Dipper function Flashcards
Who used the 2 AFC to obtain webers law for luminance discrimination?
Cornsweet and pinsker (1965)
When are gradient consistent with Webers law?
When both axes have same logarithmic scale , then any line withg a gradient of 1 wil be consistent with webers law
Otherwise all other gradient are inconsistent with webers law
When does the data no longer produce the dip?
When its background luminance that is varied and what is measured is the just detectable increment
Whgat was the task of Raab et al?
detect brief incriments in the amplitude of continuous auditory noises of varies intensity
What do large background noises do?
Usually make it harder to hear quite increments,
What is the effect of background noises called
Effect is called masking
What is negative masking
Describes power of just detectable increment decreasing as background noise increases from 0
What is random Fluctuation?
Noise
Explain power of noise?
Power of noise and its energy are both proportional to the pressure variance
What happenes if power is 0
Amplitude is also 0
How do you measure contrast or amplitude of a sample of visual noise ?
root mean squared luminance
How do you measure the amplitude of sample of auditory noise?
Root squared pressure
How do you measure total power?
Total power of background plus just noticeable increase in power
What is the just noticeable increment?
Difference between the total amplitude and that of the background alone
What does the retina do ?
Might absorb some photons which could not be used for vision = Photosensitization
