1. Two classes of thermoreceptors: warm and cold Thermoception

2. Taste (Gustation) Taste buds contain chemical receptors

3. Taste What are the various “tastes”?

4. Multi-dimensional scaling reveals several “varieties” of tastes: –sweet –salt –bitter –sour –umami (MSG) - protein receptor? –fat receptor? Taste

5. What you “taste” depends critically on what you’ve recently been tasting –taste receptors adapt and reduce firing over time –for example: eating something salty reduces the perceived saltiness of subsequent foods Taste is Relative

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

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

8. Olfactory receptors use a “lock-and-key” mechanism - only specific molecules will bind with a given receptor Smell Receptor Odor Molecules

9. Odor recognition is excellent in humans but odor identification (naming) is very poor Women tend to be (slightly) better than men at naming smells Smell

10. Smell is strongly influenced by “top-down” processes such as what you are expecting to smell Smell

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

12. 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

13. For example: Alpha Androstenol, found in male pig saliva, causes a female pig to allow the male to mate with her Fun Facts about Pheremones

14. Alpha androstenol is also found in the sweat of human males! Does alpha androstenol (or pheromones in general) affect humans? Design an (ethical) experiment… Fun Facts about Pheremones

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

16. Fewer men used the alpha androstenol seat ! Fun Facts about Pheremones

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

18. Pheromones do not control behavior! Human behavior is largely under top-down influences, but may be affected subtly by pheromones Pheromones

19. What kind of energy does the visual system sense and perceive? The Visual System

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

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

22. 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

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

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