MIND: The Cognitive Side of Mind and Brain

1. MIND: The Cognitive Side of Mind and Brain • “… the mind is not the brain, but what the brain does…” (Pinker, 1997)

2. 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.

3. COGNITIVE PSYCHOLOGY • GOAL: To understand how the mind works • METHODS: Based on scientific experimentation • EXPLANATION: Focuses on the nature of mental representations and the processes that operate on them

4. INFORMATION PROCESSING METAPHOR: • Both brain and computers process information • Information (knowledge, representation, symbols) is independent of the physical medium

5. COGNITIVE SCIENCE: Interdisciplinary study of the mind emerged late 1970s • Cognitive Psychology • Artificial Intelligence • Neuroscience • Linguistics • Philosophy • Anthropology

6. NEUROSCIENCE • GOAL: To understand how the brain works • METHODS: Based on scientific experimentation • EXPLANATION: Focuses on nervous system function and performance

7. Cognitive Psychology and Neuroscience Together • Initially, interest, but little direct contact • Two sides of a coin; burning a candle at both ends • Very 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.

8. 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

9. 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.

10. COURSE OVERVIEW • Visual Perception: We are visual animals • Visual Attention: We select some, but not all, stimuli for processing • Visual Awareness: We are conscious of some, but not all, experiences

11. PERCEPTION • Ramachandran video: • Phantom limb, blind sight, unilateral neglect, Capgras syndromes reveal that visual perception is not the same as sensation.

12. IMPOSSIBLE OBJECTS • Objects 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

14. VISUAL PERCEPTION • ACTIVE INTERPRETATION of sensory input • “We perceive the world through the filter of our knowledge and experience”

15. Consider THIS ROOM from the perspective of: • Our eyes • Pre-school child Moose • Moose

17. VISUAL PERCEPTION • GOAL: 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

18. 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

19. Three Levels of Perceptual Identification • Superordinate: Fruit • Entry level: Apple • Subordinate: 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.

20. Stages of Processing: A Generic Symbolic Model

21. Stages of Processing • Each stage (i.e., box) is a different level of processing. • Two classes of processes: Bottom-up (data-driven, sensory-driven) Top-down (conceptually driven)

22. Dimensional analysis • 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.

23. Figure Construction Mechanism • Organizes 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?

24. Figure Construction Mechanism • Organizes image by binding attributes together • Gestalt Principles of Grouping • Multiple glimpses, binocular disparity • Shape from shading, depth from texture

25. Figure Construction Mechanism • Organizes 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.

26. Perceptual Representation and Comparison Mechanism • Perceptual 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.

27. Top-down Influences • Local context and our expectations influence perception. • We do not yet know how early in visual processing top-down influences of context operate.

28. Definitions • 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.

29. VISUAL PERCEPTION • GOAL: 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.

30. What’s next? • Dr. Carolyn Harley completes coverage of Chapters 1 & 2 • Chapter 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