Because Nathaniel and Olivia have kept their friendship strong despite the inevitable disagreements and irritations of married life, they are experiencing what is known technically as “positive sentiment override,” or PSO, a concept first proposed by University of Oregon psychologist Robert Weiss. This means that their positive thoughts about each other and their marriage are so pervasive that they tend to supersede their negative feelings. It takes a much more significant conflict for them to lose their equilibrium as a couple than it would otherwise.
