1. Perception and the Senses

2. QOTD

3. Samantha Jacob, Eliza Granahan-field, Grant Vanek, Quinlyn Ambrose, Brady Goldsworthy If you had to choose a sense to lose, which would it be? a) vision b) audition (hearing) c) olfaction (smell) d) gustation (taste) e) touch

4. Hayley Park Do you think that our individual perceptions are influenced by other aspects of our lives such as beliefs, memories, backgrounds, etc.? A) yes B) no C) depends

5. Ryan Wolsky The textbook mentions football players not feeling injuries until after a game due to anti-nociceptive signals. Have you ever had an experience such as this where you didn't realize the extent of your injury until well after it occurred? A) yes B) No C) Can’t remember due to TBI

6. Mary Sarkisian If you think about a taste will you trigger your senses and start to taste it? a) yes b) no (next, replace taste -> smell)

7. Big Questions How many megapixels are our eyes? How awesome are our other senses?  Sensation: the physical sensors Is perception veridical, or just a convenient illusion? Is it a hard problem? How does it work?  Perception: internal encoding of sensory inputs into meaningful patterns  Illusions: reveal the tricks our brain uses..

8. Basic senses SenseStimulusReceptors

9. Psychophysics Absolute threshold  Lowest level of stimulus intensity for 50% response Just-noticeable difference (JND)  Difference in stimulus intensity for 50% response

10. We’ve got a pretty kick- ass set of senses!

11. How Many Megapixels?? Retina has ~100 mega-rods, only ~5-7 mega-cones Fovea can resolve about 30 cycles-per-degree (requires cone spacing of ~.3 arcmin) = ~300 dpi at 10” (close!) Focal length of human eye is ~22mm, max ISO about 800

12. Perception: Open Them Doors!

13. Dali!

14. How Does it Work? 1. Contrast, contrast, contrast  Light/dark, color, time (adaptation) – just tell me the news! 2. Ass + u + me = visionary!  The brain has to make many assumptions based on “normal” visual inputs  Easy to trick it with improbable coincidences..

15. Contrast Illusions A = B?? No Way!

16. Contrast Illusions A = B?? No Way! Way!

17. Color Contrast

19. Time Contrast (we have a model of this)

20. Time Contrast

21. Ok Go!

22. Optic Pathway

23. Retinal Contrast Filtering

24. V1

25. Visual Hierarchy: What vs Where 25

26. 26

27. Hierarchy of Detectors.. 27 Each stage builds set of assumptions based on typical environmental input Shape from shading Depth cues: occlusion, texture, etc

28. Shape from Shading

29. Depth Cues

31. 3D!

32. Is Perception Veridical? Perception is subjective So what does “veridical” mean? Cultural, language effects? Expectation effects?

33. Enter the Matrix..

34. The Chair Category