What you see is what you get - or is it?

Take a look at the picture below. Which of the horizontal lines is longer?



This picture is the famous Ponzo Illusion. The lines are the same length. How did you respond to that question? Did you

1. trust what you saw and say that the top line was longer
2. think back to a similar illusion that you've seen in the past and assume that the lines were the same
3. measure the lines to find out for sure
4. consider alternative ways to look at and make sense of the image

The first two are probably representative of how we approach many things. We trust our assumptions and senses without verification. That can get us in trouble. The second two represent good critical thinking.

This illusion illustrates a very simple idea: our senses may not be as accurate as they seem. We often rely heavily on what we sense – after all “seeing is believing”, right? It's reasonable to trust our sense. They are a deeply ingrained part of who we are. But, as the illusion demonstrates, senses can deceive us.

Actually, it’s not our senses that are deceiving us, it is our brain. Senses are just input devices just like microphones or video cameras. It's the way that those inputs get processed which creates problems. What we “see” isn't just a simple record of the image that entered our eye. It is influenced by our past experiences and what we’ve seen before. A recent research study showed that when an image enters your eye, two parts of your brain become active. The first is the part responsible for generating the image. The second is the part assocaited with your memory. That's why family resemblances are often more obvious to strangers than they are to family members. Strangers just see the actual features. Family members "see" all of the stories, experiences, and meaning behind those features which makes each family member appear much more unique.

It’s easy to feel certain about our perceptions because they often seems so real. Those lines in the illusion really look different, don’t they? But don't be fooled. Our brain dictates everything that we perceive whether it be through sights, sounds, smells, or even thoughts.

Recent discoveries in neuroscience have shown that by the time we become conscious and aware of anything, our brain has already applied several layers of “meaning” to it. Sometimes that meaning is real, other times, like with this illusion, our brains distort it. And, we can’t stop it. Look at the lines again. You know that they are the same yet you cannot stop your brain from making you see them as different.

So, the next time you feel certain about something that you are seeing, hearing, or thinking, remember that it might just be a very convincing illusion created by your brain. You might want to turn to some external source to validate your perceptions.