It’s the most wonderful time of the year, and many curious minds ask, why? The holidays seem to be quite an emotional time of year, filled with singing, happiness, tears of both joy and sadness, and even everyone’s favorite mind-killers, fear and anxiety. Of course, there is no law stating that the last two months of the year must be filled with celebration, so what exactly is it that makes a bearded guy falling down a chimney the main event of the year? Much of the wonder of the festive season comes from our very own brains, which are just as magical as any Christmas creature.

One of the first major end-of-year holidays is Thanksgiving, which is fuelled by our neuropsychology and social natures just as much as Christmas is. Much of this holiday is based on tradition, social expectations, and nostalgia. A lot has changed since the very first Thanksgiving dinner as family traditions have evolved around technological and economical advances. Still, however, tradition has always played a major role in the “magic” of the holiday season. Participating in festive traditions often leads to a surge of serotonin, dopamine, and oxytocin (reward and love chemicals) in the brain, which trains us to continue these habits year after year. While “training” implies that the human tendency to follow holiday tradition is tantamount to a dog following an owner’s command in exchange for a treat and a surge of oxytocin, there are much more complicated factors that go into creating the joyous atmosphere of the holidays.

Many people’s first thought upon the mention of Thanksgiving is of food – a table laden with turkey, stuffing, mashed potatoes, buttered rolls, pies – is your mouth watering yet? Mouth-watering results from the brain’s reaction to the sight, smell, or sometimes mere mention of food. The brain reacts quite strongly to the Thanksgiving feast, and the anticipation and preparation leading up to it. Preparation itself (especially of food) often leads to feelings of satisfaction and well-being as a result of the release of dopamine in the brain.

Much of the holiday joy also comes from nostalgia, that indescribable feeling of simultaneous sadness and joy that often accompanies remembrance. Nostalgia is not fully understood by science, although it is known to be largely based in the limbic system (hippocampus, amygdala, hypothalamus, and thalamus), with involvement from many other parts of the brain. Thanksgiving favorites, for example, often bring about nostalgic memories, which further contribute to food’s impact on the sentimental atmosphere surrounding the holidays.

Food is only one of the major associations with the festive season, with family most often being the other. Positive interactions between family members and even pets during the holiday season increase oxytocin levels in the brain, leading to feelings of well-being and warmth within a household. Family also encourages tradition, and those performing these traditions with family members often derive more pleasure from them than those engaging in the same activities alone, again most likely due to oxytocin, although this is not always the case.

Caroling is one of the most well-known signs that the winter holidays are upon us, as music can be one of the most powerful harbingers of emotion. fMRI (functional magnetic resonance imaging) and EEG (electroencephalography) studies of patients while listening to music reveal that almost the entire brain is activated by music, particularly the limbic system and temporal lobes. Christmas music is often particularly emotional, as Christmas itself is sentimental and nostalgic. In fact, Oliver Sacks, well-known neurologist, observed several patients suffering temporal lobe seizures in which they would hear loud music, often linked to emotional memories. Many of these patients did not feel as if they were suffering at all, and still listened to Christmas carols on repeat, which may indicate the extent of these songs' influence on the brain.

Just as Christmas carols play an essential part in Christmas spirit, Christmas lights and decorations are also key to the season. These decorations, too, are integral to tradition. Without these, it would never truly look like Christmas – and for many, seeing is believing. Christmas wouldn’t be the same without mistletoe and holly. Many enjoy the holiday scents, which are also quite nostalgic. The olfactory cortex (located in the temporal lobes) is close to the hippocampus, which is why scent often brings about powerful memories.

The holiday season isn’t always pure joy, however. The Christmas blues, which are so common there are even songs about them, can snuff out the Christmas spirit and lead to anxiety and isolation from depression. Christmas blues can be caused by anything, although some common causes include loneliness and seasonal depression, a potential result of the shortening of days which occurs near the start of the holidays. Anxiety can often run wild during the holidays as well, as adults scramble frantically to make their houses and kids festive, and kids anxiously anticipate two straight weeks with no school and all family. While some of the symptoms of these issues can be treated relatively easily with mindfulness, gratitude, and support from available friends and family, many still suffer from Christmas blues.

Even so, the Christmas season is a magical time of year, largely because of the number of magic tricks your brain pulls off in order to give you the experience. None of this is intended to ruin the enchanting warmth of the holidays, of course. Just remember: when expressing gratitude during Thanksgiving, thank your brain, especially your hippocampus and temporal lobes, for allowing you to enjoy the wonder of the season.

Information from The Man who Mistook His Wife for a Hat, by Oliver Sacks; Wikipedia, National Institutes of Health, Psychology Today, and Harvard Medical School