The researchers began their investigation by having 19 people keep a diary of their nostalgia activities for 30 consecutive days. It turned out that the participants indulged in more nostalgic reverie on colder days.
Next, the psychologists recruited 90 undergrads in China and sat some of them in a cold room (20 degrees Celsius), some in a room at a comfortable temperature (24 degrees), and some in a hot room (28 degrees). The students were asked to say how nostalgic they felt for things like "music" and "friends they'd known". The finding here was that students sat in the colder room tended to be more nostalgic (students in the comfortable and hot rooms didn't differ from each other).
read more: http://bps-research-digest.blogspot.com/2012/05/feeling-chilly-indulge-in-some.html. Also, see http://www.squidoo.com/how-to-exercise-the-brain