Advances in emerging technologies, such as on-body mechanical actuators and electrical muscle stimulation, have allowed computers to take control over our bodies. This presents opportunities as well as challenges, raising fundamental questions about agency and the role of our bodies when interacting with technology. To advance this research field as a whole, we brought together expert perspectives in a week-long seminar to articulate the grand challenges that should be tackled when it comes to the design of computers’ control over our bodies. These grand challenges span technical, design, user, and ethical aspects. By articulating these grand challenges, we aim to begin initiating a research agenda that positions bodily control not only as a technical feature but as a central, experiential, and ethical concern for future human–computer interaction endeavors.

Game studies and HCI research on embodied experiences and technology relationships often diverge; while game studies focus on the player–avatar relationship, HCI emphasises sensory perception and stimulation. This paper bridges these perspectives by examining movement as fundamental to perception and interaction, exploring how movement unfolds in sequences between player(s) and technologies. The paper presents a theoretical framework that combines the neuroscientific theories of predictive processing and active inference with phenomenology to understand perception and experience as subjective experiences along with their underlying neurobiological processes. Complemented by an autoethnographic inquiry in which the primary author played seven games over three years, we apply the theoretical framework to analyse how movement drives embodied experiences. Our findings reveal that the composition of movement sequences is a key mechanism for embodied player experiences and technology relationships. Furthermore, the study identifies four dynamics in the sequential movement compositions that shape the qualities of experience. By foregrounding movement as central to connecting players and avatars in sensory engagement, we provide a unified perspective that benefits researchers and designers across the fields of game studies and human-computer interaction (HCI).

• Presents a two-dimensional design space around body schema and body image for playful bodily extensions. • Details designers’ experiences creating playful bodily extensions. • Articulates practical strategies for the design of future playful bodily extensions. Interaction designers are increasingly interested in physically extending people's bodies and emerging work shows the potential of such bodily extensions for play, one example being interactive fantasy ears for the Cosplay community. We interviewed five designers of four playful bodily extensions to better understand how to design them. Based on their insights and our examination of prior work, we argue that such extensions can be characterized by the extent to which they alter the wearer's body schema and body image. We illustrate this characterization using a two-dimensional design space. We use this design space to articulate practical strategies for the design of future playful bodily extensions. Ultimately, we hope to bring more playful experiences to people's lives.

Interactive technologies offer novel opportunities for physically extending our bodies, with the most prominent examples being prosthetics along with systems emerging from the wearables community. However, most such systems appear to focus on instrumental benefits, missing out on the opportunity to use bodily extensions for play and its associated benefits (including a lower adoption barrier and the potential to reveal a broader understanding of such technologies). To begin understanding the design of playful bodily extensions, we interviewed five designers of bodily extensions that have been showcased in prestigious academic venues or turned into commercial products. Here we present themes and actionable advice from these interviews for the design of playful bodily extensions through a thematic analysis. Our work aims to support the design of future playful bodily extensions while promoting the experiential qualities of bodily extension design, with the ultimate goal of bringing more playful experiences to people’s lives.

Human–computer integration is an HCI trend in which computational machines can have agency, i.e., take control. Our work focuses on a particular form of integration in which the user and the computational machine share agency over the user's body, that is, can simultaneously (in contrast to a traditional turn-taking approach) control the user's body. The result is a user experience where the agency of the user and the computational machine is so intertwined that it is often no more discernable who contributed what to what extent; we call this “intertwined integration”. Due to the recency of advanced technologies enabling intertwined integration systems, we find that little understanding and documented design knowledge exist. To begin constructing such an understanding, we use three case studies to propose two key dimensions (“awareness of machine's agency” and “alignment of machine's agency”) to articulate a design space for intertwined integration systems. We differentiate four roles that computational machines can assume in this design space (angel, butler, influencer, and adversary). Based on our craft knowledge gained through designing such intertwined integration systems, we discuss strategies to help designers create future systems. Ultimately, we aim at advancing the HCI field's emerging understanding of sharing agency.

This paper presents restraints - directly imposed restrictions on players' bodily movements, as a mechanic for bodily play in HCI. While this is a familiar mechanic in non-digital movement-based games, its potential in designing bodily play experiences in HCI has been scarcely explored. Three types of restraints observed in non-digital movement-based games, are explored here: fixating body parts, excluding body parts and depriving/manipulating bodily senses. Then, we investigate the experiential dynamics of restraints as a bodily play mechanic bridging a phenomenological perspective on bodily movement with theories on play. These investigations form the theoretical framework for the subsequent analysis of five digital body game examples. Building on this analysis and theoretical framework, we formulate five design strategies for implementing restraints as a mechanic for bodily play in HCI. We propose restraints as a generative resource for researchers and designers interested in understanding and designing bodily play experiences in HCI.

Bodily play systems are becoming increasingly prevalent, with research aiming to understand the associated player experience. We argue that a more nuanced lexicon describing "bodily play experience" can be beneficial to drive the field forward. We provide game designers with two German words to communicate two different aspects of experience: "Erfahrung", referring to experience where one is actively engaged in and gains knowledge from; and "Erlebnis", referring to a tacit experience often translated as "lived experience". We use these words to articulate a suite of design strategies for bodily play experiences by referring to past design work. We conclude by discussing these two aspects of experience in conjunction with two previously established perspectives on the human body. We believe this more nuanced lexicon can provide a clearer understanding for designers about bodily play allowing them to guide players in gaining the many benefits from such experiences.