Mechanisms for Top - down Perceptual Processing

If we are to understand how human perception occurs, then we must first identify the mechanisms that drive perception. It is commonly believed that perception is influenced by both bottom-up processes (raw sensory input), and top-down processes (expectationdriven matching). What is not fully understood is how the human mind uses expectations and assumptions to manipulate what we call conscious experience. Researchers have presented several mechanistic explanations. The four most convincing theories are explored and analyzed in this paper. These contrasting theories explain top-down perception as either 1) genetically-coded and innate, 2) learned mechanisms, 3) tightlycoupled feedback loops, and 4) statistically-driven models. I conclude by showing that these theories are not in direct conflict, and that the human mind most likely uses a combination of techniques to make sense of the world. By drawing on such differing explanations of perception, I explain how a combination of these mechanisms might frame a theory of human perceptual cognition.