PSYCHOACOUSTICS: Introduction to Psychophysics Flashcards
What are Fechner’s four major contributions?
1) Formalized the concept of a threshold
2) Weber-Fechner’s Law
3) Introduced the concept of sensation equivalence
4) Formalized 3 psychophysical techniques (“Classical psychophysical methods”)
method of adjustment
explain how Fechner Formalized the concept of a threshold
Formalizing the concept of a threshold: Fechner’s work helped to formalize the idea of thresholds in psychology, particularly the concept of absolute and difference thresholds.
what is Weber’s law?
Weber-Fechner’s Law states that the just-noticeable difference between stimuli is proportional to the magnitude of the stimuli. It means that as the intensity of a stimulus increases, it takes a greater change to produce a noticeable difference in sensation. For instance, when comparing sizes of circles, the pair with the smallest difference in size may be hardest to distinguish if the others have larger differences.
What does the concept of sensation equivalence propose?
Sensation equivalence suggests that the mental representation of a physical stimulus can be quantified mathematically.
How is the point of subject equality (PSE) defined?
The PSE refers to any point along a stimulus dimension where a variable stimulus is perceived to be equal to a standard stimulus by an observer.
Who extended the concept of sensation equivalence and what hypothesis did they propose?
Urban extended the concept, proposing that the PSE increases logarithmically with stimulus intensity based on Fechner’s hypothesis.
Can you provide an example of sensation equivalence in practice?
In loudness perception experiments, researchers set a standard stimulus, such as a 40-dB SPL 1kHz tone, and determine at what sound level another tone, like a 250-Hz tone, is perceived equally loud as the standard tone.
What are the concepts related to JND and PSE?
In experiments where people judge the length of lines, the smallest difference reliably discerned is termed the just noticeable difference (JND), while the average length perceived as equal is known as the point of subjective equality (PSE).
How is precision related to the JND?
Precision is considered high when the JND is small, indicating that individuals can discriminate subtle differences in stimuli effectively.
What does accuracy refer to in relation to the PSE?
Accuracy is high when the PSE closely aligns with the actual value, indicating that individuals accurately perceive the stimuli.
What is perceptual scaling?
Perceptual scaling involves understanding the relationship between the intensity of a stimulus and the magnitude of perception.
Define the interval or level of uncertainty.
The interval or level of uncertainty refers to the range of values of the comparison stimulus, typically the JND just above and just below the PSE, where the comparison stimulus cannot be reliably discriminated from the standard stimulus.
Is there typically a linear relationship between stimulus intensity and perception magnitude?
No, typically there isn’t a linear relationship between stimulus intensity and perception magnitude.
What is meant by a prothetic continuum?
A prothetic continuum refers to perceptual experiences that involve an underlying aspect of intensity or magnitude, allowing us to compare and quantify sensations.
How do perceptions with a prothetic continuum differ from others?
Perceptions with a prothetic continuum allow us to ask questions about intensity or magnitude, enabling comparisons along a scale of intensity. This is in contrast to other perceptions where such comparisons may not be meaningful or feasible.
What is a metathetic continuum?
A metathetic continuum refers to perceptual experiences where differences between stimuli can be perceived, but it’s not meaningful or possible to assign a numerical value to those differences.
e.g.
It doesn’t make sense to ask if a “red” hue is more or less than a “green” hue. More or less what???
How do perceptions with a metathetic continuum differ from those with a prothetic continuum?
Perceptions with a metathetic continuum lack the ability to assign numerical values to differences between stimuli, unlike perceptions with a prothetic continuum where quantification along a scale of intensity or magnitude is possible.
What are the three classical psychophysical methods?
The three classical psychophysical methods are the method of adjustment, the method of limits, and the method of constant stimuli.
Can you explain the method of adjustment?
In the method of adjustment, the participant controls the stimulus directly, adjusting it until it matches the perceived sensation.
What is the method of limits?
The method of limits presents stimuli in ascending or descending order until the participant detects a change, allowing researchers to determine thresholds.
What does the method of constant stimuli involve?
In the method of constant stimuli, a set of stimuli, including some above and below the threshold, are presented randomly to the participant to determine their ability to detect the stimulus.
What is the difference between absolute threshold and difference threshold?
The absolute threshold is the minimum intensity of a stimulus required for it to be detected, while the difference threshold (or just noticeable difference, JND) is the smallest difference in stimulus intensity that can be detected.
How do detection and discrimination tasks relate to absolute and difference thresholds?
- Detection tasks involve determining whether a stimulus is present or absent, related to the absolute threshold.
- Discrimination tasks involve distinguishing between two stimuli, linked to the difference threshold or JND.
What is the point of subjective equality (PSE) in psychophysics?
The point of subjective equality (PSE) is the average stimulus level at which a participant perceives two stimuli as being equal, often determined in discrimination tasks.
How are JND, PSE, precision, and accuracy related?
JND represents the smallest detectable difference, while PSE signifies the perceived equality point. Precision refers to the consistency of measurements, often high when JND is small, while accuracy reflects how closely PSE aligns with actual values.
