Chapter 5 - sensation

28 views5 pages
16 Dec 2010
CHapter 5- Sensation
-how the sense system function depends on specific modalty of the info AND on the
characteristics of teh information and the state of the brain at the time it recieves it
-visual sense is rapidly changing yet appears stable
-sound however is not so variably, changes are more gradual
-sound carry around obstales, vision does not
Sensory Processing
-psych define sensation---> detection of simply properties of stimuli, such as brightness
-percetpion-->detection of objects, there location, movement and background
-the task of the sense organ is transmit signals to the brain that are coded in such a
ways was to rep faithfully the events that have occured
-def: literal meaning; leading across. This is the process where sense organs convert
energy from the enviro into neural activity
-receptor cells; release chem transmitter subs that stimulate other neurons
-dendrites respond dircelty ti tge physical stimuli without intervention of specialized
receptor cells
Sensory Coding
-Action potentials cannot be altered and are fixed in size and duration
-a code is a system of symbols or signals representing information
-two general forms of coding
-anamtomical;interpret location and the type of sensory stimulus. since
the brain does not have direct info about the phys energy on an organ, it
uses this form of coding. eg rubbing eyes. Sensory coding for the body is
-Temporal coding;coding interms of time; rate. Can communicate
quantative info to the brain. Tells you the intensity, all sensory organs use
--europe birthplace
-study of relationships between physical characteristics of stimuli and the sensation they
-two ways of measuring ppls senses
1.The principal of the Just-Noticable Difference
-ernest weber
-jnd is directly related to the magnitude of the stimulus
-diferent senses had different ratios, these ratio; Weber fractions
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
-Gustav Frechner; used tests and graph with physical and the
psych world
-the power law by SStevens; s=kib, provides a systematic way to compare
different sensory systems
-also known as difference threshold
2.Signal Detection Theory
-rely on threshold; line between percieve and not perceiving, not a fixed value, when a
particpant notices stumuls 50 percent of the time
-according to theory; every stimulus event requries discrimination between signal and
-best way to determine a persons sensitivity to the occurence of a particular stimulus
-emphazsies that sensory experience involves factors other than th actiyy of the sensory
system, such as the motivation and prior experience
-stimulus; light
-light is radiant energy similar to radio waves
-wavelength table
-other species define the visual spectrum as something else; what we cant see
sometimes they can. eg; uv rays
The Eye and its Function
-eyeball is protected
-the brain controls muscles, regulates the size of the pupil, bright and dim light
--change in shape of lense is accomodationlong
-eyes; nearsightedness; concave lense, eye too long
-farsight; convex, short eyes
-retina perfoms sensory function of the eyebecause there are no photoreceptor infront
of the optic disc, retina senses a blind spot
-b4 used to think lens was the sensory organ
-Johannes Kepler; said it was actually retina
-Schiener; lense is just the focusing device
-retina has three layers
-gangalian cells
-2 diff types of recptors
rods;sensitive to light, work in dim
cones;bright; color vision
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.