3 Processes of Pattern Recognition. Sensation – you have to detect or see the pattern Perception – you have to organize the features into a whole Memory – you have recognize you have seen this pattern before and remember its label. Agnosia.
(a) Left and right hemispheres of the brain, showing apperceptive agnosia usually is limited to posterior regions of the right hemisphere parietal lobe. (b) Both left and right hemispheres have cross-hatched regions at the junction of the temporal and occipital lobes, the region usually damaged in associative agnosia.
1. Detecting the features in a visual stimulus is a separate (and later) process from the sensory steps that encode a stimulus into the cognitive system. (sensation)
2. Detecting the visual features is critical in constructing a perceived pattern, a percept. (perception)
3. There is a separate step involved in hooking up the pattern with its meaning and name, involving the visual association from the pattern to the knowledge stored about it in memory. (memory)
Binocular pathways of information flow from the eyes into the visual cortex of the brain. The patterns of stimulus-to-brain pathways demonstrate the contralaterality of the visual system.
The classic cognitive research on the characteristics and processes of visual sensory memory was reported by Sperling and his coworkers.
Sperling used a special apparatus for presenting visual stimuli, the tachistocope, commonly known as the T-scope.
The “Ecological Validity” Challenge
Based on the work of Haber, ecological validity refers to the fact that methodologies and tasks should resemble the real-work ecology of cognitive processing.
A portion of the PDP network for recognizing four-letter words. The bulk of the illustration involves identifying the first letter of the word.
A possible display that might be presented to the connectionist model of word recognition and the resulting activations of selected letter and word units.