Universidad Complutense de Madrid
E-Prints Complutense

Fixed vs. variable noise in 2AFC contrast discrimination: lessons from psychometric functions.



Downloads per month over past year

García Pérez, Miguel Ángel and Alcalá Quintana, Rocío (2009) Fixed vs. variable noise in 2AFC contrast discrimination: lessons from psychometric functions. Spatial vision, 22 (4). pp. 273-300. ISSN 0169-1015

[thumbnail of Fixed vs variable noise in 2AFC contrast discrimination  Alcalá Quintana.pdf] PDF
Restringido a Repository staff only


Official URL: http://dx.doi.org/10.1163/156856809788746309.


Recent discussion regarding whether the noise that limits 2AFC discrimination performance is fixed or variable has focused either on describing experimental methods that presumably dissociate the effects of response mean and variance or on reanalyzing a published data set with the aim of determining how to solve the question through goodness-of-fit statistics. This paper illustrates that the question cannot be solved by fitting models to data and assessing goodness-of-fit because data on detection and discrimination performance can be indistinguishably fitted by models that assume either type of noise when each is coupled with a convenient form for the transducer function. Thus, success or failure at fitting a transducer model merely illustrates the capability (or lack thereof) of some particular combination of transducer function and variance function to account for the data, but it cannot disclose the nature of the noise. We also comment on some of the issues that have been raised in recent exchange on the topic, namely, the existence of additional constraints for the models, the presence of asymmetric asymptotes, the likelihood of history-dependent noise, and the potential of certain experimental methods to dissociate the effects of response mean and variance.

Item Type:Article
Uncontrolled Keywords:Transducer model, 2AFC, Contrast, Discrimination, Psychometric function, Signal detection theory, Nise variance, Detection
Subjects:Medical sciences > Psychology > Experimental psychology
ID Code:35698
Deposited On:16 Sep 2016 09:59
Last Modified:16 Sep 2016 10:14

Origin of downloads

Repository Staff Only: item control page