Have you ever seen the image of a vase and two faces? This image doesn’t change, but upon first glance, we are more likely to see one image or the other. It’s only after train our brain to see the other image, or someone tells us to see this image, does it appear.
Or, let’s say you see the image below. If I were to ask you if you saw the man in the image, you would probably recognize the man’s face right away. But if I had presented this image to you and asked you to identify the rat in the image, your perception of the drawing would have been totally different.
In fact, based on whether or not the image was placed in a pile of animals or faces, participants in a 1961 study were more likely to see the image of the rat or the man.
This study is just one of many to support the idea of top-down processing. If you watched my last video, you know that top-down processing is a theory that opposes bottom-up processing, which was proposed by James J. Gibson.
The theory of top-down process was developed just a few years later, and is often explained side by side with bottom-up processing to round out the overarching theories on visual perception. In this video, I will be discussing top-down processing and how it explains the way we perceive the world around us.
What is Top Down Processing?
Top Down Processing is idea that our brains forms an idea of a big picture first from previous knowledge, and then breaks it down into more detailed specific information.
There is a lot of stimuli to take in at any given moment. It can seem utterly exhausting to break down every sight, sound, and feeling that we experience and analyze them to build our perception of the world. After all, we have gathered so much data and built up so many schema over the years that we could basically recreate the things that we know best just by thinking of them.
That’s basically what we’re doing when we perceive the world with top-down processing. We begin the process of perceiving the world around us by pulling from our perceptual set. This perceptual set contains experiences, expectations, and emotions. It allows us to quickly form an opinion or judgement on what we are seeing and experiencing based on what we have seen and learned in the past.
This is a more holistic way of looking at visual perception. We start by perceiving the whole object. In the Rat-Man example, we start our analysis by seeing the rat or the man based on the context of the situation or our expectations. Then, we begin to break down the visual stimuli and see that yes, this could be a rat or a man or a different drawing altogether.
The man responsible for developing this take on visual perception theory is British psychologist Richard Gregory. Gregory did not coin the term “top-down processing” or create this idea from scratch. His theory was mainly realized as a response to Gibson, and he credits Hermann von Helmholtz as the father of this theory.
Gregory proposed that while the eye does take in a lot of stimuli, most of it is lost by the time it reaches the brain. So we can’t possibly construct our entire perception of what’s in front of us in the direct way that Gibson proposed.
In order to “fill in the blanks,” the brain uses hypotheses based on what it expects and what it already knows about the world. Of course, hypotheses are not always true. As we gather more details and focus more on different elements of what we are seeing, we could discover that our initial hypotheses aren’t true. Hence, we realize the rat isn’t just a rat or the man isn’t just the man.
Example 1: B vs. 13
In my article about Bottom Up Processing, I used an example to show how top-down processing worked vs. bottom-up processing. I’ll repeat the example just to refresh your memory, but I’ll start by explaining how this example works using top-down processing.
Let’s say you are reading a piece of paper. You see the number 11, the number 12, and then what appears to be the number 13. Or, at least that’s what your brain says when you come across it. After a closer look, you realize you are looking at a capital B, but your brain chose a number first due to the context of what you were seeing.
If you are using bottom-up processing, you probably wouldn’t have made the mistake of seeing the 13 first. You would have simply taken in the stimuli for what it was and then analyzed whether or not it was a B, a 13, another symbol, etc.
Example 2: Jumbled Letters Still Make Sense
Have you ever seen the passage in which every word is spelled wrong, but the first and last letter are correct? Most likely, you can read the whole passage without struggling. The individual words themselves make no sense, but reading the word as a whole, and within the context of the larger sentence, is a breeze.
While this passage was not written in order to support top-down processing, it could serve as evidence to prove that we can process words as a whole rather than letting the stimuli itself lead the way in reading and understanding a piece of text.
Example 3: Reading Misspelled Words or Bad Handwriting Is Easier When Reading a Whole Sentence
There’s a picture that floats around social media or falls into your email inbox every now and again. It shows a paragraph made of misspelled words. The letters are rearranged so that the first and last letter are correct, but everything else is out of place. Somehow, you can still read the entire paragraph!
This is top down processing in action. If you were to see any of the words in the paragraph separately, you would probably have a harder time understanding what the word is saying. But when it’s strung together in a sentence, your brain understands the context and easily comprehends the word.
Example 4: The Stroop Effect
You might have heard about this little challenge before. Let’s say you see a list of colors: red, black, etc. Each of the words is written in a different color that doesn’t match the word. “Red” might be written in black, etc. When asked to identify the colors of the words rather than the word itself, people may have a hard time. It’s easy for the brain to read the word.
This is an example of top-down processing because we understand and process the concept of reading the words in front of us rather than identifying the color. We automatically process the word, causing the delay when we are trying to do the different task. You can learn more about the Stroop Effect Here.
Example 5: Phonemic Restoration
Top-down processing helps us to “fill in the blanks” and give our senses less to do. A majority of the things that we see and hear are “filled in.” Once we’ve grasped the concept of what we’re seeing, hearing, smelling, etc., the brain does the rest.
This causes an exciting phenomenon called phonemic restoration. When speech signals are replaced with certain sounds, our brains can fill in the blanks and “hear” what is being said. White noise, for example, could disrupt small pieces of speech signals and would go completely unnoticed. You can hear examples of phonemic restoration online. As white or pink noise starts to fill in the gaps between the person’s speech, it becomes more coherent.
Phonemic restoration is very useful for humans. Without it, we would have a hard time hearing everything and would require a more quiet environment in order to have a chat.
Example 6: Seeing a Pile of Produce That Don’t Have Any Bruises
Top-down processing doesn’t just allow us to fill in the blanks when we are listening to people. We also fill in the blanks with our eyes. This means that knowledge of top-down processing can be used to manipulate an image or idea.
Let’s say you are arranging fruit at a grocery store. Only one side of the fruit has some bruises, but you really need to sell the fruit. What side do you have facing the customers?
You could arrange the produce so that the good-looking side is facing the customers. When the customers see the fruit, they “fill in the blanks.” They don’t need to see the back of the fruit - they know it’s there. In this case, unfortunately, they just won’t know that the back of the fruit is covered in bruises. Only if they pick it up and inspect it will they know what’s on the other side.
While it appears that top-down and bottom-up processing are two different ways to view the world, many argue that we use a combination of both to see, hear, and understand what is happening around us. Top-down processing allows us to apply patterns and past knowledge to understand what is happening faster. But taking in smaller details allow us to refine what we are seeing and possibly see things in new ways.