Proceedings of the Annual Meeting of the Cognitive Science Society

Trials in a two-alternative forced-choice (2AFC) recognition-memory task require individuals to choose the stimulus in apair that they deem as having been previously studied. Be-cause of the relative nature of the judgments made, 2AFC tri-als are typically considered to be free from response biasesconcerning the old/new status of stimuli. Recent studies havesuggested that this assumption is incorrect, and individuals of-ten resort to single-stimulus old-new (ON) judgments instead.The present study tests this claim by joint modeling 2AFCand ON judgments using extended SDT models that includethe possibility of ON contamination. Results show that therelative-judgment assumption provides an excellent account ofthe data, providing no support for the notion of ON contami-nation in typical experimental designs.