  The notion of symbiosis has been increasingly mentioned in research on
physically coupled human-machine systems. Yet, a uniform specification on which
aspects constitute human-machine symbiosis is missing. By combining the
expertise of different disciplines, we elaborate on a multivariate perspective
of symbiosis as the highest form of physically coupled human-machine systems.
Four dimensions are considered: Task, interaction, performance, and experience.
First, human and machine work together to accomplish a common task
conceptualized on both a decision and an action level (task dimension). Second,
each partner possesses an internal representation of own as well as the other
partner's intentions and influence on the environment. This alignment, which is
the core of the interaction, constitutes the symbiotic understanding between
both partners, being the basis of a joint, highly coordinated and effective
action (interaction dimension). Third, the symbiotic interaction leads to
synergetic effects regarding the intention recognition and complementary
strengths of the partners, resulting in a higher overall performance
(performance dimension). Fourth, symbiotic systems specifically change the
user's experiences, like flow, acceptance, sense of agency, and embodiment
(experience dimension). This multivariate perspective is flexible and generic
and is also applicable in diverse human-machine scenarios, helping to bridge
barriers between different disciplines.
