Birthdays are meant to be special events—days you spend with friends, family, and loved ones. They are a celebration of growing another year older, and a reflection on one’s life thus far.

My 19th birthday was last week, and with it came the realization that I have one more year of life as a “teen” before I turn 20, and I truly enter the realm of adulthood. I’ll admit, a part of me was panicky at the thought.

A birthday marks a time to reflect on accomplishments and changes experienced in the past year. However, this reflection brings a measure of disappointment.

What about all of those goals I did not reach? Were those changes really for better, or for worse? What might have been the potential outcomes, if I had made different choices?

Curious, I delved into the history, science, and psychology of birthdays. Why do we celebrate our day of birth, and what are the implications?

Unraveling the psychology of birthdays begins with the view of children. A study of children aged three to five revealed that many children directly link the concept of a birthday party to aging.

When told about a child who had two birthday parties one year, nearly a third of the children incorrectly assumed the child had grown two years older. Additionally, if someone did not have a birthday party, 71% of the children believed that person would remain the same age.

We know this is silly; the practice of birthday parties obviously do not cause aging. However, birthday parties are a cultural event, which obviously affects the way children perceive biological growth.

Heather Ulrich, Assistant Professor of Psychology at UNC Asheville, explains, “Children come to depend on these events for consistency and continuity in their lives,” and celebrating birthdays helps children understand “aging each year...[and] what each age means and its developmental significance.”

Still, analyzing the impacts of birthdays as a cultural event raises even more questions.

According to researchers from The University of Pennsylvania, birthdays are akin to “temporal landmarks”. Basically, as important life events, birthdays mark an invisible boundary between our current and future selves.

Psychological research further supports this claim, indicating that birthdays can represent this division between the past and future, in terms of achievements and goals.

Temporal landmarks have a positive correlation with motivation and encourage goal-oriented behavior. In terms of birthdays specifically, this translates to motivation to attain the improvements we perceive our future selves will have.

Birthdays also carry significant cultural relevance. Psychologists largely debate the significance of the ritual rites of passage that accompany major life events or transitions, and whether these rites of passage are connected to an altered state of consciousness.

According to Ruth Benedict, renowned anthropologist, American culture lacks a defined cultural transition from childhood to adulthood. However, psychohistorian Janice Klein, argues that birthday parties can serve as life course rituals that support transitory growth.

Each birthday represents new rights and a step towards adulthood— a milestone to mark a “meaningful juncture in time.”

It is true that birthdays, for some people, are meaningful and memorable days of festivity and bonding with loved ones. However, other people do not experience birthdays as celebratory occasions.

In fact, many experience a distinct lack of joy regarding their birthday; instead, they are wracked with anxiety and depression. The term coined for these feelings is "birthday blues," and these emotions can arise for various reasons.

One cause is the denial of aging. No one can control or slow down the aging process, and therefore, another year older becomes a feared and dreaded correlation to another year older. In a way, it starts to seem like life is passing us by much too quickly.

Another contributing factor is the stress of accomplishments. There is an underlying pressure to achieve enough in a year that it is worth celebrating.

When we feel unsatisfied with our accomplishments, or believe we have not fulfilled our own expectations, it is difficult to feel happy about another year past.

Now that I am 19 years old, I understand the "birthday blues" that accompany a day that should be happy and celebratory. It is easy to wonder how much more I could have achieved in this past year if I had worked harder or made different decisions.

However, it is important to mitigate those feelings with the reality of what I did accomplish. The goals I have not reached this past year will simply translate to those I will tackle in the future.

As I leave my teenage years behind, I feel prepared for adulthood, and the different experiences I will face. Another year older, but another year wiser!