Bottom-up processing begins with a real-time stimulus, such as a loud horn blast or the smell of coffee, leading to analysis.
Have you ever wondered how your brain perceives, perceives and interprets incoming data?
One way to make sense of the world is through a psychological strategy called “bottom-up” processing.
This strategy begins outside of us—with external data like a cool breeze, a flickering light, or a car rushing by. Then that sensory information travels to your brain, where it is analyzed.
Bottom-up processing is a psychological strategy first defined by American psychologist James J. Gibson in the 1960s. This process is considered one of the most important ways we understand the world around us.
It’s called “bottom up” because it starts with the external stimulus – like a tree or the smell of cookies – and then relays that sensory information to the brain for analysis.
For example, if you suddenly notice a sweet chocolate smell wafting through the house, you might realize that someone is baking chocolate chip cookies in your house.
You didn’t need any further context or information to determine this – you simply used the sweet smell (the stimulus or the raw data) for your analysis. Her perception required no prior knowledge of anyone baking cookies.
Overall, bottom-up processing involves the following steps:
- Acquisition of new sensory information
- Sensory receptors send signals to the brain
- the brain creates a perception through these signals
A few years after the concept of bottom-up processing emerged, British psychologist Richard Gregory proposed “top-down” processing as a counterpart to bottom-up processing. The two theories are usually taught side by side.
for many years
Bottom-up is a reductionist theory, meaning it begins by observing the most fundamental parts of a concept. The opposite of reductionism is holism theory, which is the theory of top-down processing.
In top-down processing, the brain uses hypotheses or theories to fill in the blanks. So while bottom-up processing relies solely on sensory data, top-down processing starts with the big picture. It also depends on the context, prior knowledge and your expectations.
For example, have you ever read a paragraph where every word is completely misspelled, but you can easily read what’s inside? While the individual words may seem like nonsense, you can use the larger context to figure them out. This is top-down processing.
Here are the key differences between the two strategies:
- Bottom-up processing: starts with the stimulus, travels through the senses and works up to the brain where it is analyzed.
- Processing from top to bottom: is holistic and starts from the big picture. It uses contextual clues, past experiences, expectations, and prior knowledge to arrive at an analysis.
You run out the door to meet a friend for lunch. As you walk to your car, a fresh breeze blows in your face. The sky is dark and you hear thunder. Better grab an umbrella!
In this case, your senses have detected a dark sky, thunder and wind. You quickly analyzed that it’s going to rain and you should grab an umbrella.
B or 13?
“B or 13?” is a commonly used example to demonstrate the difference between bottom-up and top-down processing styles.
Suppose there are two marks on a page. One is a straight up and down line and the other is a line that is curved twice, like two semicircles stacked. There is very little space between the two figures.
With bottom-up processing, you could immediately assume it was a B. You see the shape looks like what you expect a B to be, so assume it’s a B.
However, if the marks are flanked by a 12 on the left and a 14 on the right, you might assume that the mark is a 13. This would use top-down processing as the brain uses contextual cues to determine whether the shape is a B or a 13.
Prosopagnosia (face blindness)
prosopagnosia, or face blindness, is a neurological disorder characterized by the inability to recognize familiar faces. In some cases, people with prosopagnosia cannot recognize their own faces.
Face blindness is a demonstration of bottom-up processing. People with this disorder can recognize facial features, such as brown eyes or a small nose, and know it is a “face.” But they cannot identify who owns them because they are unable to perform top-down processing.
Oliver Sacks, a British neurologist known for successfully treating people with “sleeping sickness,” lived with prosopagnosia.
“Sensation” is the bottom-up process by which our senses—sight, hearing, smell, touch, and taste—receive and transmit external stimuli.
“Perception” is the top-down mechanism our brain uses to organize and interpret data that we place in context.
In bottom-up processing, sensation and perception are essentially the same. In other words, we perceive objects through sensory impressions – and not with our conceptual ideas.
In top-down processing, perception and sensation are separated. First we use context and expectations to create a holistic perception of the world, and then we begin to use sensations to focus on the smaller details.
We use both bottom-up and top-down processing every day to make sense of the world around us.
Bottom-up is a real-time processing strategy that helps you understand your immediate environment. With no prior expectations or context, you can quickly see what’s right in front of you — like a rain cloud or a speeding car — and then analyze it so you can make the right decisions.
We then use top-down processing to add contextual cues that give us a more accurate picture of what we are experiencing. Both types of processing are important and used side by side.