  A human operator using a manual control interface has ready access to their
own command signal, both by efference copy and proprioception. In contrast, a
human supervisor typically relies on visual information alone. We propose
supplying a supervisor with a copy of the operators command signal,
hypothesizing improved performance, especially when that copy is provided
through haptic display. We experimentally compared haptic with visual access to
the command signal, quantifying the performance of N equals 10 participants
attempting to determine which of three reference signals was being tracked by
an operator. Results indicate an improved accuracy in identifying the tracked
target when haptic display was available relative to visual display alone. We
conjecture the benefit follows from the relationship of haptics to the
supervisor's own experience, perhaps muscle memory, as an operator.
