The truth is, the human brain is somewhat limited when it comes to processing visual images.
Not everything we see with our eyes actually registers with our brains. There is simply too much visual information to completely process every second; therefore, our brain processes just a fraction of what we see.
However, if something changes, flashes, or skirts across our vision, we automatically give it our full attention. It is this hypersensitivity to movement that has led many people to be overconfident in their ability to observe things.
In reality, people are often surprised at how blind they can actually be in a given situation.
By definition, change blindness is the failure to notice a visual change in our field of vision.
Two Views – Same Phenomenon
Previous research has uncovered two theories to suggest how humans view things. One is called the top down approach; the other is the bottom up approach. The top down theory suggests that our brain puts things into context as we see them.
For example, if you are told to look to find a computer in an office, you would automatically look at the desk, since that is where your brain expects a computer to sit. You would not immediately look at a window or the ceiling of the office – your brain has already learned that the computer would most likely not be on the ceiling.
The bottom up theory focuses on the things in the field of vision that stand out. These two theories are perhaps the more basic elements of how our brain deals with the visual images that it is bombarded with every day.
A Little Bit of Truth in Each
Both of these theories are used at different times in different settings. Depending on the desired outcome, the top down process is used to look through the scene to see if there is anything of interest. Then our bottom up way of thinking takes over to notice the thing that suddenly stands out.
When your brain uses one process, the other has to be set aside.
This simple fact that it is difficult to do two things at once means that details can be missed, or changes overlooked, regardless of how acute you think your attention to detail has been developed.
The human brain allocates our resources as needed to different tasks, but we can’t do it all, all the time.
We also cannot explain everything all of the time, and that is why we wanted to share an awesome related video on the concept of change blindness and a test you can take to determine your own cognitive abilities.
This video is great – from the observer’s point of view (us watching the video) it seems so shocking that the people giving directions don’t notice the switch!
And here is a really great test for you to take as well, and make sure to leave a comment and tell us how you did…this is a test on your ability to notice changes in a series of photos – I definitely did not do as well as I thought I would have… Once again, writing these articles demonstrates we all have a lot to learn and a lot of brain power to continue to harness and develop.
Verma, Milan, and Peter W. McOwen. “A Semi-automated Approach to Balancing of Bottom-up Salience for Predicting Change Detection Performance.” Journal of Vision. June 4, 2010. Volume 10, number 6, article 3. Full text: http://www.journalofvision.org/content/10/6/3.full