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oai:docta.ucm.es:20.500.14352/449102023-08-28T06:51:39Zcom_20.500.14352_14col_20.500.14352_15
Docta Complutense author García Pérez, Miguel Ángel author Alcalá Quintana, Rocío 2023-06-20T04:05:56Z 2023-06-20T04:05:56Z 2011 1943-3921 10.3758/s13414-011-0167-x https://hdl.handle.net/20.500.14352/44910 http://dx.doi.org/10.3758/s13414-011-0167-x http://link.springer.com/journal/13414 Proportion correct in two-alternative forcedchoice (2AFC) detection tasks often varies when the stimulus is presented in the first or in the second interval.Reanalysis of published data reveals that these order effects (or interval bias) are strong and prevalent, refuting the standard difference model of signal detection theory. Order effects are commonly regarded as evidence that observers use an off-center criterion under the difference model with bias. We consider an alternative difference model with indecision whereby observers are occasionally undecided and guess with some bias toward one of the response options. Whether or not the data show order effects, the two models fit 2AFC data indistinguishably, but they yield meaningfully different estimates of sensory parameters. Under indeterminacy as to which model governs 2AFC performance, parameter estimates are suspect and potentially misleading. The indeterminacy can be circumvented by modifying the response format so that observers can express indecision when needed. Reanalysis of published data collected in this way lends support to the indecision model. We illustrate alternative approaches to fitting psychometric functions under the indecision model and discuss designs for 2AFC experiments that improve the accuracy of parameter estimates, whether or not order effects are apparent in the data. eng Interval bias in 2AFC detection tasks: sorting out the artifacts journal article URL https://docta.ucm.es/bitstreams/6e425891-e51e-4df9-aabc-20c933617649/download File MD5 e96fd02032e7274b1e3b5af529b14542 1054187 application/pdf Interval RAlcalá.pdf