In psychology and the cognitive sciences,<unk>  is the process of acquiring, interpreting, selecting, and organizing sensory information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was proclaimed that building perceiving machines would take about a decade, but, needless to say, that is still very far from reality. The word<unk>  comes from the Latin<unk> -, percepio, , meaning "receiving, collecting, action of taking possession, apprehension with the mind or senses." --OED.com. Methods of studying<unk>  range from essentially  biological or physiological approaches, through psychological approaches through the philosophy of mind and in empiricist epistemology, such as that of David Hume, John Locke, George Berkeley, or as in Merleau Ponty's affirmation of<unk>  as the basis of all science and knowledge.
There are two basic theories of<unk> : Passive<unk>  (PP) and Active<unk>  (PA). The passive<unk>  (conceived by René Descartes) is addressed in this article and could be surmised as the following sequence of events: surrounding - > input (senses) - > processing (brain) - > output (re-action). Although still supported by mainstream philosophers, psychologists and neurologists, this theory is nowadays losing momentum. The theory of active<unk>  has emerged from extensive research of sensory illusions with works of Professor Emeritus Richard L Gregory in a lead. This theory is increasingly gaining experimental support and could be surmised as dynamic relationship between “description” (in the brain) < - >  senses < - > surrounding.
Perception
Face perception
Body memory
Emotion
Feeling
Visual thinking
Psychodynamics
Visual perception