Abstract: In order to effectively support collaboration it is important that computer technology seamlessly support users' natural interactions instead of inhibiting or con-straining the collaborative process. The research presented in this paper examines the human-human component of computer supported cooperative work and how the design of technology can impact how people work together. In particular, this study examined children's natural interactions when working in a physical medium compared to two computer-based environments (a traditional desktop computer and a system augmented to provide each user with a mouse and a cursor). Results of this research demonstrate that given the opportunity, children will take advantage of the ability to interact concurrently. In addition, users' verbal interactions and performance can be constrained when they are forced to interact sequentially, as in the traditional computer setup. Supporting concurrent interactions with multiple input devices is a first step towards developing effective collaborative environments that support users' natural collaborative interactions.