MMB-MusicPerception_1b_Psychoacoustics Flashcards
- What does psychoacoustics aim to do?
Psychoacoustics aims to quantify the relationship
between an auditory stimulus and its percept
- Describe two steps to psycho-acoustical experiments:
- Vary stimulus parameter (eg intensity or frequency) and
- Observe how human perception / responses change
- What 5 elements make up Components of psycho-acoustical experiments?
- Stimulus
- Task
- Mehtod
- Analysis
- Measure
- Give an example to detrmine hearing thresholds with Method of limits.
Stimuli: Pure sine tones
• Task: Forced-choice task‘Do you hear it?’ (Y/N)
• Method: In-/decrease intensity for subsequent trials
(Method of Limits)
• Analysis: Record for each intensity level whether
stimulus was detected or not and compute average
(detection rate) for each level
• Measure: Hearing Threshold, i.e. intensity level at given
detection rate (e.g. 50% or 75%)
- What is the reality of detecting a stimulus multiple times?
There is a variabliity:
Sometimes you hear it; sometimes you don’t due to various sources of error, e.g. ‘variability of brain activity’ (Solomon, 1900) or ‘of perceptual processes’ (Thurstone, 1927)
- Describe the Method of Limits.
In ascending method of limits, some property of the stimulus starts out at a level so low that the stimulus could not be detected, then this level is gradually increased until the participant reports that they are aware of it.
The decending method of limits reverses this.
- What is the detection threshold?
An detection thershold or **absolute threshold **is the level of intensity of a stimulus at which the subject is able to detect the presence of the stimulus some proportion of the time (a p level of 50% is often used)
- Discuss problems with the Method fo Limits.
• Trials are given in a systematic order and participants
might form expectations (errors of habituation and
expectation)
• Participants might have individual bias to respond ‘yes’
or ‘no’
- Describe
2-alternative forced choice task which is an alternative to **Method of limits. **
• Participant needs to detect feature in one of two stimuli
presented and responds ‘1’ or ‘2’
• Feature can be e.g. mistuning, specific frequency in
complex sound, higher pitch.
• Stimuli with and without feature are presented randomly
at position 1 or 2
- 3-Alternative forced choise task (3AFC) is known as what?
- 3AFC (‘odd-one-out’) paradigm: Present more than 2 stimuli and participants indicate which one was different to the others (i.e. carried the feature)
- Other variants: ‘same-different’ response, match to sample response
- A number of alternative choice tasks (nAFC)
Draw a graph of possible combinations.
- Describe the adaptive method: Staircase.
•Parameter of interest (eg intensity) is varied across X
levels
•Order of presentation of these levels is determined by the
participant’s response
– Starts easy, gets harder as long as performance correct
– Incorrect response trial leads to a ‘reversal’: the subsequent trial is one level easier
– Set maximum number of ‘reversals’
•Threshold determined by finding the average level of the
last X reversals
- Draw a diagram illustrating a siple up-down staircase
- Describe **Running Fits. **
•Select stimulus at most likely threshold level, based on
responses so far (procedures MLP, PEST, QUEST)
- Give an example of a complex tone frequency discrimination thershold experiment. List the following stages.
- Stimuli
- Task
- Method
- Analysis
- Measure
- Stimuli: Complex sine tones
- Task: 3AFC ‘which tone is highest?’ (1,2,3)
- Method: running fit stimulus selection at perceptual threshold
- Analysis: Fit psychometric function to response data using maximum likelihood estimation
- Measure: Hearing threshold at perceptual ‘sweet point’ (72.9% correct responses)
- **Classifying psycho-acoustical experiments. **
Question
1 What is the goal of the experiment?
Performance measure:
Do we want a point meassure?
Hearing thershold?
Something where there is a wrong and write answer
or subjective perceptual Appearance:
No definite right or wrong answers but the answers can give a pattern of information to try and find patterns in more subjective questions like “What does typical progressive rock music sound like?”
- Classifying psycho-acoustical experiments.
Question 2
What kind of measure do you want to obtain?
Threshold v Scale v …
Scale of progeressive Rock for example.. Pink Floyd on 5 and another band on 1..
- Classifying psycho-acoustical experiments.
Question 3
•What kind of task??
Forced-choice v non-forced-choice (e.g. adjustment)
19.
Classifying psycho-acoustical experiments.
Question 4
How many stimuli presented on each trial??
N=1, N=2, N=3, …
20.
Classifying psycho-acoustical experiments.
Question 5
•What kind of response and how many response options to
choose from?
Yes/No v same-different v odd-one out v …
- Draw a graph laying out a psycho-acoustical experiment as (Kingdon and Prins, 2010).
- Example study:
Describe
Influence of frequency on
loudness perception
• Goal: Investigate loudness appearance (no
right/wrong answers)
• Measure: Points of Subjective Equality
• Task/Procedure: Method of Adjustment:
– Give participants reference stimulus (e.g. sine tone at
1kHz and 40dB)
– Ask them to produce an equally loud stimulus at
different frequency (e.g. 1.5kHz) by turning an
intensity dial
• Analysis: Average the produced intensities
across all participants
=> Curves of equal loudness
- What is psychoacoustics good for?
Attributes of physical stimuli are mapped onto
perceptual dimensions: Equal-loudness curves
- Which task/method to use?
Depends on:
• Goal of experiment
• Types of desired measure
• Type of stimuli
• Time constraints
• Participants’ range of skills
• Expected participants’ bias
- Excercise
Classify the ‘Melodic Memory’ and the ‘Beat
Perception’ tests of the Gold-MSI (Müllensiefen
et al., 2014, Plos One, Study 4) according to - Goal
- Type of measure
- Task
- Number of stimuli
- Type of response
- Number of response options
GO LOOK IT UP
Perception’ tests of the Gold-MSI (Müllensiefen
et al., 2014, Plos One, Study 4)
