As Tulving et al (1964; cited in Gleitman, 1999) found, top down processing is important under ambiguous circumstances, such as brief exposure of a stimulus, where bottom up processes are reduced in effectiveness. But we would expect that perception would be inaccurate much more of the time, if expectation plays such an important role.
Julesz (1959) illustrated that the visual system is able to reconstruct three dimensional perception from random dot stereograms , in the absence of any other depth cues. This occurs when the visual system is able to match and fuse the disparate images in each retina. In other words, stereopsis produces form and not the other way around.
In their view, visual perception of space goes beyond the image itself to include previous experience and habitual cognitive processing strategies. The main problem with the constructivist approach is that many of the top down effects described are produced in a lab, under brief exposure in conditions removed from everyday life.
Lashley et al (1951; cited in Eysenck, M. 1998) were unable to affect vision by disrupting the electrical fields in the cortex of monkeys. However, the grouping theories that they have described occur in perception even at short durations of less than 100 m/s, this suggests that they must be a bottom up process.
In top-down processing, perceptions begin with the most general and move toward the more specific. These perceptions are heavily influenced by our expectations and prior knowledge. 1 Put simply, your brain applies what it knows to fill in the blanks and anticipate what's next.
Bottom-up processing begins with the retrieval of sensory information from our external environment to build perceptions based on the current input of sensory information. Top-down processing is the interpretation of incoming information based on prior knowledge, experiences, and expectations.
A "top-down" approach is where an executive decision maker or other top person makes the decisions of how something should be done. This approach is disseminated under their authority to lower levels in the hierarchy, who are, to a greater or lesser extent, bound by them.
Top-down processing is perceiving the world around us by drawing from what we already know in order to interpret new information (Gregory, 1970). Top-down theories are hypotheses-driven, and stress the importance of higher mental processes such as expectations, beliefs, values and social influences.
Top-Down Theory of Perception. emphasize role of higher level processing; your knowledge, experience, expectations, and goals - great when information is ambiguous, incomplete, or not exactly "natural" Constructive / Intelligent Perception.
Top-down processing is information processing guided by high-level mental processes, as when we construct perceptions by filtering information through our experience and expectations.
Another introductory psychology textbook defines top-down as: “Cognitive (usually perceptual) process directed by expectations (derived from context, past, learning, or both) to form a larger percept, concept, or interpretation” (Galotti, 2014, p. 423).
1. OVERVIEW. Top down analysis is a problem solving mechanism whereby a given problem is successively broken down into smaller and smaller sub-problems or operations until a set of easily solvable (by computer) sub-problems is arrived at.
For example, suppose you receive an important letter but a few drops of water have smeared part of the text. A few letters in different words are now just smudges. Yet, you're still able to read the letter in its entirety using top-down processing.
Top-down learning refers to learning explicit knowledge first and then learning implicit knowledge on that basis (i.e., assimilating explicit knowledge into an implicit form).