Psychophysics: Detection Flashcards
(34 cards)
What 5 things does a person do with a sound?
1.) Detection
2.) Discrimination
3.) Localization
4.) Identification
5.) Comprehension
Who was Gustav Fechner?
Inventor of psychophysics in the 1800s
What is psychophysics?
The mapping of a physical characteristic of a stimulus to a psychological percept
What are the 3 elements of psychophysics?
1.) Method of constant stimuli
2.) Method of limits
3.) Method of adjustment
What are the 2 problems associated with the method of limits?
1.) Error of habituation
2.) Error of anticipation
What is Bekesy Tracking?
Von Bekesy takes the method of limits and cleans it up. Brings a person in and sits them down and starts with a loud sound and go down. As soon as the person can’t hear it, take the level up until they can hear it again, then bring it down again, then bring it up, repeat. Tracks the reversal points where the person changes their response and is closer to their threshold. Averages these reversal points.
What was the problem with the method of limits?
These methods are not efficient because you spend a lot of time presenting sounds that are too loud/soft and not actually near their threshold. Wasting everyone’s time.
What is Weber’s Law?
Change in a stimulus / reference stimulus = constant percentage
What is the problem that threshold presents?
Should hearing always be a yes/no response 100% of the time? You either hear it or you don’t….
What is Signal Detection Theory?
A framework that allows you to separate a person’s sensitivity from their response bias
What can affect response biases?
Priming or external motivations
What can affect a person’s response to not make it yes/no 100% of the time?
1.) Physiological noise
2.) Spontaneous firing of auditory neurons
How does SDT measure sensitivity?
It is the distance between the means of the distributions (signal, signal+noise)
In SDT, if a signal was presented and you say yes, it is a ____
Hit
In SDT, if a signal was presented and you say no, it is a ___
Miss
In SDT, if a signal was not presented and you say yes, it was a ___
False Alarm
In SDT, if a signal was not presented and you say no, it is a ___
Correct Rejection
What is D-Prime?
The measure of sensitivity
d’=mean(SN) - mean(N)
How would you apply the concepts of SDT to create a test?
1.) Good sensitivity by having a high hit rate; it detects a disorder when it is actually present
2.) Good specificity by having a low false alarm rate; it does not detect a disorder when there is none present
What 5 things does the smallest sound a person can hear depend on?
1.) How you make the measurement
2.) Duration of the sound
3.) Continuous vs intermittent sounds
4.) Frequency of sound
5.) The question you’re asking
In what range are afferent fibers most dense?
1000-4000Hz
What is afferent innervation density?
The place where afferent fibers are most dense and multivesicular. The 1000-4000Hz range
Why are intermittent sounds better than continuous sounds?
If an intermittent tone is presented, it has a lot of onset and gives more detectable cues (onset bursts) to the person and better detection of a sound.
What is temporal summation?
The perceived loudness of a sound increases as its duration lengthens, meaning the longer a sound lasts, the louder it seems, especially when the sound is short in duration
Essentially, the ear integrates the sound energy over time, leading to a stronger neural response with longer stimulus presentation