Perception Friday September 4 2015 1 26 PM Is an act of memory Experience resulting from stimulation of the senses Basic concepts Involves a process similar to reasoning or problem solving Can change based on new info Occur in conjunction with actions Hard to make AI perceive like we do Facial recognition was set up in a network not code Millions of trials Direct Perception Bottom up processing Stimuli in the environment Parts are identified and put together and then recognition occurs Data driven Constructive perception theories Top down processing Using information based on expectations Knowledge driven Pain is actually top down placebo Helmholtz s Theory of Unconscious Inference Top down Some perceptions are result of unconscious assumptions we make about environment o Use knowledge to inform our perceptions Infer much about what we know Perceive in the way it s most likely based on past experiences Old view structuralism Perception involves adding up sensations The mind groups patterns according to laws of perceptual New view Gestalt organization Gestalt Law of good continuation o Laws tend to be seen as following the smoothest path Law of pragnanz simplicity or good figure o Every stimulus pattern is seen so the resulting structure is as simple as possible o Olympic circles Law of similarity o Similar things appear grouped together Provide accurate info Reflect experience Experience is important but does not overcome perceptual principles Intrinsic Oblique Effect People can perceive verticals and horizontals more easily than other orientations Light from above assumption Light comes from above sun Perceive shadows as specific information place shadows a certain way Inferring 3D even though we live in a 3D world Bayesian Inference Thomas Bayes 1701 1761 One s estimate of prob is based on two factors o Prior prob o The likelihood of a given outcome