ERIC Number: EJ863072
Record Type: Journal
Publication Date: 2009-Dec
Abstractor: As Provided
Reference Count: 0
A Truncated-Probit Item Response Model for Estimating Psychophysical Thresholds
Morey, Richard D.; Rouder, Jeffrey N.; Speckman, Paul L.
Psychometrika, v74 n4 p603-618 Dec 2009
Human abilities in perceptual domains have conventionally been described with reference to a threshold that may be defined as the maximum amount of stimulation which leads to baseline performance. Traditional psychometric links, such as the probit, logit, and "t", are incompatible with a threshold as there are no true scores corresponding to baseline performance. We introduce a truncated probit link for modeling thresholds and develop a two-parameter IRT model based on this link. The model is Bayesian and analysis is performed with MCMC sampling. Through simulation, we show that the model provides for accurate measurement of performance with thresholds. The model is applied to a digit-classification experiment in which digits are briefly flashed and then subsequently masked. Using parameter estimates from the model, individuals' thresholds for flashed-digit discrimination is estimated.
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A