title: To react or not to react? Intrinsic stochasticity of human control in virtual stick balancing.
abstract: Understanding how humans control unstable systems is central to many research problems, with applications ranging from quiet standing to aircraft landing. Increasingly, much evidence appears in favour of event-driven control hypothesis: human operators only start actively controlling the system when the discrepancy between the current and desired system states becomes large enough. The event-driven models based on the concept of threshold can explain many features of the experimentally observed dynamics. However, much still remains unclear about the dynamics of human-controlled systems, which likely indicates that humans use more intricate control mechanisms. This paper argues that control activation in humans may be not threshold-driven, but instead intrinsically stochastic, noise-driven. Specifically, we suggest that control activation stems from stochastic interplay between the operator's need to keep the controlled system near the goal state, on the one hand, and the tendency to postpone interrupting the system dynamics, on the other hand. We propose a model capturing this interplay and show that it matches the experimental data on human balancing of virtual overdamped stick. Our results illuminate that the noise-driven activation mechanism plays a crucial role at least in the considered task, and, hypothetically, in a broad range of human-controlled processes.
authors: University of Aizu, Tsuruga, Ikki-machi, Aizuwakamatsu, Fukushima 965-8580, Japan arkady.zgonnikov@gmail.com.
authors: Arkady
authors: A
authors: Zgonnikov
authors: University of Aizu, Tsuruga, Ikki-machi, Aizuwakamatsu, Fukushima 965-8580, Japan i-lubash@u-aizu.ac.jp.
authors: Ihor
authors: I
authors: Lubashevsky
authors: University of Aizu, Tsuruga, Ikki-machi, Aizuwakamatsu, Fukushima 965-8580, Japan.
authors: Shigeru
authors: S
authors: Kanemoto
authors: University of Aizu, Tsuruga, Ikki-machi, Aizuwakamatsu, Fukushima 965-8580, Japan.
authors: Toru
authors: T
authors: Miyazawa
authors: University of Aizu, Tsuruga, Ikki-machi, Aizuwakamatsu, Fukushima 965-8580, Japan.
authors: Takashi
authors: T
authors: Suzuki
mesh_terms: D001696:Biomechanical Phenomena; D005260:Female; D005717:Games, Experimental; D006801:Humans; D008297:Male; D008954:Models, Biological; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D013269:Stochastic Processes
keywords: control activation; human control; intermittency; stick balancing; stochastic modelling