While you read this blog, keep in mind a few things. Note that there are 2 main topics I want you to understand and try to realize in the video: the optical illusion occurring with the nose sticking out, making it seem as if there are two faces and notice the top down processing happening in your brain while you watch this video. Do not be warned if you need to blink a few times while the head spins, it gets a little tricky to stay focused on this optical illusion!
As learned in class, Top down processing is essentially our brains taking the information that we are seeing and making conclusions based on previous experiences. We have that background knowledge to influence our perception of what we are focusing on. By having this existing knowledge in our mind, we are making these educated guesses or assumptions, which help lead to the conclusion on what something actually is, or says. A perfect example that I like to think of is, when you are reading a sign on the street, but it is missing some letters, you are used to seeing that sign in other places while you drive, so you can come to the conclusion of what it says based on your previous knowledge!
I have provided you with an optical illusion (below) and it is a mask that has a face on one side, but then it is hollow in the back. In this video, the mask will spin in a slow, complete circle. As this mask spins, you will start to notice the indent in the mask on the backside. We know that there is not a face on the other side, but we also know what faces are supposed to look like in real life. We know that everyone has eyes, a nose, and a mouth. One thing that I noticed in this video is that the nose looked like it was sticking out on the hollow side, that is the optic illusion that the psychologist, Richard Gregory wanted us to focus on. “Perception is a constructive process which relies on top-down processing. Stimulus information from our environment is frequently ambiguous so to interpret it, we require higher cognitive information either from past experiences or stored knowledge in order to makes inferences about what we perceive. Helmholtz called it the ‘likelihood principle’.” (Simply Psychology)
After reading what he had to say about optical illusions and top down processing we can understand what is happening here. Since we know that a nose is supposed to stick out, our mind is reconstructing a face on the other side, which defines top down processing.
I believe that this example will really shape how we see optical illusions, since we now know what exactly is going on in our mind. I think it is amazing that our brain can create images based on prior knowledge and experiences that we have either learned or have gone through. I hope you all get to watch this and experience this compelling argument for top down processing in this optic illusion!!