Attraction tends to arrive without warning. It appears in exchanged glances at the gym, during a laugh that comes a little too easily or in moments when your heart feels like it is moving faster than your thoughts. The intensity can feel sudden and unexplainable, even when nothing about the interaction seems extraordinary.
Despite how mysterious it feels, attraction is not random. Psychologists suggest it is not a checklist of traits but an interaction between biology, context and perception. Rather than being a single spark, attraction reflects how people think and feel about others, often before they realize it themselves.
“(It is) the force that brings people together; it can be one-sided and it could be two-sided,” said Sara Garvey, psychology instructor at Colorado State University. “It can be motivational, meaning it propels us towards someone else, whether that’s romantic, sexual, platonic or professional.”
Subtle cues shape that force. Jennifer Harman, an associate professor of psychology at CSU, explained that unconscious signals, personal goals, similarities and culture influence attraction.
“There has been a lot of research looking at physical features such as facial symmetry, fertility indicators like age and body proportions, and personality traits,” Harman said. “Even someone who may be average in appearance can be rated as more attractive if they are intelligent, funny or emotionally engaging.”
Researchers have long studied facial symmetry as a key component of physical attraction. People often perceive symmetry as both beauty and familiarity.
“The more symmetrical, the more we like it,” Harman said. “It feels familiar to us. It represents a combination of every other face we’ve seen, so it feels comfortable.”
While facial symmetry explains part of the pull, familiarity extends beyond physical features. Attraction is also rooted in perceived similarity. People tend to feel drawn to those who reflect something recognizable in themselves, whether that similarity appears in one’s personality, background, values or lifestyle.
“Attraction is influenced by a lot of factors working together. It depends on biology, culture, personal experience and what someone wants out of a relationship at a given point in their life.” -Jennifer Harman, CSU psychology associate professor
That sense of recognition causes people to gravitate toward partners who resemble past relationships, close friends or even family members. Comfort and compatibility often feel intertwined. As Garvey explained, similarity is not limited to appearance.
“Similarity (can exist) in terms of values, hobbies, preferences, lifestyle choices, behaviors, looks, age, educational background, socioeconomic background,” Garvey said. “If I had to pick the biggest factor that drives attraction, it would be similarity.”
Attraction also involves an ongoing process of self-evaluation. Have you ever found yourself more attracted to someone once you realized they were interested in you? Harman referred to this dynamic as a feedback loop.
“People get feedback over time,” Harman said. “Because of that feedback, they tend to pursue people they believe are at a similar level of attractiveness.”
Similarity may create comfort. Attraction, though, often begins at a more instinctive level, shaped by cues that are registered before conscious thought. These cues rarely feel analytical; they feel automatic — a glance across a classroom, a quickened heartbeat or sudden butterflies in your stomach before you can explain why.
Many of these automatic reactions are tied to subtle indicators of health and fertility. From an evolutionary perspective, traits associated with fertility signal potential for reproduction and long-term partnership. People may not consciously think about starting a family, but those cues still register. Features such as vocal tone, facial appearance and even scent can influence perceived attractiveness without deliberate awareness.
Attraction is also shaped by context. The setting where you meet someone can influence how that initial spark is experienced.
“If you’re at the gym and you see somebody who’s attractive, you’re going to rate them more attractive because you’re excited from working out.” Harman said.
When heart rate is already elevated, it becomes easier to confuse physiological arousal with romantic chemistry. What feels like desire may, at times, be excitement borrowed from the environment — a sensation that can level out as time passes.
Harman explained that while early attraction is often intense and immediate, long-term attraction can deepen through familiarity, shared experience and emotional closeness. The initial rush may soften over time, but it does not necessarily disappear. Brain-imaging studies show that people in long-term relationships continue to display attraction responses when viewing their partners. Even so, change is inevitable. Garvey noted that a decline in sexual attraction commonly occurs in long-term relationships.
“Within sexual attraction, it’s well-documented that in long-term relationships you can experience a decline, and it is seen as a natural phenomenon,” Garvey said. “It’s called the Coolidge effect.”
This phenomenon describes a decrease in novelty. As routines settle and partners become deeply familiar, the intense excitement of newness can fade. However, that shift does not automatically signal the end of desire.
“A lot of people assume that the decline of sexual attraction means that their relationship is doomed,” Garvey said. “But that is just a natural experience when you’ve been with the same person.”
Rather than viewing attraction as something that either survives or dies, Harman emphasized that it evolves.
“Attraction is influenced by a lot of factors working together,” Harman said. “It depends on biology, culture, personal experience and what someone wants out of a relationship at a given point in their life.”
Reach Scout Kingsley at science@collegian.com or on social media @RMCollegian.