas use knowledge about what is likely in a scene.

Scanning Based on Task Demands

• Eye trackers measure where people look (fixate) and how their eyes move.

Outcomes of Attention

• Attention Improves Our Ability to Respond to a Location
  • Posner et al. (1978) found information processing is more effective where attention is directed.
  • Precueing uses a cue to help participants carry out a task; has been used to direct visual attention.
  • Posner et al.'s (1978) experiment tested valid (245 ms) and invalid (305 ms) trials; average results determined that valid trials had a faster reaction time than invalid trials.
• Attention Improves Our Ability to Respond to Objects
  • Attention can enhance our response to objects.
  • When visual attention directs to one place on an object, it enhances the object.
  • In Egly and coworkers' (1994) experiment, a cue signal appears then turns off, and a position flashes which helps the participant determine if the cue signal had appeared at that position or a different position.
• Same-Object Advantage
  • Occurs when attention spreads throughout an object; attention to one place facilitates processing elsewhere on the object.
• Attention Affects Perception
  • Experiments show attended objects appear bigger, faster, richly colored, higher in contrast.
• Attention Affects Physiological Responding
  • Covert attention increases activity where the brain corresponds to that location.
  • Datta and DeYoe's (2009) experiment had people direct attention to different areas on a display while keeping their eyes fixed; activity showed where participants attended.
  • Attention to specific categories increases the brain area devoted to it.

Divided Attention

• An individual is able to to attend to, or carry out, two or more different tasks simultaneously.
• Divided Attention Can Be Achieved With Practice
  • Is processing that occurs automatically, intending to use little cognitive resources & associated with easy tasks.
• Divided Attention Becomes More Difficult When Tasks Are Harder
  • It becomes nearly impossible if there is a struggle to find one specific target from the rest.

Divided attention and Automatic processing

• Schneider and Shiffrin's (1977) experiment
  • Sample stimuli
  • Letters内 are more difficult to find.
  • Numbers内 are more automatic & easy

What Happens When We Don't Attend?

• Inattentional Blindness is not noticing something even though it is in clear view, usually from failure to pay attention.
• Change Blindness is difficulty in detecting changes in similar and/or different scenes.
• Continuity Errors are changes that occur from one scene to another that do not match the previous event.

Attention and Experiencing a Coherent World

• The Binding Problem explains how an object's individual features become bound together.
• Feature Integration Theory is an approach developed by Anne Treisman that proposes that object perception occurs in a sequence of stages in which features combine to result in perception of an object.
• Preattentive Stage means an object is analyzed into its features.
• Focused Attention Stage is where the combination of certain features leads to perception of an object.

Illusory Conjunctions

• Features from different objects are inappropriately combined.
• According to Treisman, illusory conjunctions occur because, at the beginning, each feature exists independently of the others.
• Visual feature performance can eliminate it

Visual Search

• Occurs when looking for one stimulus or object among other stimuli.
• Feature Search: Searching among distractors for a target that highlights only one feature
• Conjunction Search: Searching for objects that have more than 2 features.