Original Article

Psychological Research

, Volume 75, Issue 2, pp 77-94

First online:

On quantifying multisensory interaction effects in reaction time and detection rate

  • Stefan RachAffiliated withDepartment of Psychology, University of OldenburgJacobs University Bremen Email author 
  • , Adele DiederichAffiliated withJacobs University Bremen
  • , Hans ColoniusAffiliated withDepartment of Psychology, University of Oldenburg

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Both mean reaction time (RT) and detection rate (DR) are important measures for assessing the amount of multisensory interaction occurring in crossmodal experiments, but they are often applied separately. Here we demonstrate that measuring multisensory performance using either RT or DR alone misses out on important information. We suggest an integration of RT and DR into a single measure of multisensory performance: the first index (MRE*) is based on an arithmetic combination of RT and DR, the second (MPE) is constructed from parameters derived from fitting a sequential sampling model to RT and DR data simultaneously. Our approach is illustrated by data from two audio–visual experiments. In the first, a redundant targets detection experiment using stimuli of different intensity, both measures yield similar pattern of results supporting the “principle of inverse effectiveness”. The second experiment, introducing stimulus onset asynchrony and differing instructions (focused attention vs. redundant targets task) further supports the usefulness of both indices. Statistical properties of both measures are investigated via bootstrapping procedures.


Audio–visual interaction Redundant target paradigm Inverse effectiveness Sequential sampling model Inverse efficiency scores Multisensory performance enhancement