Randall Parker at FuturePundit discusses research that suggests that being in love makes it harder for a person to assess the degree of emotional involvement of other couples. As he puts it:
People who were in love and other people who were not in love were asked to view film clips of couples interacting who were in different levels of emotional involvement. The viewers who were in love were least able to identify which viewed couples were in love.
But this isn’t surprising, is it? After all, if you fully committed to your partner, you don’t need to know how committed other people are to their partners.
All that I know is that for more than ten years now, I have been completely, absolutely, insanely, head-over-heels, totally without a clue about the levels of emotional involvement of other couples.
Found via Marginal Revolution.