The Superhuman Mind

Cases of extraordinary mental ability

Just How Blind Are You?

Inattentional blindness makes the conspicuous inconspicuous

If a fire broke out, how quickly could you locate the nearest fire extinguisher? Would you be able to recall its location from memory or would you have to search for it? The U.S. Occupational Health and Safety Organization requires fire extinguishers to be located conspicuously within 75 feet of employees so these devices quickly can be found. But conspicuous location and close proximity might not be enough for these objects to make it into your memory.

While taking a class on building safety at the University of California Los Angeles, Keith Holyoak was among several participants unable to recall the location of the nearest fire extinguisher. After he was instructed search for its location, he was startled to find the fire extinguisher hung outside his office, literally right next to the door he had entered for over 25 years. This realization inspired Holyoak and colleagues to conduct a study on inattentional blindness, a phenomena that occurs when one does not notice a stimulus within plain sight. Inattentional blindness has been shown to occur in many different settings. In one study, researchers showed that subjects asked to perform a counting test while watching a video consistently fail to notice a gorilla walking across the screen (try it out on your friends). Other studies have shown that subjects often have trouble noticing changes to a scene even if the change occurs to an object of focus within the previous scene.

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Authors of the present study recruited students, faculty and staff who worked in the UCLA Psychology Department, located in a building with six fire extinguishers per floor, with no office located further than 25 feet from the nearest fire extinguisher. Participants were asked to describe the location of the fire extinguisher closest to their offices within the department. Participants were also asked to rate their level of confidence in providing a correct answer. While 39% could give the location of at least one fire extinguisher within the building, only 24% of participants knew the location of the nearest one. Confidence levels were very low across the board. However, 92% of participants could find the nearest fire extinguisher within five seconds of leaving their office. Interestingly, the authors found no correlation between years worked in the department and ability to recall fire extinguisher location. It appears that people who potentially had passed the conspicuous red objects literally hundreds of times formed no better memories of the fire extinguishers than those who had many less opportunities to do so.

The study brings to light an important distinction between seeing an object and noticing an object. While many objects might cross into a subject’s field of vision where it is seen, the same subject may not notice it. In the fire extinguisher study, 22% of participants reported seeing the location before but couldn’t remember the object being there. However, once participants noticed the fire extinguishers, they were able to remember the location later on. Two months later participants were again asked to describe the location of the previously located fire extinguisher. This time, all participants could recall the location of the nearest one.

Like other studies on inattentional blindness, this one indicates that merely seeing or hearing something doesn’t enhance memory. Many of the participants who answered correctly reported specific memories of the fire extinguishers due to some event that related to them, having completed a safety course or having viewed them many times. This case is particularly striking because many other participants managed to avoid having their attention captured by a highly conspicuous object (after all, fire extinguishers are painted red because the color is thought to stick out).

These findings might have important implications for how we understand memory, particularly of objects that may be of great importance to us later on. Subjects were very good at finding the fire extinguisher when instructed to search for it, indicating that the devices are conspicuous enough to capture attention in goal-directed action. But finding a fire extinguisher during a fire could be much more difficult. While participants in this task benefitted from clear lines of sight to the fire extinguishers, the ability to find the fire extinguisher could be very different in a smoke-filled room. Individuals therefore may need to recall the location of fire extinguishers from memory in the event of an actual fire. The present study indicates that and object’s location can be recalled from memory for at least two months after initial recognition. Further research could focus on the best method of getting the average subject to store object location for longer periods of time. 

Kristian Marlow is a graduate student at the University of Missouri-St. Louis and a member of the St. Louis Synesthesia Lab.

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