Sensation & Perception

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.

Video… “Lights, Camera, Magic!”

Thresholds Absolute Threshold – when a stimulus is detectable 50% of the time; minimum stimulation to detect a particular stimulus. 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. 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. 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. Sensory Adaptation – occurs when stimulus doesn’t change, so our sensitivity diminishes.

Vision P. 148

Vision P. 149

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

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

Another Movie! “Perception: Inverted Vision”

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

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

Hearing P. 157

Touch Four sensations: Four sensations: Pressure, warmth, cold, and pain 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. 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. Good Pain? Tells you when something is wrong.

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

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

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.

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”.

References /vase&bach.html /vase&bach.html /vase&bach.html /vase&bach.html Myers, D. (2005). Exploring Psychology (6 th ed.). New York: Worth Publishers. Myers, D. (2005). Exploring Psychology (6 th ed.). New York: Worth Publishers. Myers, D. (2005). Instructor’s Resource CD-ROM: To Accompany David G. Myers Exploring Psychology, 6 th ed. [Computer Software]. New York: Worth Publishers. Myers, D. (2005). Instructor’s Resource CD-ROM: To Accompany David G. Myers Exploring Psychology, 6 th ed. [Computer Software]. New York: Worth Publishers. CH05_illustration (D:\PowerPoints\Illustration PPTs) CH05_illustration (D:\PowerPoints\Illustration PPTs) Ch5 (D:\PowerPoints\Lecture PPTs) Ch5 (D:\PowerPoints\Lecture PPTs) group3/M11S1.htm group3/M11S1.htm group3/M11S1.htm group3/M11S1.htm course0304/psyc222s.htm course0304/psyc222s.htm course0304/psyc222s.htm course0304/psyc222s.htm