Presentation on theme: "Neil H. Schwartz Psych 401: Senior Seminar. Neuroanatomic Level: Basic Structures Lateral Occipital Cortex (LOC) Plays an important role in human."— Presentation transcript:
Neuroanatomic Level: Basic Structures Lateral Occipital Cortex (LOC) Plays an important role in human object recognition. V1 Each V1 transmits information to two primary pathways-- the dorsal stream and the ventral stream: The dorsal stream is associated with motion, representation of object locations, and control of the eyes and arms, especially when visual information is used to guide saccades or reaching. dorsal streamsaccades  The ventral stream is associated with form recognition and object representation. It is also associated with storage of long-term memory.ventral streamlong-term memory V2 Has many properties in common with V1. Tuned to simple properties such as orientation, spatial frequency, and color, moderately complex patterns, and whether the stimulus is part of the figure or the ground.+ V4 V4 is the first area in the ventral stream to show strong attentional modulation.ventral stream Tuned for orientation, spatial frequency, and color. Unlike V1, V4 is tuned for object features of intermediate complexity, like simple geometric shapes. Visual area V4 is not tuned for complex objects such as faces, as are areas in the inferotemporal cortex.inferotemporal cortex Inferotemporal cortex (IT) Crucial for visual object recognition and is considered to be the final stage in the ventral cortical visual system.visual object recognition Selective for the shape or color of a stimulus and respond more to complex than simple shapes. A small percentage of IT units are selective for facial images. Can be modulated by attention. Can show both short or long term memory for visual stimuli and their selectivity can be modified by experience.memory
Anatomical Level: Fusiform Gyrus FUSIFORM GYRUS The magic of the FUSIFORM GYRUS1. Responsible for interpreting complex patterns, like faces places, color, words, etc. 2. It is also trainable. For example, bird watchers get better at recognizing species with practice.That is, the FG turns on after practice; but without the practice, it does not. 3.It is smaller in people with Autism. 4.It moderates amygdala activation– at least with potentially threatening faces causing avoidance behavior following a fear response but only when it is activated.
Theoretical Level: Explanatory Models: Geon Theory Geon Theory: Geon theory assumes that objects are represented as an arrangement of simple, viewpoint-invariant, volumetric primitives, termed geons, such as bricks, cylinders, wedges, cones, etc. A “geons” is a “geometric ion.” The term “ion” translates to “component or element,” The idea is that we recognize faces (and other objects in our environment) by breaking them into geometric elements. Biederman identified about 30 basic shapes and said that whenever we see something, our mind quickly “understands” it as an ordered collection of those basic shapes.
Theoretical Level: Explanatory Models: Visual Gist Perception Rapid characterization of a scene. People can identify a scene within 100 milliseconds. This discounts Geon Theory. Recognizing patterns of patterns based on the typical spatial feature components common to scenes. E.g. cityscapes, playground at a park, beaches, etc.
Theoretical Level: Explanatory Models: Visual Gist Perception Scene gist has a powerful influence on how we see an object embedded in a scene. The IT cortex has many sub-regions specialized for object identification– pattern processing clusters. The more clusters we need, the more neurons recruited; the more they become tuned for specific patterns. (chefs, dance critics, fly fisherman, etc.)
Theoretical Level: Explanatory Models: Visual Gist Perception How is it researched? http://images.google.com/imgres?imgurl=http://psyc.queensu.ca /qvcl/proj- ContextualBias.jpg&imgrefurl=http://psyc.queensu.ca/qvcl/projs. html&usg=__VcsbsOxcaso40soNIh_dEcVngTM=&h=307&w=400 &sz=73&hl=en&start=3&sig2=2BKsLTNCGewWIP8W1HMl0Q&u m=1&itbs=1&tbnid=WhONvD_xz4Im3M:&tbnh=95&tbnw=124&p rev=/images%3Fq%3Dvisual%2Bgist%2Bperception%26um%3D1 %26hl%3Den%26sa%3DN%26rlz%3D1G1GGLQ_ENUS240%26tb s%3Disch:1&ei=WIbES7WEEYvWmgOb1fS_Dg
Cognitive Explanation: The Role of Working Memory: Visual and Verbal “An entity in visual working memory can be thought of as a temporary grouping or nexus, where links are formed between active visual patterns derived from the visual image on the retina scene information and information relating to non-visual stored meanings– either verbal, motor, tactile, etc.”
Cognitive Explanation: The Role of Working Memory: Verbal WM Temporary transitory store Can hold speech information for 2 seconds. Called an echoic loop.
Cognitive Explanation: The Role of Working Memory: Attentional Processes Create temporary bindings of visual and verbal material in working memory. Bindings come about as a result of control processes. “Cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task.”
Cognitive Explanation: The Role of Long-term Memory LTM is not a distinct unit; it is distributed all over the brain. Every neuron both processes and stores information. V4 processes and stores visual pattern information; as we learn to identify new patterns, neural circuits are formed and strengthened to process those patterns. The IT cortex processes and stores higher-level cognitive sequencing operations that relate to the sequence of steps to be carried out when performing a visual task (e.g. reading a map).
Cognitive Explanation: The Role of Long-term Memory: Two Types Explicit Memory What can be explicitly recalled. Only a little of what is seen makes it in as explicit. To be explicitly learned, attentional focus is absolutely necessary. To be enduring: (a) a 24-hour consolidation period is essential, and (b) there must be an internal or external consequence attached with a cognitive act. (successful outcome, useful conclusion or reward). Implicit Memory Whatever is retained every time something is seen. It is left as a trace. Very little of this can be explicitly recalled. More of what is seen is stored in implicit memory.
The Entire Process: Beginning to End Wonderfully described: Pages 118 – 120.
Implications for Design Make objects easy to identify Use the most typical exemplars of an object class. Use the angle that is most typical. Use views that show critical relationships between structural parts. (ambulance) Make objects novel Novelty holds attention (e.g. gist-object conflict; visual puzzles)
Implications for Design Make use of well-known symbols Cases an automatic and rapid activation of the symbol’s associated meaning. The symbol meaning connection is known as branding. Be wary of the tension between novelty and branding. Images should evoke emotion – positive valence; and high arousal. Behavior, however, does not always follow emotion.