  The phenomenon of phase synchronization of oscillatory systems arising out of
feedback coupling is ubiquitous across physics and biology. In noisy, complex
systems, one generally observes transient epochs of synchronization followed by
non-synchronous dynamics. How does one guarantee that the observed transient
epochs of synchronization are arising from an underlying feedback mechanism and
not from some peculiar statistical properties of the system? This question is
particularly important for complex biological systems where the search for a
non-existent feedback mechanism may turn out be an enormous waste of resources.
In this article, we propose a null model for synchronization motivated by
expectations on the dynamical behaviour of biological systems to provide a
quantitative measure of the confidence with which one can infer the existence
of a feedback mechanism based on observation of transient synchronized
behaviour. We demonstrate the application of our null model to the phenomenon
of gait synchronization in free-swimming nematodes, C. elegans.
