simon & chabris - updated

• what does the research suggest?

  unless we pay close attention, we can miss even the most conspicuous events
• what is inattentional blindness?

  when attention is diverted to another object or task and observers often fail to perceive an unexpected object, even if it occurs at the point of fixation
• background context - who composed a divided-visual-attention task?

  Neisser et al (1979)
• what happened in the task composed by Neisser et al?

  superimposed videotapes were watched by observers of two teams playing pass with a ball, each person was asked to attend one team and press a button when one of them made a pass.

  woman carrying an umbrella walked across the screen
• how many observers saw the woman in Neisser et al?

  6 out of 28
• what happened when observers just watched the screen in Neisser et al?


  always noticed the woman with the umbrella
• what is inattentional amnesia?

  unexpected event is perceived consciously but then immediately forgotten
• who proposed inattentional amnesia?

  Wolfe (1999)
• what was the aim in simon & chabris?

  to examine variables that affect inattentional blindness in naturalistic, dynamic events

  • role of superimposition compared to live events
  • measure impact of task difficulty
  • if unusualness of unexpected event had an impact on detection rates
• what was the research design?

  laboratory experiment, independent measures design
• what was the sample?

  228 ppts, mostly undergraduate students offered a chocolate bar or a one off payment
• what was the sample design?

  volunteer sampling
• how many data was used?

  192 - 36 were discarded
• why was data discarded?

  1. knew about the experiment/similar - 14
  2. lost count of passes - 9
  3. passes were inaccurately recorded - 7
  4. answers not clearly interpreted - 5
  5. ppt's total pass count was more than three standard deviations from the average - 1
• what was the independent variables?

  unusualness of event - umbrella or gorilla

  style of video - transparent or opaque

  team colour - black or white

  task difficulty - easy or hard
• what was the dependent variable?

  number of participants in each of the conditions who noticed the unexpected event