Psychology 100:12 Chapter 5 Sensation & Perception Part II

Outline Basic Sensory Processes Olfaction and gustation Touch Audition Study Question: Label diagrams of the following structures: The Ear, The Eye, The Tongue, Haptic Nerves, etc.

Ramachadrin From: A journey to the center of your mind

Sensation Signal detection theory –Human judgement and the absolute threshold > E.g., A radar operator during 9/11/01 versus a radar operator today > Sensation vs. decision > Discriminating a signal + noise from noise alone > Lax (yea-sayer) and strict (nea-sayer) criterion  E.g., Hits and false alarms on a true-false test Sensation

Signal detection theory - Payoff matrices MissHit Correct rejection False alarm Response YesNo Stimulus On Off Sensation

Signal detection theory - Gullible student (Lax; yea-sayer) 10 %90 % 40 %60 % Response TrueFalse Test Item True False Sensation

Signal detection theory - Skeptical student (strict; nay-sayer) 40 %60 % 90 %10 % Response TrueFalse Test Item True False Sensation

Signal detection theory – The Receiver Operator Characteristic Bias vs. Sensitivity Hit Rate False Alarm Rate Strict Lax Sensation

The simplified view Bitter Sour Salt Sweet Sensation Taste –Qualitative information: > Sour  H+ ions block K+ channels > Sweet  Receptors that bind glucose > Salty  amiloride-sensitive Na+ channel > Bitter (G-Protein related) > Umami  metabotropic glutamate receptor (mGluR4) Gustation Sensation Gustation

Other Taste sensations –Temperature – False temperature > Cool (mint)  Heat (capsaicin) –Astringency (tannins) – Fat  CD36 receptor Gustation

Taste buds Sensation Gustation

Taste buds –Range: ,000 > Normal  200 Fungiform foliate circumvallate = 3680 > Individual differences  Non-tasters (25%) 117 papillae per cm 2  Normal (50%) 127 papillae per cm 2  Super-tasters 165 papillae per cm 2 Sensation Gustation

Sense of smell –Olfactory Epithelium: thin layer of tissue containing the olfactory receptors – Olfactory Bulb: the brain center for smell. – Vomeronasal organs: respond to pheromones > E.g., menstrual synchronization SensationThe skin Olfaction

Skin Sensations: –Pressure –Warmth –Cold –Pain Other Candidates –Vibration, tickle and itch Haptic senses

Pain –Types of Pain fibers >A-Delta fibers: Convey the sharp immediate pain of injury. > C fibers: Convey slow, dull, burning pain that lingers after injury. Haptic senses

Pain –Gate control theory > There is a gateway for pain located in the midbrain. > The periaqueductal gray (PAG) contains neurons that inhibit cells carrying pain signals to the brain. > Role of Endorphins Ronald Melzack Haptic senses

Low High Compression Sensation Hearing –The physical stimulus >The quantitative element: Amount of compression (sound pressure). > We hear loudness, measured in decibels. Sensation Audition

> The qualitative element: Frequency of compression waves. >We hear pitch SoftLoud Quantitative Qualitative Low High Sensation Audition

Sensation The Ear Sensation Audition

Sensation Audition

Transduction in the chochlea Sensation Audition

Sensation Coding for pitch –Place theory >Frequency is determined by the place on the basilar membrane where there is maximal vibrational amplitude. >Two forms of deafness  Conduction  Nerve –Problems with place theory –Coding for time (frequency theory) Sensation Audition