The psychology of perception is a subfield of psychology that aims to understand and explain how humans and other animals receive information about the outside world through perception and through various cognitive processes. The issue of perception is also incredibly important in philosophy and in some other related fields, but the psychology of perception is generally based on a scientific experimental approach to the issues of interest. The process of perception begins with some physical aspect of the environment. That environmental factor interacts with sensory organs and is processed by the brain. Only after the information obtained from the environment is processed by the brain is actual conscious perception possible, and this is often subject to a variety of cognitive processes that can subtly alter the nature of what is perceived.
The first point of interest in the psychology of perception is the reception of sensory information from one's environment. One cannot hope to understand the psychological aspects of perception without knowing how the physical aspects work. Sensory information from the environment, such as light or sound, must interact with the sensory organs in order for perception to be possible at all. A central problem in the psychology of perception is that conscious perception does not give a perfectly accurate and unbiased view of the physical environment based on that sensory input. Conscious perception instead results when that sensory information undergoes a variety of neurological and psychological processes that bias and alter one's view of the external environment.
Neural processing, which also occurs prior to conscious perception, is another important focus of the psychology of perception. Sensory stimuli, upon interacting with the sense organs, are converted to electrical impulses that progress through a variety of pathways in the brain. Researchers in the psychology of perception field are interested in how these neurological processes affect the consciously perceived stimuli. They may, for instance, study individuals who have brain injuries in order to attempt to determine how physical damage to the brain affects the final outcome of conscious perception.
A variety of cognitive processes also affect conscious perception and are, accordingly, of great importance in the psychology of perception field. A variety of cognitive processes are responsible for allowing people to draw meaning from derived sensory input. They allow for facial recognition, the ability to read, and associations between known information and a given perceived environmental factor, for instance. A great deal of the research in this field is focused on these cognitive processes because they substantially alter the manner in which people perceive their environments, and because many of these processes are conscious, they are in many ways more accessible than the physical and neurological aspects of perception.