Research Report Dual-tasking: Is manual tapping independent of concurrently executed saccades? Megi Sharikadze a,b, ⁎ , Dung-Khac Cong a , Gerhard Staude a , Heiner Deubel c , Werner Wolf a a Institute of Communication Engineering, University of Federal Armed Forces, Werner-Heisenberg-Weg 39, Neubiberg 85579, Germany b Department of Behaviour and Cognitive Functions, I. Beritashvili Institute of Physiology, Gotua St. 12, Tbilisi 0160, Georgia c Department of Psychology, Ludwig-Maximilians University, Leopold St. 13, Munich 80802, Germany ARTICLE INFO ABSTRACT Article history: Accepted 28 May 2009 Available online 6 June 2009 Maintaining both spatial and temporal accuracy of concurrent motor actions is a challenging behavioral requirement in multi-tasking, where possible resource bottlenecks may become apparent when these units are shared between tasks. This study addresses the question of whether periodic self-paced finger movements (tapping) compulsorily interact with concurrently executed saccades, because they share some common neural control pathways. We employed a dual-task paradigm which was previously used to demonstrate strong interference between independent but concurrently conducted bimanual tapping tasks (Wachter, C., Cong, D.K., Staude, G., Wolf, W., 2008. Coordination of a discrete response with periodic finger tapping, additional experimental aspects for a subtle mechanism. J. Motor Behav. 40, 417–432). Instead of the discrete left hand response, the 13 participants now executed a single saccadic eye movement to a fixed visual target in parallel to continuous periodic tapping of the dominant hand. We expected these reactive saccades to act as a strong perturbation event to the continuous tapping, but the experimental data did not reveal a considerable interference in this specific oculo-manual dual-task experiment. © 2009 Elsevier B.V. All rights reserved. Keywords: Index finger tapping Saccade Dual-task Interaction 1. Introduction A fascinating example of multi-tasking is the one-man band — this musical tradition demonstrates the amazing capability of humans to execute several parallel actions with reliable spatio-temporal accuracy, which requires a high degree motor coordination between different effectors. The coordi- native process is so naturally governed by the central nervous system that many of our daily multi-tasking activities seem to be effortless and easy. However, while musicians are trained to perform more than one task simultaneously, normal individuals dealing with some dual- or multi-tasking are usually troubled; e.g., bimanual interference is found when two manual tasks are conducted concurrently (e.g., Swinnen and Wenderoth, 2004). Dual-task costs (i.e., decreased perfor- mance in comparison to isolated execution of the tasks) were found not only in bimanual but also in other dual-task combinations (Pashler et al., 1993; Sigman and Dehaene, 2008). Favoring a serial organization of sensorimotor trans- formation stages (perception, cognition and action) within a single channel, some researchers (Welford, 1967; Pashler, 1994; Pashler and Johnston, 1989) attributed dual-task costs to a central bottleneck at the response-selection stage, which is assumed to be generic (e.g., Hazeltine and Ruthruff, 2006), whereas others (Logan and Gordon, 2001; Navon and Miller, 2002) addressed the limitations of strategic allocation of the BRAIN RESEARCH 1283 (2009) 41 – 49 ⁎ Corresponding author. Institute of Communication Engineering, University of Federal Armed Forces, Werner-Heisenberg-Weg 39, Neubiberg 85579, Germany. Fax: +49 89 6004 3603. E-mail addresses: meg.sharikadze@unibw.de, msharikadze@mac.com (M. Sharikadze). 0006-8993/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2009.05.065 available at www.sciencedirect.com www.elsevier.com/locate/brainres