To examine the impacts of enhanced UI feedback on shoulder-to-shoulder computing, we conducted a study using a simple picture puzzle on a computer with one display, two mice, and one keyboard. After adding sound, color differentiation, status indicators, and a graphical history, the accuracy with which subjects reported the actions of the person sitting next to them increased significantly. Participants also took more time to complete the puzzle. Subjects shared the keyboard more when using the enhanced UI. We also found participants sitting to the left of the screen to be considerably more productive across both UIs.