Psychophysics #3

Question	Answer
Image: JktFQ (image/png)	Signal detection analysis. 2x2 square.
Image: Picture2 (image/png)	Method of constant stimuli used to discover difference thresholds for heaviness
Image: Picture3 (image/png)	A normal ogive
UT is found where on a normal ogive function?	At the 75% mark (>/=50% subjective reporting of heavier than standard).
LT is found where on a normal ogive?	At the 25% mark (>/=50% subjective reporting of lighter than standard).
Difference Threshold (DT) is what?	DT=UT-LT/2 DT=101-97/2 DT=2
Point of Subjective Equality (PSE) is what?	at 50% on a normal ogive. It is the weight which is subjectively reported as being equal in weight to the stardard weight
Webers law?	∆I = kI ∆I = DT I = stimulus intensity/magnitude of standard stimulus. k = the constant
Weber's fraction	k = ∆I/I
Weber's fraction for weight =	2%
DT of a 20kg wieght is?	k=2%/0.02 I=20,000 grams ∆I=kI ∆I=0.02x20,000 ∆I=400grams
JND of a 20kg weight is?	Just noticeable difference is JND=I+∆I JND=20+.4 JND=20.4kgs
Webers fractions and sensitivity	The smaller the fraction the more sensitive, the bigger the fraction the less sensitive. Fractions - Brightness>Heaviness>Electric - 8%>2%>1% Sensitivity - Electric>Heaviness>Brightness

Resource summary

	Created by cjjstone over 11 years ago