Attention
Failure to attend

Inattentional blindness was first introduced in 1998 by Arien Mack and Irvic Rock. Their studies show that when people are focused on specific stimuli, they often miss other stimuli that are clearly present. Though actual blindness is not occurring here, the blindness that happens is due to the perceptual load of what is being attended to. Based on the experiment performed by Mack and Rock, Ula Finch and Nilli Lavie tested participants with a perceptual task. They presented subjects with a cross, one arm being longer than the other, for 5 trials. On the sixth trial, a white square was added to the top left of the screen. The results conclude that out of 10 participants, only 2 (20%) actually saw the square. This would suggest that when a higher focus was attended to the length of the crossed arms, the more likely someone would altogether miss an object that was in plain sight.

Change blindness was first tested by Rensink and coworkers in 1997. Their studies show that people have difficulty detecting changes from scene to scene due to the intense focus on one thing, or lack of attention overall. This was tested by Rensink through a presentation of a picture, and then a blank field, and then the same picture but with an item missing. The results showed that the pictures had to be alternated back and forth a good number of times for participants to notice the difference. This idea is greatly portrayed in films that have continuity errors. Many people do not pick up on differences when in reality, the changes tend to be significant.
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