Cool study, but WTF is this gift:
In one study, undergraduate students were asked to imagine giving or receiving a birthday gift of a pint of ice cream that would arrive on time or two weeks late.
Who gifts a pint of ice cream? It has to be constantly cooled to stay frozen, you can't wrap it and put it under a tree, nevermind having it shipped. I'd file that under "I brought a snack, let's eat it".