With opportunities for human beings to coexist with artificial agents and autonomous robots are increasing, high-level interactive communication between them is increasingly needed. These human symbiotic systems are used for research on basic intelligent interaction design principles and methods and bidirectional communication based on effective collaboration and symbiosis between human beings and robots, agents, and computers, also known as artifacts.

The research society on gHuman Symbiotic System (HSS)h was implemented by the Japan Society for Fuzzy Theory and Intelligent Informatics (SOFT) in 2007. The HSS encourages academic and industrial discussion of research on Human-Agent Interaction (HAI), Human-Robot Interaction (HRI), and Human-Computer Interaction (HCI).

The objective of this special issue is to activate and expand top-quality research of HSS theory and applications. Reflecting the fact that this research covers a wide range of topics, we invited researchers from fields including intelligent robotics, human-machine interfaces, and Kansei engineering to contribute. This issue thus provides much of the latest practical research on HSS, introduced by core members of the research society.

Of the 22 papers received, 14 were accepted after input from two reviewers each. The first paper, by Y. Tamura et al., presents an attentive deskwork support system that delivers required items objects to deskworkers. The second, by H. Masuta et al., discusses an integrated perceptual system for intelligent service robots. The third, by S. Akiguchi, develops an automatic pattern generation system based on user impression. The fourth, by Y. Jiang et al., deals with a novel interface recognizing directional user intent based on forearm pressure exerted by the user of an omnidirectional walker.

The fifth paper, by K. Terabayashi et al., investigates effects of preoperation on the experience of hands of different sizes by classifying preoperations based on the hand/object relationship. The sixth, by Y. Tamura et al., proposes segmenting a performerfs body imitating behavior observed based on a system from which values are obtained by reinforcement learning. The seventh, by D. Katagami et al., discusses group-adaptive behavior based on utterance contents and social standing of a robot. The eighth, by H. Yamaguchi et al., presents a system for using discounted utterances in spontaneous conversations applying text-mining technology.

The ninth paper, by A. Otaki et al., focuses on the development of human negotiation skill through interaction between human players and computer agents in bargaining games. The tenth, by D. Katagami et al., is also related to human negotiation skill implementing human gestures in negotiation scenarios for three negotiation agents. The eleventh, by R. Taki et al., realizes interactive emotion communication - bidirectional communication based on emotional behavior between human beings and robots. The twelfth, by J. Ichino et al., investigates the psychological effects of color on online documents through a proposed online document interface.

The thirteenth paper, by T. Ando et al., studies the robot facial effectiveness in human interpretation. The fourteenth, by T. Ando et al., models robot self-sufficiency applying an urge system focusing on autonomous emotion.

This issue has addressed the importance of HSS and highlighted innovative approaches to the development of artificial system more friendly to users. We thank the authors and referees for their ongoing efforts, without which this issue would not have been possible.