[Evaluation of three sensitivity measures in magnitude estimation tasks]

Area of Science:

• Psychophysics
• Sensory Perception
• Quantitative Psychology

Background:

• Magnitude estimation tasks are crucial for understanding sensory perception.
• Evaluating sensitivity measures in these tasks is essential for accurate data interpretation.
• Common measures include Pearson's correlation (R), Stevens' power function exponent (K), and Garriga-Trillo's measure (M).

Purpose of the Study:

• To critically analyze and compare the efficacy of three common sensitivity measures in magnitude estimation.
• To determine the most reliable measure for quantifying sensitivity in psychophysical studies.
• To provide evidence-based recommendations for selecting sensitivity measures.

Main Methods:

• An experiment was conducted with 180 participants, a larger sample than typical for psychophysical studies.
• Two sets of stimuli with varying ranges and two types of stimuli (line segments and squares) were used.
• The performance of Pearson's correlation (R), Stevens' power function exponent (K), and Garriga-Trillo's measure (M) was evaluated.

Main Results:

• The exponent of Stevens' power function (K) yielded results contrary to expectations when comparing different stimulus ranges, leading to its rejection.
• Garriga-Trillo's measure (M) was rejected due to its nature as a linear transformation of Kendall's coefficient of concordance.
• Fisher's transformation, applied to Pearson's correlation (R), demonstrated suitability for achieving a normal distribution.

Conclusions:

• Stevens' power function exponent (K) and Garriga-Trillo's measure (M) are not recommended as reliable sensitivity measures in magnitude estimation.
• Fisher's transformation of Pearson's product-moment correlation (R) is proposed as the optimal method for assessing sensitivity.
• This recommended measure offers improved reliability and interpretability in psychophysical research.