PSY270H1 Study Guide - Detection Theory, Stim, Absolute Threshold

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Published on 19 Aug 2012
School
UTSG
Department
Psychology
Course
PSY270H1
Page:
of 11
PSY270 JULY 5, 2012
LECTURE 2: PSYCHOPHYSICS AND PSYCHOBIOLOGY
GORIALL STUDY
- SAT
THE DOOR STUDY
- CHANGE BLINDNESS
- 45% DIDN’T NOTICE
PSYP RELAtionship between stim and perception how we actually see things perception input
stimulus, example which one sweeter
Phys stimuli and phsy process and perception anatomy and phy phys components of perceptions,
structure and function of the nervous system, brain regions smaller is neurons, example electrical
signals eeg and single cell recordings, look at face and which brain region lights up, phys components
Gustav
- Founders of pp
- Founder bc how perception study of the mind be investigated by evifence based approach
- Linked perception with body
- Mind was philo
- He brought mathematical formulas and evidence
- Perception to measurable components
Detection
- What is measure of detection of stim detection
- Smallest detect
- Abs thr 50 perc proabbilty detect it, 50 see or hear vs 50 don’t see or hear
- Light smallest amount of light can see
- Smallest amount of pressure feel
- Or smallest amount of sound pressure can sense
- Theoritcxal threshold vs empircale
- Hyo is all or nothing, until reach respond no and then yes staircase function
- Perception not all or nothing more of a curved function as more intense the proabbilty increases
- Reality 4.5 50 say yes and other say no
- Towards the end high or low greater not and detetcting
- 50 percent
Cont
- 4 methods
- Constant stim
- Limits
- Adjustmebt
- Staircase
- What is threshold needed to detect a sensation or stim
Const
- Bc giving part a standard set and keep on showing random intervals
- Bottom light intessity
- Give them predefined light intensity and present 10 times and randomly and have respoind yes
or no and compute average
- Mult trials where intensity is detected 50 percent of time
- Average of 180 abs threshold
Limits
- Ascending or desc order
- As start of low and go higher until no to yes to detecting stimk
- Des loud and decrease until switch to yes to no
- Crossover point yes or no or yes to no
- Multiple trials and identify cross over point which is cvariable
- Why within ind not always the same always noise internal or external
- Internal gurgling of stomach, neurons always firing
- External dropping pen
- Much more efficient or superior the constrant stimuli, narrow stimuli much better
- Tally up and average
Adjustment
- Extension limits
- Present stim and adjust intensity observer or experimental does
- Adjust until barley notices it
- Repeat trials lowers or higher pplay around
Staircase
- Limits
- Better detecting absolute threshold and exact boundsaries
- Exact as limits, asc or desc,
- Example descending, lower and lower till no and then increase a little about
Common sense abs threshold
- Vision candle flames 30 miles away
- Hearing ticking watch 20 feet away
- Vestibular tilt less then a minute on clock
- Taste teaspoon of sugar in gallon of water
- Smeel perform drop a perfume 3 rooms
- Touch wing fall 3 inches
Discrimation
- Between stimuli
- Differences threshold two stimuli
- Smallest dif between two stimuli
- Jnd smallest differnve
- Icing half in and half out two weights judge weight in hand may be little different but not detect
- Not stimuli multiple difference but one like weight or volume
Contd
- Same methods for abs thres
- Increasing constant etc
- Usuall give standared
- 100 grams standard and another to compare like 102 and what is heavier or any other
dimenionsion and weight it and change comparision stimulus
Contd
- Cant use 50 bc then saying cant tell dofference
- 50 is subjexirve equality not different, 100 grams and 100.5 no difference
- Grap 10 0percent where see eavier and 100 lighter half from 25 to 0 is interval of uncerstainity,
75%
- 75 and 25, 102 minus 98 aqnd divide 2 and is value can detect
- 101 aftrer 100, not and 102 can and this is discrimation threshold
contd
- Weight increases so does differcne threshold
- So 110 so need more to discrimate between 110 then 100
- Proption however stays the same
- Candle 10 candles add 1 see
- In room 100 candles and and 10
- Dl increases proportion satsys same
- Dl/100 and get constant

Document Summary

Psyp relationship between stim and perception how we actually see things perception input stimulus, example which one sweeter. Founder bc how perception study of the mind be investigated by evifence based approach. What is measure of detection of stim detection. Abs thr 50 perc proabbilty detect it, 50 see or hear vs 50 don"t see or hear. Or smallest amount of sound pressure can sense. Hyo is all or nothing, until reach respond no and then yes staircase function. Reality 4. 5 50 say yes and other say no. Towards the end high or low greater not and detetcting. Perception not all or nothing more of a curved function as more intense the proabbilty increases. What is threshold needed to detect a sensation or stim. Bc giving part a standard set and keep on showing random intervals. Give them predefined light intensity and present 10 times and randomly and have respoind yes or no and compute average.