Models of Reaction Times in Auditory Lexical Decision - RTonset versus RToffset.

We investigate how the role of predictors in models of reaction times in auditory lexical decision experiments depends on the operational definition of RT: whether the time is measured from stimulus onset or from stimulus offset. In a large body of literature, RTs are measured from the onset of the stimulus to the start of the response (often a button press or an oral response). The rationale behind this choice is that information about the stimulus becomes available to the listener starting at onset. Alternatively, the RT from offset is less dependent on stimulus duration and is assumed to focus on those cognitive processes that play a role late(r) in the word and after word offset, when all information is available. The paper presents RT-onset and RT-offset-based linear mixed effects models for three different lexical decision-based data sets and explains the significant differences between these models, showing to what extent both definitions of reaction time reveal different roles for predictors and how early and later contributions to the overall RT can be differentiated.