  Similar formalisms have been independently developed in psychology, to deal
with the issue of selective influences (deciding which of several experimental
manipulations selectively influences each of several, generally
non-independent, response variables), and in quantum mechanics (QM), to deal
with the EPR entanglement phenomena (deciding whether an EPR experiment allows
for a "classical" account). The parallels between these problems are
established by observing that any two noncommuting measurements in QM are
mutually exclusive and can therefore be treated as analogs of different values
of one and the same input. Both problems reduce to that of the existence of a
jointly distributed system of random variables, one variable for every value of
every input (in psychology) or every measurement on every particle involved (in
an EPR experiment). We overview three classes of necessary conditions (some of
them also sufficient under additional constraints) for the existence of such
joint distributions.
