Questions and Answers
A more sophisticated goal of the 19th century psychophysicists was to obtain mathematical formulas that would specify the precise relationship between the __________ of a physical stimulus and the __________ of the resulting sensation.
intensity; magnitude
What was Fechner's early attempt to quantify the relationship between stimulus intensity and perception called?
Fechner's Law
Who achieved an accurate psychophysical law in the 1950s?
S.S. Stevens
What psychophysical technique did Stevens use that involves assigning a numerical value to a standard stimulus?
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What sensory dimensions did Stevens use the magnitude estimation procedure for?
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What is the formula known as Steven's Power Law?
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What does P represent in Steven's Power Law?
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What does k stand for in Steven's Power Law?
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What does S stand for in Steven's Power Law?
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What does n represent in Steven's Power Law?
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If the exponent n < 1, what does it mean?
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This kind of relationship between stimulus intensity and subjective sensation is called _____________ and enables many of our sensory systems to function effectively across a vast range of stimulus intensities.
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If the exponent n > 1, what does it indicate?
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What is the relationship called when a small increase in intensity leads to serious damage in terms of sensation?
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Another sensory dimension showing response expansion is ________, where detecting the presence of nutrients and poisons is crucial for survival.
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An exponent n = 1 means there is a ________________________. This is very rare but occurs, as one would expect, for simple visual judgments of line length.
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Study Notes
Relationship Between Stimulus and Sensation
- Psychophysicists sought to establish mathematical formulas linking the intensity of physical stimuli to the magnitude of resulting sensations.
- Fechner introduced an approximation of this relationship, known as Fechner's Law.
Development of Steven's Power Law
- The accurate psychophysical law was formulated in the 1950s by S.S. Stevens.
- Stevens employed a technique called magnitude estimation, where subjects assigned numerical values to stimuli in relation to a standardized stimulus set at 100.
Applications of Magnitude Estimation
- Magnitude estimation was applied across various sensory dimensions: weight, loudness, brightness, taste, smell, temperature, and painful electric shock.
Steven's Power Law Formula
- The relationship is expressed mathematically as P = kSn, where:
- P represents perceived magnitude of sensation.
- k is a constant influenced by the chosen units of measurement.
- S denotes stimulus intensity.
- n is an exponent varying with sensory dimensions.
Understanding the Exponent (n)
- An exponent n < 1 indicates response compression; substantial increases in stimulus only cause minor changes in sensation (e.g., brightness, loudness).
- An exponent n > 1 signifies response expansion, where small increases in intensity lead to significant increases in sensation, as seen in painful electric shocks.
- Response expansion is crucial for survival, especially regarding harmful stimuli or detecting nutritional compounds in taste.
Linear Relationships
- An exponent n = 1 reflects a linear relationship between the stimulus intensity and sensation magnitude, which is rare but observable in basic visual tasks like judging line lengths.
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Description
Explore the fundamental concepts of Stevens Power Law through this set of flashcards. Test your understanding of the mathematical relationships between physical stimuli and sensory perception. Perfect for psychology students seeking to deepen their knowledge of psychophysics.
