Class Notes (811,702)
Canada (494,883)
York University (33,737)
Psychology (4,078)
PSYC 1010 (1,337)

Sensation and Perception.docx

6 Pages
Unlock Document

PSYC 1010
Agnieszka Kopinska

PSYCH 1010 Sensation & Perception Sensation  Stimulation of sense organs Perception  Selection, organization, and interpretation of sensory input Psychophysics  The study of how physical stimuli are translated into psychological experience  Fechner – the concept of the threshold ­ Absolute threshold – smallest strength of a stimulus that can be detected 50% of the time ­ Difference threshold – (JND) smallest difference that can be detected  Weber’s law – size of JND proportional to size of initial stimulus  Sensory adaptation – gradual decline in sensitivity to a constant stimuli  Signal – Detection Theory – sensory processes + decision processes  Subliminal Perception – existence vs. practical effects Major Senses  5 major senses ­ Vision, hearing, touch, taste, smell  Other less obvious senses ­ Kinesthetic and vestibular ­ Touch : heat, cold, pressure, pain Sensory Receptors  Detect environmental stimuli  Convert stimulus energy into electrochemical signals Vision  Purpose: ­ Transform light energy into a electrochemical neural response ­ Represent characteristics of objects in our environment such as size, color, shape, and location Light: The Visual Stimulus  Light can be described as both a particle and a wave  Wavelength of a light is the distance of one complete cycle of the wave  Visible light has wavelengths from about 400nm (blue-violet) to 70nm (red)  Wavelength determines hue of color The Eye  Converting light into neutral impulses  Components: 1. Cornea: where light enters the eye 2. Lens: focuses the light rays on the retina 3. Iris: colored ring of muscle, constricts or dilates via amount of light 4. Pupil: regulates amount of light The Retina  Absorbs light, processes images, and sends information to the brain  Optic disk: where the optic nerve leaves the eye/blind spot  Receptor cells: ­ Rods: black and white/low light vision ­ Cones: color and daylight vision  Information processing: ­ Receptive fields ­ Lateral antagonism Processing Visual Information  Ganglion cells – neurons that connect to the bipolar cells; their axons form the optic nerve  Bipolar cells – neurons that connect rods and cones to the ganglion cells  Optic chiasm – point in the brain where the optic nerves from each eye meet and partly crossover to opposite sides of the brain Feature Detectors  Early 1960’s: Hubel and Wiesel  Microelectrode recording o axons in primary visual cortex of animals  Discovered feature detectors: neurons that respond selectively to lines, edges, etc.  Later research: cells specific to faces in the temporal lobes of monkeys and humans Color Vision  Our visual system interprets differences in the wavelength of light as color  Rods are color blind, but with the cones we can see different colors  This difference occurs because we have only one type of rod but three types of cones  Color – determined by the wavelength of light the object reflects, not based on the inherent nature of the object ­ White: contains all wavelengths or colors, object is white if it reflects all wavelengths of colors ­ Black: object absorbs all wavelengths Trichromatic Theory of Color Vision  By mixing only three primary lights (red, green and blue), they could create the perceptual experience of all possible colors  Young and Helmholtz proposed that we have three different types of photoreceptors, each most sensitive to a different range of wavelengths Opponent Process Theory of Color Vision  Some aspects of our color perception are difficult to explain by the trichromatic theory alone  Example: afterimages ­ If we view colored stimuli for an extended period of time, we will see an afterimage n a complementary color  To account for phenomena like complementary afterimages, Herring proposed that we have two types of color opponent cells ­ Red-green opponent cells ­ Blue-yellow opponent cells ­ The third type of cells is sensitive to brightness  According to this theory – color is sensed and encoded relative to red OR green, and blue OR yellow  Our current view of color vision is that it is based on both the trichromatic and opponent process theory  Colors other than red, green, blue , or yellow invoke one of each pair to a particular degree  Sensory adaptation creates an “off-duty” time for cells, exciting the other cells Hearing: Sound Waves  Auditory perception occurs when sound waves interact with the structures of the ear  Sound waves – physical stimuli that produces sound  Without air (or a
More Less

Related notes for PSYC 1010

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.