If I were to ask you, "How is your life going?" chances are that, as you try to formulate an answer, you soon come to think of other people in an attempt to arrive at some kind of judgement. "Am I happy?"—I don't know, how happy are those around me? "Is my career going well?"—hmm, how successful are other people? Psychologically, it is difficult for us to judge how things are—including how we ourselves are—without making comparisons. We are quite poorly equipped to judge the state of things—including our lives—in absolute terms, and will often make use of various reference points. That is, we engage in comparisons to arrive at judgments. There are many ways in which we do this from a psychological perspective.
I love psychoanalysis of literary texts, and Jane is definitely a psychologist (I dare say few writers are above her on this area). Great article :)