Life is like a train, with companions boarding and alighting at each station.
Close friends who stuck together daily during student days may drift apart after graduation; once-thought-to-be-lifelong confidantes may grow distant as life trajectories diverge, gradually becoming "like" acquaintances in social media. Some feel disheartened, others accept it with equanimity. So, is friendship truly episodic?
The United Nations Educational, Scientific and Cultural Organization (UNESCO) designates July 30th as the "International Day of Friendship," initially aiming to call on people to cherish interpersonal connections. Psychological research, however, has long revealed: the "episodic" nature of friendship is not a regret but a medal of growth—"Friendship, in essence, is a flower blooming from the soul at different life stages."
"Episodic" is the destined form of most friendships.
Why Does Friendship Have an "Episodic" Nature?
Friend-selection criteria evolve with the awakening of self-awareness.
Developmental psychologist Robert Selman tracked changes in children's friendships over years and proposed the famous "Five-Stage Model of Friendship Development." For example, children aged 3-7 take "playing with toys together" as the entirety of friendship; by 9-11, "sharing secrets" becomes the keyword, as children confirm each other's uniqueness. After 12, friendship criteria "upgrade" to pursuing spiritual resonance—children discuss in their own language whether "friends understand me" or "do we share the same values."
This change is no accident. As children grow, they gradually realize that friends are not just playmates but "extensions of another self." For instance, a 15-year-old girl may distance herself from friends who only talk about cartoons and instead get closer to classmates who can discuss the future, emotions, and other topics. Friend-selection criteria evolve with the awakening of self-awareness.
Erik Erikson's psychosocial development theory divides human life into eight stages, each with a core task. For example, adolescence's task is "self-identity" (Who am I?), early adulthood is "intimacy" (establishing stable relationships), and so on. These "life tasks" directly influence individuals' needs for friends.
For example, young adults just entering university have more opportunities to try new travels, courses, and romantic relationships. They are more likely to choose friends to explore with, reflecting on "what kind of person I am" through interactions. Meanwhile, employed adults with families expect more support from friendships—they retain friends with whom they can share and discuss work relations, parenting anxieties, and other practical issues. By retirement age, friends to reminisce about the past and exchange life experiences become important, as the loneliness from declining physical functions is filled by such enduring friendships. The "episodic" nature of friendship is essentially a result of needing "different tools" at different life stages.
Social Penetration Theory compares relationship development to "peeling an onion": two people start from the outermost layer of "interests and hobbies" (e.g., discussing recent movies), gradually deepen to "attitudes and values" (discussing views on marriage), and finally touch on "private selves" (sharing childhood traumas or financial pressures). Ideally, friendships also go through a process from superficial to deep, evolving from "polite acquaintances" to "knowing each other thoroughly."
Interestingly, Social Penetration Theory also reveals that deeply developing friendships are often a dynamic, balanced, two-way effort. If one party rushes to advance the relationship (e.g., asking about income or love history soon after meeting), it may push the other away; if both parties remain "superficial," the friendship may stay at "like" acquaintances forever.
British anthropologist Robin Dunbar's cognitive limit theory of social relationships suggests that humans can maintain stable interpersonal relationships with a ceiling of about 150 people, including colleagues, friends, and other acquaintances, but excluding long-uncontacted casual acquaintances. Though subsequent studies dispute the exact number (ranging from 100-250), the core view is widely accepted—human socializing has a natural "cognitive ceiling," and relationship quality matters more than quantity.
Even with effort, it's hard to retain all friends. When entering new environments (e.g., changing jobs, moving), the brain automatically "cleans up" the social list—prioritizing relationships relevant to the new environment, while old ones may be "pushed out." This is not indifference but a "survival strategy" for efficient brain functioning.
Social Comparison Theory points out that humans naturally assess their value by comparing with others. This comparison is particularly subtle in friendships: when a friend gets promoted, married, or has children while we remain "stagnant," we may unconsciously feel distanced; conversely, if we fare better, we may worry "will the friend be jealous?" Upward comparison triggers anxiety, while downward comparison may show superiority. Either way, it may weaken friendship intimacy, leading to gradual estrangement.
Many believe friendship should be everlasting, making "episodic" friendship regrettable.
But this is not the case—whether parting or walking together, the friendships we truly had in life shape us in different ways.
Developmental psychologist Urie Bronfenbrenner's ecological systems theory holds that human growth is influenced by multiple environments, including family, school, and peers, with the role of peers not to be underestimated. Different types of friends expose us to varied problem-solving styles and interaction patterns, influencing us in multiple ways. Even when a friendship ends, it may hint, in some way, "this relationship is no longer suitable."
Sociologist Charles Cooley's "looking-glass self" theory suggests that people's self-cognition largely comes from others' feedback. Friends act as mirrors—their attitudes and evaluations help us see "who I am." The episodic changes in friendship are essentially a dynamic evolution of this "mirror interaction."
Moreover, human social skills are not innate but acquired through continuously adjusting friendship models. "Playful friendships" in childhood teach cooperation and sharing; "soulful friendships" in adolescence cultivate empathy and understanding; "supportive friendships" in adulthood exercise responsibility and tolerance.
"Every meeting has a reason—either a blessing or a lesson." Whether comparing friendship to a boat or a train, people walk together because their "life paths" temporarily intersect; separation often means different directions and destinations. What matters is that during the shared journey, both became better selves.
Achieving This: Episodic Friendships Can Also Be "Multidimensionally Maintained"
Low-frequency, high-quality interaction: Often, occasional, unexpected contact between friends can deepen feelings more than frequent daily greetings. For example, sharing an article related to your friend's career with a note like "This perspective reminded me of you" sends a signal of "I'm thinking of you."
Friendship time capsule: Memories strengthen emotional bonds. Keep old photos, chat screenshots, travel tickets, or "bestie" T-shirts bought together. These items are not for "nostalgia" but to remind yourself "this friendship once truly existed."
Nurturing new relationships: The "episodic" nature of friendship also means we always have opportunities to start new chapters. Joining interest communities, volunteering, or inviting colleagues for coffee are all chances to meet new friends. Building new friendships doesn't require "deliberate catering" but finding "people on the same frequency."
Enjoying "light friendships": "Quiet normally, shining at critical moments"—in fast-paced life, this lightweight social style is more like a "half-cooked" soft-boiled egg. "Partners" for meals, travel, etc., are representatives of such "light friendships." These precisely matched "light friendships" make interpersonal interactions more diverse and inclusive.
