Modularity of mind: we have these information encapsulated modules that process certain low level stimuli. Top down, higher order processes cannot influence the stimuli. Controversial opinion. Impairment in Dorsal (where) pathway: 1. Akinetopsia: visual motion blindness. can see the object but not movement. broken up motion. 2. Optic ataxia: · cannot estimate movement and direction of object in space. · you can name objects, cannot grasp them. . they can have problems on eye movements and grasping, but it depends on the area of the brain with brain damage. · functional specificity in visual association pathway. impairment in ventral (what) pathway: 1. Object visual agnosia problems in object recognition. recognition can be selective in categories, proving functional specificity. they can see objects fine, but not recognize them. might be able to recognize with other senses. Part in the brain functionally specific: Extra-striate body area (EBA): the brain area involved in processing non-facial body parts. Para-hippocampal place area (PPA): the brain area responsible for the conscious recognition of places and scenes. Fusiform face area (FFA): the brain area responsible for the conscious recognition of faces Prosopagnosia: cannot recognize faces, relies on non facial characteristics to recognize. problem with attaching meaning to faces. people perceive the face holistically/ top down.
- results from brain injury to FFA - genetic component. Apperceptive Visual Agnosia: · Ability to control actions (reaching, grasping) is still intact . they can detect feature of objects · A failure in recognizing objects because problems with perceiving the elements of the objects · Single visual feature perception (e.g., colour, motion) are relatively intact, but there are problems grouping visual features into meaningful percepts. . they cannot copy the images that well however they can draw from memory. Associative visual agnosia . An inability to associate visual input with meaning . They can copy, but not do well with memory. . Leads to problems on tests that require: · Drawing objects from memory · Naming objects · Indicating the functions objects · Determining if a visual object is a possible or impossible object Object Recognition Theories . Bottom-up processing: the influence of information from the external environment on perception o Information from the primary visual cortex propagates down the "what"and "where" pathways to be processed. · Top-down processing: the influence of 'internal' knowledge (expectations, context and goals) on perception. o Information from final stages of visual pathway processing is sent back to the visual cortex via feedback connections to exert influence. · pattern recognition theories emphasize: o identifying a pattern in visual input
o matching the pattern in visual input to existing pattern stored in memory. o a probe is generated when you view something. The highest similarity between the probe and memory trace determine recognition. . Template matching theory: each object has a template in LTM. (simplistic) o There is very variability in the stimuli. . Prototype theory: o avg representation of object concept. recognition is determined by a 'good enough' match flexible object identification o evolve over time.