Textbook Notes (363,094)
Canada (158,187)
Psychology (756)
PSYC 101 (70)
Peter Graf (13)

Sensations, Attention

4 Pages
Unlock Document

University of British Columbia
PSYC 101
Peter Graf

Chapter 5 • sensation: process of detecting phys. Energy (stimulus) from environment and conversion into neural signals Interactive Processing • Bottom-up Processing: analysis of the stimulus that begins with sense receptors, working up to level of brain and mind • top-down processing: info processing guided by higher-level mental processes as we make perceptions, drawing on experience, expectations • interactive processing: combo of the two types of processing mentioned above Psychophysics • how phys. Stimuli (sensations) are translated into psychological experiences (perception) • quantitative description of the relationship btwn intensity of sensations and perceptions Thresholds • absolute threshold: dividing line between what signal has detectable energy and which doesn't • difference threshold: min amount of stimulus intensity change req'd to produce perceptible change (JND: just noticeable change) • min. diff. between two stimuli req'd for detection 50% of the time Signal Detection Theory • useful for computing how/when presence of faint stimulus/signal amid bg noise(or other stimulation) is detected • assumes that there is no single abs threshold; detection depends on: experience, expectations, motivation, fatigue level Difference Threshold • Method: present base stimulus and comparison stimulus; use diff. base stimuli on diff. trials; comparison stimulus differs from base by some amt. • Task: decide whether the two stimuli are same/diff on each trial Weber's Law • to perceive a diff. between 2 stimuli that differ by a constant percentage • increase in stimulus needed to produce JND defined as dR = C * R (dR-diff in stimulus needed, C-Constant eg. .10, R-intensity of original (starting stimulus) • eg. to hear increase in tone at 50 decibels, comparison stimulus needs 55 Subliminal Threshold • stimuli below abs threshold for conscious awareness SensoryAdaptation • diminished sensitivity to stimulus as consequence of constant stimulation by that stimulus • nerve cells fire less often • permits us to perceive what is useful Wavelength • hue=dimension of color determined by wavelength Intensity • amt of energy in wave determined by amplitude; related to perceived brightness The Eye • fovea (pt of central focus) • optic nerve does to brain's visual cortex • retina – converts images seen by lens into neural signals for brain Accomodation • process by which the eye's lens changes shape to focus on near/far objects on retina Feature Detection • nerve cells in visual cortex respond to features eg. edges, angles, movement Visual Info Processing • optic nerves connect to thalamus, which connects to visual cortex Theories of Color Vision • Trichromatic Theory: retina contains three receptors that are sensitive to RGB • Opponent Process Theory: Hering-four primary colours combined in pairs of red-green, blue- yellow, black-white Colours • Subtraction of Colours: 3 primary colours are mixed, subtraction of wavelengths occurs and black is result • Addition of Colours: 3 primary colours mixed, wavelengths added, white is result • Colour Blindness: genetic disorder, people blind to some colours • Protanopia: red cones filled with green photopigment • Deuteranopia: green cones filled with red photopigment • Tritanopia: lack of blue cones Audition • sound waves composed of compression, rarefaction of air molec Sound Properties • Frequency (pitch): dimension of frequency determined by wavelength of sound • intensity (loudness): amt of energy in wave, determined by amp. relates to perceived loudness • timbre: simplicity/complexity of wave Ear • cochlea: part with liquid that rubs fibres or something that sends signals Theories of Audition • Place Theory: sound freqs stimulate basilar membrane at specific places resulting in perceived pitch • Frequency Theory: rate of impulses traveling up auditory nerve matches freq of a tone, enabling us to sense pitch • localization: sounds reach one ear faster than the other to localize it Hearing Loss • Conduction Hearing Loss: caused by damage to mechanical system that conducts sound waves to cochlea • Sensorineural HL: caused by damage to cochlea's receptor cells or to auditory nerve (nerve deafness) • older people hear low freqs well, suffer HL when listening for high freqs • cochlear iplants Pain • Biopsychosocial Influences
More Less

Related notes for PSYC 101

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.