Sensation & Perception

1. Sensation&Perception

2. Sensation vs Perception • Sensation – detecting physical energy from the environment and encoding it as neural signals. • Perception – the process of selecting, organizing and interpreting our senses. • Sensation is a bottom-up process; Perception is a top-down process.

3. http://honolulu.hawaii.edu/distance/sci122/Programs/p3/vase&bach.htmlhttp://honolulu.hawaii.edu/distance/sci122/Programs/p3/vase&bach.html

4. Video… “Lights, Camera, Magic!”

5. Thresholds • Absolute Threshold – when a stimulus is detectable 50% of the time; minimum stimulation to detect a particular stimulus. • Subliminal – stimuli that are below threshold; can only influence you in the short term and superficially. • Just Noticeable Difference – the minimum difference a person can tell between two things 50% of the time. • Sensory Adaptation – occurs when stimulus doesn’t change, so our sensitivity diminishes.

6. Vision P. 148

7. Vision P. 149

8. Visual Activities • Blind Spot: • Close one eye, extend index finger, and move hand around ‘til it disappears. • Hole in hand: • Roll up piece of paper, and put in front of one eye; hold your flattened hand in front of the other.

9. Visual Fields • Left and Right Visual Fields – each eye has both, they overlap, and give us 3-D Vision. • www.eyetec.net/ group3/M11S1.htm

10. Another Movie! “Perception: Inverted Vision”

11. Color Vision • Three color theory – Cones are sensitive to three wavelengths of light: red, blue, green. • Opponent process – your brain adds yellow into the picture… • Context effects – the whites of your eyes look whiter when you wear blue, but look yellow whey you wear yellow (P. 155). • Color Constancy – you see a tomato as red regardless of the context (P. 155). • Wavelength = hue; Amplitude = brightness/intensity (P. 147).

12. Hearing • Stimulus: sound waves • Damaged when sound >85 decibels. • Stereo-audition. • Amplitude = loudness; frequency = pitch • Activity – find a partner… • Locate sound.

13. Hearing P. 157

14. Touch • Four sensations: • Pressure, warmth, cold, and pain • Gate Control Theory – only one sensation at a time: pain travels on smaller fibers, other sensations on larger fibers – action in large fibers blocks action in the small. • Good Pain? Tells you when something is wrong.

15. Pain • Some people born with reduced ability to feel pain – cannot detect hunger, broken bones, fever… • Blocking Pain: • Mind over matter (meditation, Lamaze) • Acupuncture and counterstimulation • Medication (blocks pain transmission) • Endorphins (Endogenous Morphine)

16. Other Tactile • Kinesthesis – knowing where our body parts are: visually cued; knowing how to get where we want to be/do what we want. • Vestibular Sense – monitors body movements and balance: based in semicircular canals in ear.

17. Smell • Very basic; primitive sense close to brain • Pheromones?? • Smells connected to memory, and are powerful. • Smell based on chemical processes; sniffing circulates more air through nose.

18. Taste • Sweet, sour, salty, bitter • Flavor = smell + taste • >200 taste buds that each respond to chemicals in food. • Taste diminishes with age, smoking, and alcohol use. • Movie: “Tasters and Supertasters”.

19. References • http://honolulu.hawaii.edu/distance/sci122/Programs/p3/vase&bach.html • Myers, D. (2005). Exploring Psychology (6th ed.). New York: Worth Publishers. • Myers, D. (2005). Instructor’s Resource CD-ROM: To Accompany David G. Myers Exploring Psychology, 6th ed. [Computer Software]. New York: Worth Publishers. • CH05_illustration (D:\PowerPoints\Illustration PPTs) • Ch5 (D:\PowerPoints\Lecture PPTs) • www.eyetec.net/ group3/M11S1.htm • www.wesleyan.edu/wesmaps/ course0304/psyc222s.htm