Mulder, M. J. , Forstmann, B. U. & Wagenmakers, E.
Department of Psychology, University of Amsterdam, Plantage Muidergracht 24, 1018TV Amsterdam, The Netherlands
Research in perceptual decision making is dominated by paradigms that tap the visual system. For example, a popular paradigm used to measure the speed and accuracy of a perceptual decision is the random-dots motion (RDM) task. In this task, participants have to decide quickly whether a ʻcloudʼ of dots is moving to the left or to the right on a computer screen. Although this two-alternative forced choice task has proven to be extremely useful to study simple decision processes, results are limited to the visual modality. To investigate whether the underlying dynamics of perceptual decisions apply to the auditory field as well, we developed an auditory version of the RDM paradigm where tones correspond to dots and pitch corresponds to motion. Psychophysical features underlying the auditory stimulus were kept similar to those used in the visual task. We will show that the stimulus strength of the random-tones pitch (RTP) task has a similar effect on the speed and accuracy of a perceptual decision. Furthermore, by combining the two tasks we will be able to investigate the effects of simultaneously presented audio and visual stimuli on the decision process. Results will help understand how humans use information from different modalities to optimize their choice behavior.