MIND: The Cognitive Side of Mind and Brain “… the mind is not the brain, but what the brain does…” (Pinker, 1997)
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MIND: The Cognitive Side of Mind and Brain the mind is not the brain, but what the brain does (Pinker, 1997)
COGNITIVE PSYCHOLOGY emerged late 1960s: The scientific study of higher mental processes, from perception and action through memory, language, thinking, and problem solving. These mental activities involve the processing of information.
COGNITIVE PSYCHOLOGYGOAL: To understand how the mind worksMETHODS: Based on scientific experimentationEXPLANATION: Focuses on the nature of mental representations and the processes that operate on them
INFORMATION PROCESSING METAPHOR: Both brain and computers process informationInformation (knowledge, representation, symbols) is independent of the physical medium
COGNITIVE SCIENCE: Interdisciplinary study of the mind emerged late 1970sCognitive PsychologyArtificial IntelligenceNeuroscienceLinguisticsPhilosophyAnthropology
NEUROSCIENCEGOAL: To understand how the brain worksMETHODS: Based on scientific experimentationEXPLANATION: Focuses on nervous system function and performance
Cognitive Psychology and Neuroscience TogetherInitially, interest, but little direct contactTwo sides of a coin; burning a candle at both endsVery difficult to map cognitive level of explanation onto brain Today, the cumulative advances in our scientific knowledge and technology have opened new possibilities for collaboration.
Cognitive Psychology provides:Logical analysis of the mental structures and processes presumed to be involved in the performance of many tasks (task analysis).This analysis used to develop cognitive tasks to assess aspects of perception, attention, and memory. Models of mental structures and processes of human perception, attention, memory, etc. based on data obtained from solid experimental procedures
Cognitive Psychology and Neuroscience:1990s: Neuroimaging studies demonstrate activation of specific brain areas when people perform classic cognitive tasks.2000s: Some neuroimaging studies help distinguish between alternative theoretical accounts of cognitive performance.
COURSE OVERVIEWVisual Perception: We are visual animalsVisual Attention: We select some, but not all, stimuli for processingVisual Awareness: We are conscious of some, but not all, experiences
PERCEPTIONRamachandran video: Phantom limb, blind sight, unilateral neglect, Capgras syndromes reveal that visual perception is not the same as sensation.
IMPOSSIBLE OBJECTSObjects to right initially look like coherent objects, but they are not physically possible.Vision does not simply register what is present. It actively constructs percepts
VISUAL PERCEPTIONACTIVE INTERPRETATION of sensory inputWe perceive the world through the filter of our knowledge and experience
Consider THIS ROOM from the perspective of:Our eyesPre-school child MooseMoose
VISUAL PERCEPTIONGOAL: To understand the 3D structure of the world around us by identifying:What objects are out there Where they are located What they are doing
Recognizing Things Single Objects: My mug in different places, orientations, lighting conditions changes location, size. Letters & Words: Type fonts, all other above variations. Faces: Different views (frontal, side), all other above variations
Three Levels of Perceptual IdentificationSuperordinate: FruitEntry level: AppleSubordinate: Granny Smith Apple
Sensory input identified at the level appropriate for the task at hand: If we want to eat an apple, we identify the object as an apple, not as a fruit or a Granny Smith apple.
Stages of Processing: A Generic Symbolic Model
Stages of ProcessingEach stage (i.e., box) is a different level of processing.Two classes of processes:Bottom-up (data-driven, sensory-driven)Top-down (conceptually driven)
A large set of detectors operating in parallel to code edges, color, movement (covered in lectures on Chapters 1 and 2).Analyzers operate in parallel.
Figure Construction MechanismOrganizes the image by segmenting (parsing) it into parts and grouping the parts appropriately.How do we know which parts go together in the figure to the right?
Figure Construction MechanismOrganizes image by binding attributes togetherGestalt Principles of GroupingMultiple glimpses, binocular disparityShape from shading, depth from texture
Figure Construction MechanismOrganizes image by determining what is figure (that which we attend to) and what is ground.
Ambiguous figures: two equally good figures constructed, as in the Necker cube.
Perceptual Representation and Comparison MechanismPerceptual Representation: The organized percept, ready for identification.The perceptual representation is compared to our stored shape knowledge (i.e., shape representations) by the Comparison Mechanism.
Top-down InfluencesLocal context and our expectations influence perception. We do not yet know how early in visual processing top-down influences of context operate.
Bottom-up processing (BU): The sequence of mental events is largely determined by the pattern of incoming information.Top-down processing (TD): The sequence of mental events is influenced by our knowledge and expectations.In perception:processing initially starts with sensation and BU processing.thereafter, BU and TD processing occur simultaneously.
VISUAL PERCEPTIONGOAL: To understand the 3D structure of the world around us by identifying what objects are out there, where they are located, and what they are doing.
Whats next?Dr. Carolyn Harley completes coverage of Chapters 1 & 2Chapter 1: Early Vision: Retina and Retinal Ganglion Cells, LGN, Primary Visual Cortex Chapter 2: From Local to Global Image Recognition: Color, Motion, Image Segmentation, Two Cortical Systems