Surely if I asked you what superpower you would like to have, you would tell me that you would love to be invisible at will. Curiously, achieving this is easier than you might think: sometimes you don’t have to hide in plain sight to be invisible . Who has not listened to a driver who, driving with his eyes fixed on the road, did not see that animal that was standing calmly on the asphalt until it was too late? How is it that we cannot see something that is before our eyes?
That we sometimes go completely unnoticed was made clear in 1995, in an incident involving several Boston police officers and four criminals who had been involved in a shootout. One of the police officers, a plainclothes African-American named Michael Cox, was chasing one of the suspects when another police officer, who had just arrived, mistook him for one of the criminals and began severely beating him. This fact made very clear the racist prejudices that still exist in the United States. But what is striking is that, while the group of (white) policemen were beating Cox , another policeman named Kenny Conley passed by them and, according to what he testified in the subsequent trial, he did not see them. Conley was convicted of perjury and obstruction of justice because it was impossible for the court and jurors not to have seen what was happening.
In 2011, psychologists Christopher Chabris and Daniel Simons asked themselves what no one had done before: What if Conley really did not see the aggression? To verify this, they designed a peculiar experiment: they asked a group of volunteers to run after one of their assistants and count the number of times the hat was touched. At one point along the way, these psychologists had arranged for two men to be beating (simulated) a third. The result was very revealing: in broad daylight more than 40% of the volunteers did not see the fight . When this same experiment was done at night, the percentage rose to 65%. Really poor Conley could not see the beating of Cox.
Blindness from lack of attention
Chabris and Simons had been studying so-called inattentional blindness for more than a decade. Their work became famous when in 1999 they did the gorilla experiment : they asked a group of volunteers to watch a video in which there was a group of people, half wearing a white t-shirt and the other half black. Those in white passed a basketball between them and those in black also did the same. To introduce an added complication point, the players were not standing still, but were constantly moving. The task ahead of the volunteers was to count the number of passes made by those in white shirts.
At the end of the video, the psychologists asked what the number of passes had been (15) and if they had seen anything unusual. Surprisingly, half of those who participated in the experiment did not see a person in a gorilla costume enter from the right side, weave between the players, hit his chest in the center of the scene, and exit from the left side of the screen. ; all this in 9 seconds. A similar result was found when replacing the gorilla with a woman with an open umbrella.
In the opinion of these psychologists, not seeing the gorilla is due to a lack of attention: the subjects were busy performing a complex task -counting ball passes- that the gorilla was literally invisible to their eyes. One of the most surprising implications of this work is that one thing is what is in our visual field and quite another that we are aware of perceiving what is there : depending on what we are paying attention to, we will perceive some things and not others.
This happens in all kinds of situations, including at work. Thus, in July 2013 the journal Psychological Science published an article by a group of psychologists who had tested the observation skills of the 24 radiologists at the prestigious Brigham and Women Hospital in Boston. They had been given five scans, each with five images each, of patients’ lungs and had to search them for signs of possible cancer. But what they did not know is that in some images of one of the five patients they had added the figure of a dancing gorilla . How many saw that gorilla inserted in the images of a lung? Very few: 83% of those specialist doctors did not see it. It’s not because they couldn’t see them, but because their brains were busy with what they were doing: They were looking for cancer nodules, not gorillas.
For his part, Christopher Wickens, a psychologist at the University of Illinois who specializes in aviation issues, has found that devices that project flight information (such as airspeed or altitude) on the windshield of the plane or on the helmet of the pilot are not as good an idea as might be expected. Thus, Wickens has shown that if an aircraft unexpectedly appears in the field of view, the pilot is usually unaware of its presence because he is attentive to the projected data. “We now know that superimposing images on the pilot’s field of view does not guarantee that they will detect what appears in the real world beyond the glass of the plane,” says Wickens.
The concept of blindness due to inattention is relatively recent. It was coined in 1998 by psychologists Arien Mack and Irvin Rock. With it they wanted to show that human beings, when we pay attention to something that happens in front of us, we can not realize other unexpected situations that happen in our field of vision. Mack and Rock found in a series of ingenious experiments some very curious results: we are more likely to detect the presence of unexpected stimuli when they have some meaning , such as our name or a smiley face. And the most interesting thing, that although we are not aware of the presence of these stimuli (such as words suddenly appearing on the screen), they influence us in our actions (in this case, a word completion exercise). Is this an example of subliminal influence?
Reference:
Chabris, C.; Simons, D. (2011) The invisible gorilla, HarperCollins
