Section: Research Program


Meso-dynamics relate to phenomena that arise during interaction, on a longer but still short time-scale. For users, it is related to performing intentional actions, to goal planning and tools selection, and to forming sequences of interactions based on a known set of rules or instructions. From the system perspective, it relates to how possible actions are exposed to the user and how they have to be executed (i. e., interaction techniques). It also has implication on the tools for designing and implementing those techniques (programming languages and APIs).

Interaction bandwidth and vocabulary

Interactive systems and their applications have an always increasing number of available features and commands due to e. g., the large amount of data to manipulate, increasing power and number of functionalities, multiple contexts of use.

On the input side, we want to augment the interaction bandwidth between the user and the system in order to cope with this increasing complexity. In fact, most input devices capture only a few of the movements and actions the human body is capable of. Our arms and hands for instance have many degrees of freedom that are not fully exploited in common interfaces. We have recently designed new technologies to improve expressibility such as a bendable digitizer pen  [36], or reliable technology for studying the benefits of finger identification on multi-touch interfaces [4].

On the output side, we want to expand users' interaction vocabulary. All of the features and commands of a system can not be displayed on screen at the same time and lots of advanced features are by default hidden to the users (e. g., hotkeys) or buried in deep hierarchies of command-triggering systems (e. g., menus). As a result, users tend to use only a subset of all the tools the system actually offers  [44]. We will study how to help them to broaden their knowledge of available functions.

Through this “opportunistic” exploration of alternative and more expressive input methods and interaction techniques, we will particularly focus on the necessary technological requirements to integrate them into interactive systems, in relation with our redesign of the I/O stack at the micro-dynamics level.

Spatial and temporal continuity in interaction

At a higher-level, we will investigate how such more expressive techniques affect users' strategies when performing sequences of elementary actions and tasks. More generally, we will explore the “continuity” in interaction. Interactive systems have moved from one computer to multiple connected interactive devices (computer, tablets, phones, watches, etc.) that could also be augmented through a Mixed-Reality paradigm. This distribution of interaction raises new challenges from both the usability and engineering perspectives that we obviously have to consider in our main objective of revisiting interactive systems  [43]. It involves the simultaneous usage of multiple devices and also the changes in the role of devices according to the location, the time, the task, contexts of use: A tablet device can be used as the main device while traveling, and it becomes an input device or a secondary monitor for continuing the same task once in the office; A smart-watch can be used as a standalone device to send messages, but also as a remote controller for a wall-sized display. One challenge is then to design interaction techniques that support seamless and smooth transitions during these spatial and temporal changes of the system in order to maintain the continuity of uses and tasks, and how to integrate these principles in future interactive systems.

Expressive tools for prototyping, studying, and programming interaction

Actual systems suffers from issues that keep constraining and influencing how interaction is thought, designed, and implemented. Addressing the challenges we presented in this section and making the solutions possible require extended expressiveness, and researchers and designers must either wait for the proper toolkits to appear, or “hack” existing interaction frameworks, often bypassing existing mechanisms. For instance, numerous usability problems in existing interfaces are stemming from a common cause: the lack, or untimely discarding, of relevant information about how events are propagated and changes come to occur in interactive environments. On top of our redesign of the I/O loop of interactive systems, we will investigate how to facilitate access to that information and also promote a more grounded and expressive way to describe and exploit input-to-output chains of events at every system level. We want to provide finer granularity and better-described connections between the causes of changes (e.g. input events and system triggers), their context (e.g. system and application states), their consequences (e.g. interface and data updates), and their timing [8]. More generally, a central theme of our Interaction Machine vision is to promote interaction as a first-class object of the system  [33], and we will study alternative and better adapted technologies for designing and programming interaction, such as we did recently to ease the prototyping of Digital Musical Instruments [1] or the programming of animations in graphical interfaces [10]. Ultimately, we want to propose a unified model of hardware and software scaffolding for interaction that will contribute to the design of our Interaction Machine.