Simons and Chabris

• background


  • inattentional blindness: the failure to see an even or object that is in your field of vision because you are so focused on other elements of what you can see
  • Mack and Rock used computer-based dynamic research to measure visual inattention
  • Neisser used to video based dynamic research to measure sustained inattentional blindness
• aims


  • to investigate if inattentional blindness would be more likely if the unexpected event was similar to the attended event
  • to find out if particularly unusual events would.be more likely to be seen
  • to investigate whether participants would have trouble noticing the unexpected event when the task they were given was more difficult
  • to investigate the effect of the 'transparent' video and compare if the same level of blindness would occur in a more realistic video
• procedure


  • participants were instructed to focus on either the team in black shirts or the team in white shirts
  • the unexpected event was either a woman carrying an umbrella or a gorilla
  • participants were asked to mentally count the number of passes that the team made or to keep two separate counts of the number of bounce passes and the number of aerial passes made by the players in their team
  • the video participants watched was an 'opaque' video unlike Neissers 'transparent' effect or a 'transparent video
• results 


  • overall 54% noticed the unexpected event and 46% did not
  • 67% of participants noticed the unexpected event in the opaque condition, compared to only 42% in the transparent condition
  • more participants noticed the unexpected event in the easy condition compared to the hard condition, 64% vs 45%
• conclusions 


  • inattentional blindness occurs in dynamic event that are sustained, lasting more than 5 seconds
  • the phenomenon of intentional bias cannot be accounted for as simply a response to the transparent video
  • the findings of a computer-based study can be generalised to situations close to real-life experiences
  • objects can pass through our central field of vision and still not be seen if they are not specifically attended to
• sample


  • 228 observers
  • undergraduate students at Harvard university
• links to the area

  • provides evidence of inattentional blindness
  • participants often failed to notice the woman in the gorilla costume or carrying an open umbrella as they were focused on another task
  • this is even more likely to be missed if the task they are attending to is more difficult