I'm a crier. I'm not ashamed. I'm a man who cries. Not in real life of course, but when watching movies. I've not quite worked out what the triggers are, but they often involve the relationships between parents and children.

Consider the movie Field of Dreams, which is, on paper, a bizarre tale in which Kevin Costner builds a baseball pitch in the middle of his corn crop because he heard a voice. Costner thinks he's bringing back the shamed player Shoeless Joe Jackson from the grave, but actually he ends up meeting (spoiler alert!) his father as a young man. In those final scenes, I'm in pieces.

Field of Dreams is deliberately emotionally manipulative. How about this: I also cried in The Force Awakens. I sat with my daughter, clutching each other's hands, and we were both in tears. She's 10. She's also female. According to society's rules, I supposedly have no such excuse.

If men do cry less, why is that? And what are the benefits of shedding tears?

Is it unusual that I regularly cry as a man? It's just one of the questions I've been looking into recently for the BBC Radio 4 series The Curious Cases of Rutherford and Fry. My co-presenter Hannah and I have been exploring the science of crying: if men do cry less, why is that? What are the benefits of shedding tears? And evolutionarily-speaking, why do we even cry at all?

The answer to the question of whether I am unusual is straightforward. According to pretty much every study done, women do cry more than men, and this result has been consistent since we've been looking. Psychologist William Frey's study in 1982 calculated that women cry on average 5.3 times a month, whereas men in all their manliness only allow eye leakage 1.3 times a month. On average when a woman cries it's likely to be for five or six minutes, compared with two or three minutes for a manly weep.

Dutch psychologist Ad Vingerhoets from Tilberg University is the man when it comes to weeping. He's one of only a few researchers who pursue tears, and his results have all confirmed that there's a gender dichotomy, and that it starts in childhood. In infancy crying is gender neutral and universal: all babies do it equally. (Evolutionary psychologists argue that crying in babies exists as an acoustic indicator of parental need. I think parents might have already figured that one out.)

So what explains the gender differences that emerge as children age into adults? It's clear that cultural factors play a significant role. Indeed, indirect findings support that notion: studies repeated in different countries revealed that people cry more in countries where crying is more socially acceptable. Vingerhoets also found that more weeping occurs in affluent countries, the implication being that prosperity somehow frees us to be more emotionally expressive, and turns people into cry-babies.

But he thinks that it's not only social conditioning that restricts men's crying, but testosterone too. He's reported that prostrate cancer patients being treated with drugs that lower testosterone levels cry more – though you might argue that they're a bit more emotionally fragile because they've got cancer.

Back to the movies, there is a terrible line from Terminator 2 – an otherwise great film – where Arnold Schwarzenegger's titular cyborg from the future observes the child under his protection having a minor weep after a tough day (everyone he knows has been murdered), and asks in his robotic Teutonic tones this simple question: 'why do you cry?'

Here's the answer (spoiler alert!): we don't know.

Humans are the only species that cry for emotional reasons (there was some suggestion in the past that elephants might cry in mourning, but it hasn't stood up to scrutiny). It's an oddly under-researched topic. We don't know why we cry in physical pain. We don't know why we cry from emotional trauma (so-called psychic tears), or even in moments of great happiness. As we are such social beasts, it might be an indicator, an external way of conveying profound and important internal mental state. But this is all guesswork.

Humans are the only species that cry for emotional reasons

Maybe it's catharsis. Another one of Vingerhoet's recent studies attempted to assess the adage that people feel better after a good cry. In 2015 he asked volunteers to report their emotional state before watching one of two known tearjerker movies. One was Life is Beautiful, the Oscar-winning, heart-stirring tale of a Jewish man coping with the Holocaust through comedy and pathos. The other was Hachi: A Dog's Tale. They were then asked to fill in the same form immediately after watching, 20 minutes after and two hours after. The results were pretty clear: those who didn't cry reported no change in temperament. For those who cried, their mood significantly improved afterwards, which could be interpreted as having a cathartic effect. People seemed to feel better after a good cry.

On The Curious Cases of Rutherford and Fry radio programme, we like to do small experiments and replicate studies to answer the questions the listeners send in, and we decided to replicate the film study. The Fry half of our duo seems to relish subjecting me to less than joyous experiences in the name of science. At Hannah's cackling behest, I have endured traffic on the M25, I have been forced to faint, and most recently had my back waxed. However none of these compared to the sheer awfulness of watching Hachi: A Dog's Tale – to try and make me cry.

Here is my review: Hachi is a dog who is adopted by Richard Gere. (Spoiler alert!), Richard Gere dies. Hachi is sad. The end. One can only assume that Richard Gere had begged the screenwriters for an early release from this stinker. I didn't cry at Hachi, and (spoiler alert!) I certainly didn't feel any better, which is in line with Vingerhoet's results. Maybe I should've let the floodgates open.

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