A user study is presented that investigates how different configurations of input can influence equity of participation around a tabletop interface. Groups of three worked on a design task requiring negotiation in four interface conditions that varied the number (all members can act or only one) and type (touch versus mice) of input. Our findings show that a multi-touch surface increases physical interaction equity and perceptions of dominance, but does not affect levels of verbal participation. Dominant people still continue to talk the most, while quiet ones remain quiet. Qualitative analyses further revealed how other factors can affect how participants con tribute to the task. The findings are discussed in terms of how the design of the physical-technological set-up can affect the desired form of collaboration.