I was watching an episode of Air Crash Investigation the other day and investigators stated that the cause of a fatal aeroplane crash was change blindness.
My ears pricked up. I thought I’d heard of every psychological trait in the book, but I’d never come across this one. What on earth was it and how could it have caused two experienced pilots to make terrible errors in the cockpit that lead to the deaths of their passengers?
I had to find out. So what are the basics behind change blindness?
What Is Change Blindness?
Basically, it is when something we are looking at changes without us noticing. But how can it happen? We all like to think that we have a keen eye for what’s going on around us. We are natural observers. People watchers. We see things. We notice stuff. If something has changed, we can tell.
Well, actually, that’s not quite true. Studies show that if we are distracted for long enough, then our focus fails. Even more surprisingly, the change can be huge and we still won’t see it. So how does it happen?
“Change blindness is a failure to detect that an object has moved or disappeared and is the opposite of change detection.” Eysenck and Keane
This infamous study has been replicated many different times. In the original one, participants watched a video of six people and had to count how many times the ones wearing white tee-shirts passed a basketball to each other.
During this time, a woman entered the scene in a gorilla suit, stared at the camera, banged on her chest then walked away. Half the participants didn’t see the gorilla.
It appears that if we focus on one task we cannot see other things.
Focusing our Attention Limits our Resources
Our brains can only manage so much information at a time. Therefore, it has to prioritise and limit what it deems to be unnecessary.
This is why we can’t feel the clothes we are wearing, or as you are reading these words now, you are not aware of noises from outside. Of course, now I’ve mentioned them you are now beginning to pay them more attention.
However, our attention span is limited. This means whatever we focus on has to be carefully chosen. Typically, that one thing we do pay attention to gets all our attention. In fact, to the detriment of everything else. As a result, we miss out on large swathes of detail because of our laser-like focus on the one area.
In this study, a researcher talks to a participant. While they are talking two men walk between them carrying a door. The door blocks the view of the researcher and the participant.
While this is happening, the researcher swaps places with one of the men carrying the door and once the door had passed then continues chatting to the participant as if nothing untoward has happened. Out of 15 participants, only 7 noticed the change.
If something blocks our view for just a few seconds, it is enough to distract us.
We use our past experiences to fill in the gaps
If we can’t see for a few moments our brain fills in the gap for us. Life flows, it doesn’t stop and start in jerks and jolts. This is our brain taking the shortest cut necessary in order to keep us surviving and performing quickly in our ever-changing world.
In all our past experiences, we haven’t come across someone changing into someone else so we presume it won’t happen today. We simply don’t expect to see a different person when the door has passed us. It doesn’t make sense so we don’t even entertain it as a possibility.
Losing Sight of a Person
In this study, participants watched a video of a student lounge. One female student leaves the room but has left her bag behind. Actor A appears and steals money from her bag. She leaves the room by turning a corner and walking out through the exit.
In the second scenario, Actor A turns the corner but then is replaced by Actor B (the viewers don’t see the replacing) they just see her exit. When 374 participants watched the change film, only 4.5% noticed the actor had changed.
If we lose our visual reference for a few seconds, we assume it will be the same when it reappears.
If the change doesn’t make sense to us, it is difficult to see
Changes are usually drastic, sudden, they catch our attention. Just think about sirens on emergency vehicles or someone acting suspiciously. We have a tendency to see things that change because they are usually moving in some way. They switch from a static nature to a mobile one.
But people don’t change into other people. Gorillas don’t just appear out of nowhere. That’s why we miss things that are out of the ordinary. We just don’t expect people to change into other people.
How to Reduce the Effects of Change Blindness
- Individuals are more likely to make this sort of mistake than people in groups.
- Changes are easier to stop when objects are produced holistically. For example, a whole face rather than just the facial features.
- Changes in the foreground are detected more easily than changes in the background.
- Experts are more likely to notice changes in their own field of study.
- Visual cues can help bring the focus back onto the object of attention.
As for the aeroplane in the programme? Eastern Airlines was due to land in Florida when a small bulb in the landing nosegear light failed in the cockpit. Despite the alarm warning, the pilots spent so much time trying to get it to work they failed to notice their altitude was seriously low until it was too late. They crashed into the Everglades. Tragically, 96 people died.
It’s not likely that we are going to be faced with the task of counting a basketball and miss a woman prancing around in a gorilla suit every day. But as the air crash programme has shown, this phenomenon can have devastating effects.
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