1. On Being Human ITEC 4130 Fall 2009

2. Understanding humans Humans evolve much more slowly than technology There are limits to human capabilities - knowing what they are helps us understand what is going on

3. Three Views of Humans How to model a human! Humans are interpreters/predictors - cog. psych. & AI Humans are sensory processors - sensory psych., EE & CS systems Humans are actors in environment -activity Th., ethnog., ecol. psych.

4. Humans as I/O machines Senses vision hearing touch smell/taste proprioception kinesthesia

5. Vision Two stages in vision - physical reception of stimulus - processing and interpretation of stimulus The physical apparatus: the eye - mechanism for receiving light and transforming it into electrical energy

6. More about the eye The eye: - the light it picks up is light that reflects from objects - images are focused upside-down on retina - retina contains rods for low light vision and cones for color vision - ganglia distribution on the retina varies by species (African plains vs tree dwellers)

7. Depth and Size Perception It is a complex suite of clues *visual angle indicates how much of field of view object occupies *Is your visual field circular? *Test this using a marker on the board *visual acuity is ability to perceive fine detail *predatory birds have very high visual acuity

8. Depth and Size Perception It is a complex suite of clues *familiar objects perceived as constant size *law of size constancy *as someone walks toward you you don’t think: Man, that guy is getting taller by the second! *Cues help perception of size and depth *Accommodation (lens stretches) *Occlusion *Motion parallax *Relative size (tied to size constancy) *Aerial perspective (atmospheric)

9. Brightness *Brightness is a subjective reaction to levels of light *Measured by just noticeable difference *Visual acuity increases with luminance *Pinhole camera *Reading is improved in bright light

10. Color Perception *Color made up of hue, intensity, saturation *Cones sensitive to color wavelengths *Blue acuity is lowest *Green acuity is highest *8% males and 1% females color blind (Red/Green confusion most freq)

11. Graphical Representation at the Interface Graphical modeling and 3-D Graphical coding Graphical coding for quantitative data Color coding Color versus monochrome coding Icons

12. Compensation & Illusions http://blindspottest.com http://en.wikipedia.org/wiki/Image:Gradient-optical-illusion.svg http://en.wikipedia.org/wiki/Same_color_illusion http://en.wikipedia.org/wiki/Grid_illusion http://en.wikipedia.org/wiki/Ponzo_illusion http://en.wikipedia.org/wiki/Image:Revolving_circles.svg

13. Reading… it’s pretty complicated “Stage” model of reading (1) visual pattern perceived (2) decoded using internal language representation (3) interpreted using knowledge of syntax, semantics, pragmatics

14. Perception in reading *Reading involves saccades and fixations *Saccades are rapid movements of the eye *Without them, the retina would “saturate” and you wouldn’t see anything *Fixations are the stops in that movement *Perception occurs only during fixations *Otherwise the world would be blurred! *Word shape is important to recognition.

15. Hearing *Provides information about environment: *Distance *Direction *People can hear from 20Hz to 15kHz * less accurate distinguishing between high frequencies *Auditory system filters sounds *We can attend to sounds even in the presence of background noise *“cocktail party phenomenon”

16. Touch *Receptors in the skin: - thermoreceptors (heat and cold) - nociceptors (pain) - mechanoreceptors (pressure) *Unevenly distributed across the body *Some areas more sensitive than others *fingers are more sensitive than your back

17. 6th, 7th and 8th senses Proprioception internal awareness of your body position Kinesthesis awareness of body movement Balance vestibular organ of inner ear awareness of body orientation w.r.t. vertical

18. Movement & perception Tight integration of -perception & motor planning, -movement execution -feedback proprioceptive, kinesthetic, vestibular and visual Response time = reaction time + movement time -Movement time depends on age, fitness … -Reaction time depends on modality visual: 200ms auditory: 150 ms pain: 700ms (slow and distance related)

19. The Box Model of Memory Sensory memories vision touch auditory Short-term/ working memory Long-term Memory Sensory buffers are constantlyo verwritten Driven by attention Scratch-pad for temporary recall * rapid access (70ms) * rapid decay (200ms) * limited capacity (7 ± 2) Recency effect: recall of recent items best Evidence for several working memories Declarative memory: semantic + episodic Semantic: facts, meanings, skills, concepts, understandings… Episodic: events, time, place, emotion…

20. The Box Model of Memory Long-term Memory Episodic Semantic Semantic memory structure -provides access to information -represents relationships between information -supports inference -associative: -recall based on meaning -gives rise to meaning-related confusions -eye witness testimony…

21. Attention Focused Sustained Divided Selective Alternating

22. Attention How to focus attention at an interface? Structure the information Others…

23. Consolidation Moving information from STM to LTM? Provide: Structure Meaning Become familiar (through rehearsal)

24. Forgetting Decay Information lost gradually but slowly Interference New information replaces old (retroactive) Old may interfere with new (proactive) Inhibition You can ‘choose’ to forget Example: Parking your car… You intentionally forget all but the most recent

25. Retrieval Recall * Information reproduced from memory * Can be assisted by cues, (e.g. categories, imagery…) Recognition * Information gives knowledge that it has been seen before

26. Knowledge representation Declarative knowledge = knowing that Semantic networks Frames Scripts Procedural knowledge = knowing how Scripts Production rules

27. Semantic networks

28. Frame-based model of semantic memory Knowledge is organized in data structure Slots in structure are instantiated with particular values for a given instance of data...translation for CS people: frames  classes in the head; slots  variables/methods in the head)

29. General knowledge as frames

30. Script-based memory Scripts = using frames for stereotypical processes (e.g. eating in a restaurant) * used for interpreting situations * generalize episodic-memory events

31. Production rules Representation of procedural knowledge Condition/action rules if condition is matched, rule fires

32. Slips and Mistakes Slips are errors in execution of correct intention Capture errors Errors of attention Mistakes are errors in selection of goal or method for accomplishing it Errors of knowledge