In his Oscar-nominated performance in Call Be By Your Name, the young actor Timothée Chalamet finishes the film with a striking act of catharsis. To say much more about what surrounds the moment would be to spoil it, but importantly, as the credits roll, Chalamet stares into the camera, inviting the viewer to share in the intimacy. There’s a good chance that upon watching, you’ll also share the small glints of tears Chalamet sheds on-screen.

There’s also a good chance that Call Be Your Name wasn’t the only movie selected by the Academy this year that made you cry. Films like The Shape of Water and Lady Bird pressed on the emotions of its viewers, asking them to empathize with both the joy and pain portrayed on screen.

Why you cry at the movies isn’t an exact science, but there is real science behind it. An actor’s ability to bring in real feeling ignites emotional cues driven by evolution.

Humans actually shed three types of tears: basal tears, released when you blink from small glands under the eyelid; reflexive tears that wash away irritants like onions; and big wet, never-ending emotional tears released through our lacrimal glands. The ability to weep emotional tears appears to be distinctively human. The exact function of emotional crying isn’t completely understood, and just as emotional tears are unique to humans, the purpose of crying is unique to the person doing it.

Scientists say crying serves two broad categories of function: How crying affect an individual (the intra-individual function) and the effect crying has on others, which in turn goes back to affecting you in some way (the inter-individual function).

As anybody who’s been a teenager probably knows, there have been a handful of rigorous scientific studies that have found that the result of a good cry is mood enhancement and stress reduction. Crying is cathartic.

The drive to experience catharsis may be why some people seek out tear-jerkers, says Jonathan Rottenberg, Ph.D., the Director of the Mood and Emotion Lab at the University of Southern Florida.

Going to the movies, Rottenberg tells Inverse, allows people “experience ordinarily painful experiences in a safe controlled way, without the usual negative consequences.”

How much a person cries at the movies is largely a consequence of a their capacity for empathy.

This empathetic capacity, seems to develop during adolescence, says Ad Vingerhoets, Ph.D., a professor of clinical psychology at Tilburg University. As one of the world’s experts on the psychology of crying, he tells Inverse that he wonders if adult emotional crying, ignited by stimuli like a movie or ASPCA commercial, also has a relationship to our memories of our first time being in love, which in turn makes us hyper-aware of how we care for others when we see something emotional play out on screen.

“Probably the strongest elicitors of tears are losses and separations — the death of intimates, romantic breakups, homesickness,” Vingerhoets tells Inverse. “Interestingly, as we grow older, we also see those seemingly opposite situations [cause tears]. The bonds that become stronger, including acts of altruism, self-sacrifice, comradeship, also become very powerful elicitor of tears.”

Interestingly, these tear-jerking concepts often help actors enter an emotional state that allows them to give an Oscar-winning performance. Numerous actors I spoke to said that to get in the right headspace for an emotional scene they have to pull from their own lives — some, imagining giving an eulogy for a parent, while another would reread a breakup letter when that pain was still fresh.

Actress Ivy Dupler says that she tries to pull from a “sad bank” of memories that will trigger the tears. While there are aids like glycerin and Visine. But nothing stands in for the real thing, says actor Bassam Kaado.

“The technique I use is honestly the same approach any actor should approach acting — being truthful in the moment,” Kaado tells Inverse. “If the circumstances and motivation are believable, I can be truthful and real in the moment.””

The moment can sometimes be elusive: Often, the most powerful moments we see on screen or on stage comes down to a combination of luck and craft.

“It’s surprising how easily you can find yourself crying or fighting back tears,” Edgar Lopez, an actor, tells Inverse.

Watching others cry, in turn, switches on our own emotions, whether that’s watching a friend go through a hard moment or watching a movie. Studies have found that watching a person elicits feelings of sympathy and compassion, as well as altruism. Vingerhoets and a team of other Tilburg University researchers explain in a 2016 paper in the journal Motivation and Emotion that seeing tears might connect us to the crying individual, and in anthropological literature, there are “several examples can be found of ritual or common weeping after adversity and disasters or when preparing for war, all suggesting that common tears forge bonds between people.”

And actually seeing tears might make a difference in how affected you are by another’s emotion. A 2009 study published in Evolutionary Psychology found that when they digitally removed the tears from a photograph of a crying individual, the facial expression became ambiguous to the viewer. Instead of the perception of sadness, study participants came up with varying answers to what the person in the photograph was feeling — ranging from fright to awe.

“When we see an individual crying, also in films, we consider him or her as more in need of help and we feel more connected to that individual,” Vingerhoets says. “Tears thus seem to facilitate our empathetic potential. Consequently, we are more willing to provide support. However, when we feel that crying is not appropriate or that it is not sincere and maybe even an attempt to manipulate, we may react with strong negative reactions.”

Which is why we likely feel very different when we watch Tommy Wiseau cry out “you’re tearing me apart, Lisa!” in The Room compared to say, the Little Ships of Dunkirk appear on the horizon in Christopher Nolan’s Oscar-nominated film. If you can empathize with the oscillating expressions of hopefulness and hopelessness, you can understand that joy and fear can grip you in the same way. And when that happens, you’ll probably be crying fat, rolling tears.