Describe three (3) early models of attention. What are the important differences between them? What types of experiments have identified strengths and weaknesses in these models?

Broadbent’s Filter Model of (Early) Selective Attention

  • Simultaneously presented information has parallel access to a sensory buffer
  • There is a selective filter that operates on input information on the basis of physical characteristics alone – thus it is an early selection model
  • A limited capacity processor then selects inputs on the basis of basis of their meaning (this is early)
  • The filter selects one channel after sensory analysis of the physical features of the stimulus (tone of voice, etc)
  • All other information decays rapidly

Experiments used to Identify Strengths and Weaknesses

  • Strengths:
    • Dichotic Listening Task – sensory information can be attended to early
    • Shadowing Tasks – attention is insensitive to information about the meaning of a message (input) but is sensitive to changes in the sensory properties of the input
    • Split-Span Procedure – sensory organs act as channels of information
  • Weaknesses:
    • Stroop task (1935) – showed shape and colour of input do interact
    • Triesman found that in the shadowing task, participants sometimes said a word from the unattended channel – phenomena called ‘breakthrough’ – incompatible with the filter model because the unattended channel is ‘turned off’ in that type of model

Triesman’s Attenuation Theory

  • Triesman argued that the selective filter attenuates unattended input rather than turning off the channel – input passes on information in a much weakened form
  • How does the filter operate on meaning? – input stimuli that are biologically relevant or emotionally important are pre-set and so not attenuated thus allowing for the breakthrough effect

Experiments used to Identify Strengths and Weaknesses

 Strengths:

–     Cocktail party phenomena (Cherry, 1953) – although not aware of other conversations, we may hear some noticeable information emerge form the background (like our name)

Deutsch and Deutsch Late Selection Theory

  • Deutsch and Deutsch argued that all stimuli are analysed at the semantic level and only some inputs are selected for response
  • Non-attended or non-shadowed inputs will be attended to only if their relevance exceeds the relevance of attended or shadowed inputs
  • An unattended message may be recognised but the output of this recognition or semantic process may not pass into awareness
  • This allows for subliminal perception of inputs, that is processing of inputs with no conscious awareness

Experiments used to Identify Strengths and Weaknesses

 Strengths:

  • Subliminal recognition (Lewis, 1970) – words in both channels are analysed for meaning and were perhaps compared but not consciously
  • Unlikely all information is processed as we do filter irrelevant information and forget inputs rapidly

Distinguish between divided and selective (focused) attention. Compare and contrast the features of focused endogenous and exogenous visual attention. Describe the effect of perceptual versus cognitive load on focused attention

Focused and Divided Attention

  • Focused/Selective Attention – a situation in which individuals try to attend to only one source of information while ignoring other stimuli
  • Divided Attention/Multitasking – a situation in which two tasks are performed at the same time

Endogenous and Exogenous Attention Systems

  • Endogenous – active of focal attention, voluntary and goal-directed, controlled by topdown processes such as goals and intentions
  • Exogenous – passive or automatic attention controlled by data driven process working on sensory information

–     Things that grab your attention no matter what or depending on the context

Perceptual Load Theory (Lavie, 1995)

  • Allows selection to occur at multiple levels
    • Everyone has limited attentional capacity
    • The amount of attention allocated to the main task depends on perceptual load
    • Any spare capacity beyond that taken by the high priority relevant stimuli is automatically redirected to the irrelevant stimuli
  • Effect of perceptual and cognitive load on focused attention
    • When perceptual load is low, attention “wanders”
    • When perceptual load is high, attention is focused
    • When cognitive load is high (it is a more cognitively challenged task), it is harder to keep attention focused
    • It seems to take cognitive effort to focus attention

List the factors that determine how well we operate in dual task conditions. Describe, with examples, the four major dimensions of multiple resource theory and how they are used to explain dual task performance

Determining Factors in Dual Task Conditions

  • The degree of similarity of the two tasks
  • Similar stimulus modality
  • Similar response modality
  • Practice
  • Serial or parallel processing
    • Serial processing – switching attention backwards and forwards between the 2 tasks with only one task being attended to and processed at any given moment
    • Parallel processing – attending to (and processing) both tasks at the same time

Multiple Resource Theory (Wickens, 1980)

  • Processing stages
  • Processing codes
  • Modalities
  • Response type

Automatic Processing

 Controlled processes

  • Limited capacity
  • Require attention
  • Can be used flexibly in changing circumstances  Automatic processes
  • Suffer no capacity limitations
  • Do not require attention
  • Very hard to modify once learned