  Recently, Bohr's complementarity principle was assessed in setups involving
delayed choices. These works argued in favor of a reformulation of the
aforementioned principle so as to account for situations in which a quantum
system would simultaneously behave as wave and particle. Here we defend a
framework that, supported by well-known experimental results and consistent
with the decoherence paradigm, allows us to interpret complementarity in terms
of correlations between the system and an {\em informer}. Our proposal offers
formal definition and operational interpretation for the dual behavior in terms
of both nonlocal resources and the couple work-information. Most importantly,
our results provide a generalized information-based trade-off for the
wave-particle duality and a causal interpretation for delayed-choice
experiments.
