## 3 The Human Role in Teleoperation  
A teleoperated system can be seen as a control loop, as in Figure 1, where the operator plays the role of selecting the appropriate signals and acts on the controlled element to execute the desired task. The task can be one of following a trajectory, a pick-and-place operation, or a much more complicated one. As in any control loop, the objective is to have the system follow some reference signal, and that is accomplished by comparing that input signal with some measurable observation of the system output. As the operator plays the role of the controller, he/she needs to receive the information about the system variables that he/she intends to control [28; 29]. Frequently, the information received is very limited and corrupted by different types of noise. It is here that humans normally play still irreplaceable roles given their ability to make correct inferences from incomplete data. Humans can still extract the necessary information in the presence of the most variable conditions, where typically automated mechanisms can only be tuned to specific working conditions and fail if these conditions are not met. Humans have the ability to use temporal signals, to build mental image mosaics, and to use them to make and execute plans [9]. This comes with a price: it is very hard to follow a memorized plan and simultaneously keep track of multiple information sources. In fact, the required concentration level induces important fatigue, and as it rises, it reduces our attention and concentration capabilities. Humans have some difficulties in noticing changes in slowly varying stimuli even if their intensity is high [30]. Actually, the exposure to the same stimuli for some period of time induces a process of desensitization where a constant or repetitive stimuli loses importance and becomes progressively integrated as part of the \"background\". On the other side, we are particularly good at learning automated skills; thus, operations like driving a car become simple reactive tasks where the conscious level is mostly left for the high-level plan, whereas lane keeping, velocity control, distance to other vehicles, etc., are performed mostly at the subconscious (reactive) level. It is well known that the reactive execution is simpler and less \"energy consuming\" than tasks that require reasoning. Similarly, the reactions to well distinguishable visual, auditory, or tactile stimuli generate much less fatigue than being focused on the detection of minor changes of the same stimuli. We are equipped with a set of complementary sensing mechanisms that together enable us to pay attention to most of the important events in our lives with minimum effort. For example, although the human eyes only produce high resolution information at their fovea, to minimize the amount of normal processing workload, their peripheral vision can detect sudden changes and motion. These motion field-generated stimuli, as well as auditory stimuli are enough to direct the visual attention to the right spot in the surrounding space when needed. This means that although we frequently browse the surrounding areas around us, we rely more on particular event detection to attract and direct our attention, instead of using any type of constant and exhaustive scanning process. This has indeed two main advantages: it saves energy and allows performing focused tasks while still being able to detect nearby events, in particular those that may represent any type of danger and thus require immediate action. Figure 1: A remote control loop schema (top). A modified control loop where an operator visualizes the intended reference and remote signals to generate the control signals to operate the remote device (bottom). Why are the above questions important when we are talking about teleoperation-based tasks? When we talk about executing tasks, we always define, implicitly or explicitly, success goals or success criteria.