2. In order to design something for someone, we need to understand the capabilities and limitations of that person How humans perceive the world around them How humans store and process information and solve problems How humans physically manipulate objects

3. Model Human Processor Our Model Cognitive System Perceptual System Motor System CPU I/O Memory

4. Input via the senses Sight Hearing Touch Taste Smell Output via motor control Limbs (feet?) Fingers Eyes Head Voice

5. Cornea and lens focus light onto the… Retina, which contains Photoreceptors: rods - brightness cones - color (red, green and blue) Ganglions, which are nerve cells that... (X-cells) - detect pattern (Y-cells) - detect movement Fovea - center of vision

8. Depth Size constancy - smaller means farther Occlusion - obstructed means farther Texture - finer means farther Brightness - contrast (and flicker) Color 150 hues 7 million shades

9. Saccades - eye scans forward Fixations - eye is still Perception happens 94% of the time Regressions - eye looks back (complex) 9pt,12pt equally legible Books faster than computers

10. Auditory canal -> eardrum -> ossicles -> cochlea -> cilia Sound parameters Pitch - frequency Loudness - amplitude Timbre - waveform of sound Stereo location of source Cocktail party effect

11. Haptic perception Skin receptors thermoreceptors - heat, cold nociceptors - intense pressure, heat, pain mechanoreceptors - pressure Two point test - haptic accuity

12. Kinesthesis - Do you know where your limbs are? Reaction time vs. accuracy Fitts’ law: Movement time = a + b log (distance/size + 1)

13. Three kinds of memory sensory short term long term Sensory memory Attention Working memory Rehearsal Long-term memory

14. Human Cache Memory Iconic memory - visual Persistence of vision.5 seconds Echoic memory - aural Haptic memory - touch Arousal - level of interest or need

15. BIRU MERAH KUNING HIJAU

16. BIRU KUNING HIJAU MERAH BIRU KUNING HIJAU MERAH BIRU KUNING HIJAU MERAH

17. Human DRAM (Dynamic random-access memory) 70ms access time 200ms refresh time Size: 7 +/- 2 items digits chunks words Recency effect - last is best

18. 25439762608 456 295 1413 HEC ATR ANU PTH ETR EET

19. The Human World-Wide Web Two types episodic - events, organized temporally semantic - facts, organized associatively Representations semantic nets frames scripts

21. Extends semantic nets to include structured hierarchical information University Fixed: type of school Default: has colleges Variable: public/private Universitas Gunadarma Fixed: type of University Default: public Variable: campus

22. Stereotypical information Entry conditions: need job, have money Result: educated, less money Props: books, schedule, new car Roles: instructor talks, students listen Scenes: classroom, dorm Tracks: internships, apprenticeships

23. How does information get from short term memory into long term memory? Total time hypothesis - hit the books Distribution of practice effect - don’t cram Meaning - concrete better than abstract faith age cold tenet quiet logic idea value past boat tree cat child rug plate gun flame head Structure, familiarity and concreteness

24. Decay Logarithmically - forget most early Jost’s Law - if two equally strong memories at a given time, then the older is more durable. Interference retroactive interference - old phone number (later learning) proactive inhibition - driving to the old house (previous memories) emotion - good old days, forget the mundane

25. How do we recall details? Categorization Visualization 1 roti 2 sepatu 3 pohon 4 pintu 5 sarang 6 tongkat 7 surga 8 pagar 9 teh 10 ayam

26. How is information processed and manipulated? Animals - receive and store info, but do not process it as well as humans Computers - receive and store info better then humans, but do not process it as well as humans

27. Humans use information to Reason & solve problems Even if the info is partially missing or completely absent! Human thought is conscious & self-aware capable of imagination

28. Inferring missing information Deductive - conclusions Inductive - generalizations Abductive - suppositions

29. If A then B A. Therefore B not B, therefore not A. Telepon berdering pada saat saya mandi Bila saya mandi, maka telepon berdering Bila telepon berdering, saya mandi Bila saya tidak mandi?

30. Specific A has property B then all A is B Gajah memiliki belalai Komputer lambat Lelaki memiliki kumis Perempuan memakai anting

31. From fact to the action that caused it Mata bengkak Tanah Becek Helai rambut panjang di kemeja

32. Using knowledge to find a solution Gestalt theory Problem space theory Analogy

33. Finding new solutions Reproductive problem solving Learned behavior, trial and error Behavioralist Fixation Productive problem solving Invention, innovation, insight

34. Mapping out a solution step by step Problem states, goal state, current state Legal state transition operators Heuristics, e.g. means-ends analysis Examples Games: 15 puzzle, chess Tasks: Setting the VCR clock Life (emphasis on “legal”)

35. Applying one solution to a different problem Analogical mapping Purely productive reasoning is hard (10%) Drawing analogies is easier (80%) Existing solution “semantically close” to problem domain

36. Solving problems that are not completely new e.g. Chess Same goal (different goal states) Same transitions Different “skills” Problem groups novices group problems superficially experts group problems conceptually

37. How is skill acquired? General rules Specific rules Tuned rules Proceduralization Generalization

38. How do we make mistakes? Slips - change in context of skill Mental models - incorrect interpretation of the evidence

39. How do we use what we know about humans to make better user interfaces? Guidelines Models Evaluation