Faye Wu, a mechanical engineering graduate student at MIT, said in a video about the project that the fingers take the input from a sensor glove… that can measure the position of the human fingers. Then, an algorithm controls the output of the robotic add-ons using the position of the human fingers, as determined by the sensors. MITs 7 finger robot seems promising, but right now, the robotic hand more closely resembles a well designed science project than a product you would actually want to use regularly.