As the days become shorter and the temperatures colder, the holiday season will cause many people to embrace nostalgia over the past year or past holidays. Researchers have found that reminiscing about the Good Old Days may have a physiological benefit as well - nostalgia seems to help keep us warm.

The study consisted of several experiments that tested this hypothesis. Conducted by researchers from the University of Southampton, the experiments included volunteers from China and the Netherlands.

The first experiment asked volunteers to keep track of the days when they were feeling nostalgic over the course of a month. The researchers found that volunteers were more nostalgic on cooler days.

The second experiment placed volunteers in one of three rooms. The first room was 20 degrees Celsius or 68 degrees Fahrenheit, classified as the cold room. The second room was 24 degrees Celsius or 75 degrees Fahrenheit, classified as the comfortable room. The third room was 28 degrees Celsius or 82 degrees Fahrenheit, the hot room. Researchers found that, while there was no difference in nostalgia between the comfortable and the hot room, volunteers in the cold room reported feeling more nostalgic.

It may seem that these experiments prove simply that people feel more nostalgic when they are cold, rather than that nostalgia heats them up. However, the following studies are less ambiguous.

The third study, conducted online, involved music. Participants who said that the music made them feel nostalgic also reported feeling more physically warm.

The fourth study placed volunteers in a cold room. Participants were instructed to recall either a nostalgic event or an ordinary event from their pasts. Then they were asked to estimate the room temperature. Those who had recalled an event nostalgically guessed the room to be warmer than the other group.

The fifth and last study asked volunteers to recall either a nostalgic or ordinary event as well, while placing their hands in ice-cold water for as long as they could tolerate it. Those feeling nostalgic were able to stand the cold water for longer periods of time than the other group.

The study was published in the journal Emotion.