This article presents a video-based field study of the Reactable, a tabletop tangible user interface (TUI) for music performance, in a hands-on science centre. The goal was to investigate visitors’ social interactions in a public setting. We describe liminality and cross-group interaction, both synchronous with fluid transitions and overlaps in use between groups and asynchronous. Our findings indicate the importance of: (i) facilitating smooth transitions and overlaps between groups and (ii) supporting not only synchronous but also asynchronous group interaction. We discuss the lessons learned on how best to enable liminal situations in the design of interactive tabletops and TUIs for social interaction and particularly collaborative tangible music in public museum settings.

There has been little research on how interactions with tabletop and Tangible User Interfaces (TUIs) by groups of users change over time. In this article, we investigate the challenges and opportunities of a tabletop tangible interface based on constructive building blocks. We describe a long-term lab study of groups of expert musicians improvising with the Reactable, a commercial tabletop TUI for music performance. We examine interaction, focusing on interface , tangible , musical, and social phenomena. Our findings reveal a practice-based learning between peers in situated contexts, and new forms of participation, all of which is facilitated by the Reactable's tangible interface, if compared to traditional musical ensembles. We summarise our findings as a set of design considerations and conclude that construction processes on interactive tabletops support learning by doing and peer learning, which can inform constructivist approaches to learning with technology.

When electronic musicians compose collaboratively, they typically use their own single-user musical controllers. It may, therefore, be useful to develop novel controllers that support collaborative workflows and democratic principles. After describing the design principles for developing such controllers, we present TOUCHtr4ck, a prototype multi-touch system designed to facilitate such democratic relationships. Informal testing has revealed that this approach does facilitate democratic and collaborative music making, and can produce creative musical results.

This paper presents DENN, a dynamic neural network or neural substrate having a number of abilities that might allow it to play a useful role as a constituent of an artificial cognitive system, handling the task of low-level perceptual processing. DENN can adapt without supervision to new objects, is able to respond to patterns of activation from several objects presented simultaneously to it, and is able to automatically switch its perception between multiple objects. It is based on an ideal neural substrate as conjectured by Dimond (1980), having the twin capabilities of autonomous learning and memory, capabilities emerging due to the use of autonomous neurons. DENN has a pyramidal architecture and its neurons have topologically organized receptive fields. Through training, the neurons become feature detectors, with the higher level neurons responding to more complex features. The neurons respond to a retinal input with an oscillatory output whose frequency depends only on their own input. Due to developing phase differences, the higher level neurons can move out of phase relative to each other. Therefore, different inputs are recognized cyclically-a process we term 'automatic perception switching'. Experiments verified the system's ability of automatic perception switching, investigated its response to randomized images, and compared the performance of adaptive and non-adaptive versions of the neural substrate.