Sensation and Perception Chapter 4

Sensation & Perception The Basics

What Are They? Sensation Perception Stimulation of sensory receptors and sending of sensory info to brain Automatic Psychological process in how we interpret sensory stimulation Reflects learning, expectations & attitudes

Absolute Threshold Weakest amount of stimulus that can be sensed Differs from person to person

Sense Stimulus Receptors Threshold Vision Electromagnetic energy Rods and Cones in the skin A candle flame viewed from a distance of about 30 miles on a dark night Hearing Sound waves Hair cells of the inner ear The ticking of a watch about 20 feet away in a quiet room Smell Chemical substances in the air Receptor cells in the nose About one drop of perfume diffused throughout a small house Taste Chemical substances in saliva Taste buds on the tongue About 1 tsp. of sugar dissolved in 2 gallons of water Touch Pressure on the skin Nerve endings on the skin The wing of a fly falling on a cheek from a distance of about .4 inch

Difference Threshold The minimum amount of difference detected between two stimuli Varies from person to person

Signal-Detection Theory Distinguishing sensory stimuli that takes into account strengths, as well as setting, mood, attitude, motivations, etc…. High school vs. college

Sensory Adaptation Process of becoming more sensitive to weak stimuli and less sensitive to unchanging stimuli City noise, waves at beach

Vision Featuring Your EYEBALLS

Let there be….LIGHT Electromagnetic energy Comes in wavelengths Main colors of spectrum- from longest to shortest wavelengths ROY G. BIV

AHH…..MY EYE!! http://www.biologymad.com/resources/eye.swf

The Blind Spot Place in your eye that doesn’t have photoreceptors

Rods Vs. Cones Rods are sensitive to brightness of light Cones provide color vision

Dark and Light Adaptation Adaption to bright light happens more quickly that adaptation to dark

Visual Acuity The ability to see visual details in normal light Nearsighted farsighted

Color Vision

Cones and Color Vision Blue, green & red cones, when all stimulated…color! Images are made of many tiny dots of color, called pixels

After Images

Color Blindness Absence or malfunction of the cones Red-green color blind is common Totally color blind less common

Hearing Featuring YOUR EARS

How does it work ? SOUND WAVES

Pitch How high or low a sound is

Loudness Sound measured by dB Zero dB is threshold of hearing

Locating Sounds Yes.

Deafness Conductive Deafness Sensorineural Occurs from damage to middle ear Sensorineural Damage to inner ear