Attention

• Inattentional blindness

  • A phenomenon demonstrated by the monkey business illusion
  • Highlights the reality that we're less aware of things happening in the world around us than we think
  • Demonstrates how powerful selective attention is
• Selective attention

  • Focus on relevant info and filters irrelevant info out of awareness
  • Demonstrates the limited capacity of attention
• Attention

  The process of selection, where we are able to select a particular object amongst others and subject it to further processing or to act upon it
• Change blindness and inattentional blindness demonstrate we can be looking at something but not selectively attending to it, and not aware of it
• Types of Selective Attention


  • Overt Attention
  • Covert Attention
• Overt Attention

  Turning head or eyes to orient towards a stimulus
• Covert Attention

  Paying attention to one thing while appearing to pay attention to another
• Selective attention = multisensory

  We can selectively attend to visual, auditory, tactile stimuli - and can switch attention between the senses
• Cherry (1953) Experiment to assess covert selective attention: The dichotic listening task

  1. Subjects couldn't detect properties of unattended channel: language used, meaning of the message, content

  2. Subjects did notice: Gender of the voice, Physical attributes
• What does Attention do?

  • Filters out most information
  • Operates at an early stage in processing
• Subjects often notice their own name, or other highly relevant information, on the unattended channel
• Ambiguous sentences in a dichotic listening task (MacKay, 1973)

  1. Attended stream: ambiguous sentence "They were throwing stones at the bank"

  2. Unattended stream: biasing word "river" or "money"

  3. The biasing word had a clear effect on how the sentence was interpreted
• Spotlight Model of Attention (Posner 1980)


  Attention operates like a spotlight, enhancing sensory processing of objects in the spatial location to which it is directed

  • invalid trial = Exogenous attentional cueing effects
  • Valid trial = endogenous attentional cueing effects
• Posner's attentional cueing effects

  • Attention increases efficiency of info processing by influencing sensory & perceptual processing
  • Behavioural effects of cues = caused by neuronal enhancement/suppression in early visual cortical areas - Early selection
  • Attention enhances processing of objects in spatial locations
• Egly et al. (1994)

  1. Used a cuing paradigm to direct the attention of participants to different objects and locations1. Same object, Same location
• Egly et al. (1994) findings:

  • a RT cost (invalid vs valid RT) was smaller for the "Same object, different location" condition compared to the "Different object" condition
• Attentional selection operates on objects, not locations

  • Shows preattentive processing - evidence against early selection
• Recognition

  Detecting the target in the circular array is an X or an N while ignoring the distractor letter off to the side
• Nillie Lavie findings:

  • Distractor had a greater effect on reaction time in the low perceptual load condition
  • Attention = early or late in processing stream depending on overall perceptual load
  • Point at which filtering of irrelevant info occurs depends on the perceptual load of the relevant task
• High Perceptual Load

  • Perceptual capacity = used up by task of trying to find the target - none left for the distractor
  • Support for early selection
• Low Perceptual Load

  • The main task doesn't use up perceptual capacity so can process the distractors
  • Support for late selection.