Preemptive Action

Accelerating Human Reaction Using Electrical Muscle Stimulation Without Compromising Agency

Shunichi Kasahara (Sony CSL), Jun Nishida (The University of Chicago), Pedro Lopes (The University of Chicago)

We enable preemptive force-feedback systems to speed up human reaction time without fully compromising the user's sense of agency. Typically these interfaces actuate by means of electrical muscle stimulation (EMS) or mechanical actuators; they preemptively move the user to perform a task, such as to improve movement performance.

Unfortunately, when using preemptive force-feedback users do not feel in control and loose their sense of agency. We address this by actuating the user's body, using EMS, within a particular time window, which we found to speed up reaction time by 80 ms in our first study. With this preemptive timing, when the user and system move congruently, the user feels that they initiated the motion (sense of agency), yet their reaction time is faster than usual.

This is a collaborative research project with Jun Nishida and Pedro Lopes (The University of Chicago).

Talk / Presentation

The full paper about this project has been accepted to ACM CHI 2019. We will give a talk at CHI 2019 (May 4-9) at Glasgow, Scotland Uk,

Shunichi Kasahara, Jun Nishida, and Pedro Lopes. 2019. Preemptive Action: Accelerating Human Reaction using Electrical Muscle Stimulation Without Compromising Agency, In CHI Conference on Human Factors in Computing Systems Proceedings (CHI 2019), May 4-9, 2019, Glasgow, Scotland Uk. ACM, New York, NY, USA, 15 pages. (DOI link will be available in April)

Related Work

Jun Nishida, Shunichi Kasahara, and Kenji Suzuki. 2017. Wired muscle: generating faster kinesthetic reaction by inter-personally connecting muscles. In ACM SIGGRAPH 2017 Emerging Technologies (SIGGRAPH '17). ACM, New York, NY, USA, Article 26, 2 pages. DOI:

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