This paper presents the results of an experiment in humanrobot social interaction. Its purpose was to measure the impact of certain features and behaviors on people’s willingness to engage in a short interaction with a robot. The behaviors tested were the ability to convey expression with a humanoid face and the ability to indicate attention by turning towards the person that the robot is addressing. We hypothesized that these features were minimal requirements for effective social interaction between a human and a robot. We will discuss the results of the experiment (some of which were contrary to our expectations) and their implications for the design of socially interactive robots.