What is bottom up and top down processing in perception?

What is bottom up and top down processing in perception?

bottom-up processing are driven by our sensory information from the external world (e.g. our environment). Top down processing extract sensory information and they are driven by our knowledge, expectations and goals.

For example, a top down processing could be if you were on walking on the streets, and you recognize a person as either a man or a woman. Using the bottom up processing, you look for signs such as breasts, moustache, adam's apple to conclude if the person was a man or a woman.

Bottom-up processing may be called perception that begins with the stimulation of the receptors - the "small chunk" processing. It is percieving that starts with smaller, more fine details of an element building up towards a representation in our mind. The process is based on the data incoming from the environment which subsequently form a perception. It is therefore connected to all of out sensory experiences with the exception of imagining something.

Top-down processing on the other hand is processing tht begins with a person's knowledge or expectations and may be called "large chunk" processing. When percieving we form perceptions by starting with the bigger concept and work our way down to the smaller parts. An example of it may be seen when thingking of recognition of a "blob" in a picture that may actually be percieved as different objects depending on its orientation and context. Top-down processing is therefore also involved in our ability to recognise objects based on just a few features or when the majority of it is obscured.