1. Olfactory bulb receives input from olfactory receptors which contact mucus in nasal cavity Smell

2. There are thousands of different receptors for different kinds of molecules Smell

3. Pheromones are not smells Pheromones are chemical signals sent from one animal to another Pheromones

4. Pheromones either induce a behavior in another animal or cause some physiological change Very common in insects...not so common in mammals...unclear role in humans Pheromones

5. For example: Androstenone, found in male pig saliva, causes a female pig to allow the male to mate with her Fun Facts about Pheromones

6. androstenone is also found in the sweat of human males! Does androstenone (or pheromones in general) affect humans? Design an (ethical) experiment… Fun Facts about Pheromones

7. Kirk-Smith & Booth (1980) sprayed some of the seats in a dentist’s waiting room with androstenone Compared to a control condition, more women used the androstenone seat Fun Facts about Pheromones

8. Fewer men used the androstenone seat ! Fun Facts about Pheromones

9. Other possible ways in which pheromones influence humans: – synchronization of menstrual cycles – mate selection - attraction to opposite major histocompatibility complex Pheromones

10. Pheromones do not control behavior! Human behavior is largely under top-down influences, but may be affected subtly by pheromones It is unclear whether molecules such as androstenone even qualify as pheromones - they may be just like other odour molecules Pheromones

11. “It is now possible to manufacture synthetic human pheromones and such compounds are often used in research as they are relatively easy to make, convenient to store, and easy to apply.” Pheromones

12. Upcoming: Read article by Gregory for February 16 th Read chapter by Pinker for February ~28 th

13. Vision

14. Seeing Seeing is the process of converting electromagnetic radiation into a conscious mental event

15. Seeing visual system faces many challenges –too much information –too little information –conflicting information –ambiguous information

16. Seeing too much information

17. Seeing too little information

18. Seeing Conflicting Information

19. Seeing Ambiguous information

20. Seeing We will consider two aspects of vision to explore how the brain overcomes these challenges: –Seeing depth –Seeing in color

21. Seeing Remember that the only information the brain gets is a 2D pattern of light on each retina

22. Seeing Remember that the only information the brain gets is a 2D pattern of light on each retina Our rich vivid visual experience is built out of those sparse inputs!

23. Seeing Remember that the only information the brain gets is a 2D pattern of light on each retina Our rich vivid visual experience is built out of those sparse inputs! Put another way, everything your brain needs to “see” is encoded in those patterns of light energy

24. Seeing Remember that the only information the brain gets is a 2D pattern of light on each retina Our rich vivid visual experience is built out of those sparse inputs! Put another way, everything your brain needs to “see” is encoded in those patterns of light energy …well almost everything

25. Light is an oscillation (a wave) in the electromagnetic field Light

26. What are some characteristics of light waves? Properties of light

27. What are some characteristics of light waves? – amplitude/intensity - how big of a fluctuation in the field/how many waves – frequency - how many fluctuations (waves) pass by a certain point in a given period of time – polarization - the orientation of the waves Properties of light

28. What perceptions are associated with those physical properties? Properties of light

29. What perceptions are associated with those physical properties? – Intensity is associated (loosely) with brightness – Frequency is associated (very loosely) with color – Polarization isn’t sensed by humans (but it is by some insects and birds!) Properties of light

30. Light The spectrum is the range of frequencies of electromagnetic waves

31. The eye – curved cornea – lens – retina – fovea – optic disk Using Light

32. Light is focused on the retina by the curvature of the cornea and the lens – Flat lens (relaxed muscles) focuses distant points Using Light

33. Light is focused on the retina by the curvature of the cornea and the lens – Accomodation: Bulged lens (muscles flexed) focuses on near points Using Light

34. Light is focused on the retina by the curvature of the cornea and the lens Constriction of the pupil limits how much light gets in AND reduces the amount of focusing required of the lens Using Light

35. photoreceptors transduce incoming light ganglion cells send signals along to the brain The Retina has layers of cells