Why We Play Games: Four Keys to More Emotions Without Story is the name of the research undertaken by Nicole Lazzaro's XEODesign. You can read a summary here or the .pdf version here.
The reason I'm posting this link is the connection (pointed out by Chris) between that work and the topics being discussed here lately. Interestingly, Nostalgia, the term used by Hoofin Dan to describe the effects of Rail Simulator, is not listed among the Emotions During Play described on the paper.
The article, considered by Will Wright as the "most informative talk at GDC ", is well worth reading.