Readers reply: why do humans cry when they are sad?

I understand that tears flush away foreign objects from the eye. But what advantage does crying have when one is feeling sad (or happy)? Perhaps it is to signal an extreme of emotion, but then why would a solitary sad person cry when there was no one around? David Dobbs

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Readers reply

Does anyone remember crying as a kid and your parents told you: “I’ll give you something to cry about!” And you expected an almighty beating, but instead they just ruined the housing market? OhIAmSuchASadGit

Tears (especially “emotional” tears, rather than when you get something stuck in your eye) contain stress hormones such as cortisol, and so remove these hormones from the body. This helps you calm down. According to some researchers and scientists, crying is important for enhancing immune resilience. Laughing is too. Crying can trigger the release of opioids, which can influence the activity of immune cells, which may help our immune system become more effective. It could be regarded as an important mechanism that better protects our bodies when dealing with stressors, both internal and external. Lady_E

In terms of why we cry alone, I find sometimes people don’t know how to respond when others have cried in front of them, when they have been upset. It can be awkward, as many people can feel uncomfortable with the display of tears. I think when you are alone, you can release emotion freely through crying, you often feel better afterwards, and you don’t have to give a second thought to how others around you might respond. Amy

The human body is essentially a full functioning chemistry production facility. There are many triggers for a medley of different chemical responses. Many people are familiar with adrenaline activating during times of fear or excitement or dopamine triggering good feelings during times of accomplishment or relief.

Sadness has a chemical response as well, and it can be observed in the simple act of crying. There are differences between crying and lacrimation (that’s when you produce tears to clean or hydrate your eye), and those differences help us understand the purpose of tears.

So what exactly are those distinctions? The most relevant difference is that crying produces leucine enkephalin. There isn’t a simplified term for it, so let’s call it L.E. for now.

L.E. is an endogenous opioid peptide. If the word “opioid” stands out to you, then you probably see where this is going already; L.E. is comparable to morphine, and it produces a similar pleasurable effect.

This is why people feel better after a good cry. Next time you’re feeling sad and you know you’re only a few moments away from tears, let nature do its job. Crying is healthy, and it feels good. Phoenix Emberson, Texas

I can understand a baby crying for attention, but for the life of me I can’t fathom why (for example) I cry when a piece of music moves me. How on earth does that benefit me/increase my survival chances? This article suggests (among other competing theories) that crying is predominately a social signal that tells others you have a problem you cannot properly address. millie422

To be comforted and supported, perhaps. That gives an evolutionary advantage. Although we often cry alone, we often seek comfort from others, too. It’s a way of often inadvertently telegraphing we need consideration, whether or not we choose to share the reason for our upset. MaryVine

I would love to know the answer to this question, and more importantly how to turn it off. I find it very difficult to control tears, and was once told off by a hospital nurse for crying rather than “being strong” for my mother while my father was dying. I still cry a lot now, but wish I could turn it off, because it’s pointless. CantThinkStraight

What intrigues me about human crying is that as well as crying through obvious triggers like grief, stress, pain etc, we actively seek it out. Who hasn’t watched a film or read a book knowing it will make them cry at some point (for me, The Railway Children – film or book – gets me every time). It’s almost like we take a perverse pleasure in making ourselves feel sad just for the hell of it. Certainly if there are other animals who have the ability to cry, we’re the only ones who do it for the endorphin rush. Monstercat

It’s interesting that we cry for different emotions – pride, sorrow, sadness etc. This was well expressed by Mel Brooks on Desert Island Discs when he told Kirsty Young how Gene Wilder was unemployed and hard up when he auditioned for Blazing Saddles. “He wept when I told him he’d got the part. Then he wept a lot more when I told him how much I was paying.” beber_de_gorra

I used to cry in the mornings before I had to go to school, presumably to try to get a sympathetic response from my family. Then again, I was the headteacher so I never received it. yoshiboy

It’s really hard to suppress tears when you want to cry, so it is a pretty good indicator of genuine (as opposed to faked) emotion. A piece of evidence for this is that people cry when feeling powerful emotions even when alone, when there would be no point in fake-crying to deceive another. So it is tremendously useful for social bonding – someone who is crying has real feelings to which others can respond. In evolutionary terms this is very useful for group cohesion and trust. (It’s also hard to convincingly fake smiles or laugher, though pretty much everyone tries.) Mark_MK

Research suggests that when you cry, your body releases endorphins and oxytocin. These natural chemical messengers help relieve emotional distress along with physical pain. In other words, crying is a self-soothing behaviour. andya2015

Most answers seem to consider crying as an adult, and note the actually many contexts in which we may do so. Surely the point is it’s a hangover from being an infant attracting an adult? There are many contexts because infants simply cry when anything isn’t quite right – hungry, discomfort, feeling exposed to danger or indeed anything just outside their range of experience thus far.

Extremes of emotion (of any kind) as an adult I suspect simply inadvertently trigger the same deeply embedded infant response. What’s notable is that it’s at the extremes of emotion we’ve experienced thus far, hence as we get older, we often gradually shed tears less easily for the same thing – just like as an infant, in fact.

While howling makes sense as a signal, all the others – wavering voice, tears, shaking etc – seem more likely simply inadvertent side-effects of presumably the huge wash of hormones humans must need to sustain a long, loud howl that uses a huge amount of energy for an infant. The infant body is literally throwing the kitchen sink at what, for all it knows, might be a life or death situation.

This makes sense as the human body has a wide array of other unhelpful physical side effects to its own hormonal responses – tears etc are just unusually visible ones. (It certainly doesn’t make sense that tears are to vent cortisol, as an infant doesn’t want to calm down until an adult corrects the situation – it’s vitally important for its survival that it keeps it up indefinitely, if necessary, in fact.)

Over time, we’ve adapted these side-effects into social signals, an adaptation that prevented them from being selected away by evolution (not that there was much evolutionary pressure anyway, as long as the screaming worked) and indeed has refined them, so we can now express a few tears, say, without necessarily the whole howling rigmarole, but still elicit helpful – possibly life-extending – responses from the humans around us. HaveYouFedTheFish

Related: I thought crying wasn't for me – but now the floodgates have opened | Coco Khan

OK, but if we go with your explanation, why does the baby cry tears when needing to attract an adult? Yelling, screaming and sobbing would all do it, what does some liquid running out of the eyes add? Mark_MK

It’s even stranger than that, because babies don’t cry tears. They make all the noises associated with crying, but don’t add the actual tears until they’re several months old. SpoilheapSurfer

The most likely explanation for crying when in emotional or physical distress is that the brain is experiencing an overload in the production of endorphins. These are the natural opiate-like substances produced at various locations throughout the body, as well as in the brain, that mediate high levels of stress-based sensations. It is often said that the tears carry away excess levels of endorphins.

This may also explain why children cry in a “snuffly, snorty” fashion. It is thought that they may be sniffing back up the tears to maximise the calming effect of the endorphins. So contrary to Jacob Rees-Mogg’s nanny, one should never tell a child to stop crying and wipe away “those embarrassing tears”! They should be comforted and reassured and only the excess tears dabbed away. Martin Armstrong-Prior

I would like to understand why certain pieces of music – and it is only some – always set me off. There was a piece they always sang at my children’s end of term in primary school that I had to struggle to control myself through. I am sure I had never heard it before they started school, so it had no particular associations for me, yet there was no way I could sing it without crying. Ditto the hymn I Vow to Thee My Country, which again we never sang at my school – not sure when I first came across it, probably in a film. I have read all the comments so far and don’t feel we have really got close to understanding this fascinating question. Andreamaisie

I really hoped to read some good answers, but most comments seem to miss the point. It’s not: what advantage does expressing emotion have? It’s: why are various emotions – sadness, rage, happiness, frustration, love – expressed in this particular liquid way, when it’s so uncomfortable, blinding, and distracting? fredlil

People also cry in the presence of the profoundly awe-inspiring, sacred or spiritual. I once had a profoundly spiritual experience where I am convinced I experienced the presence of God and God’s love. I reacted as a blubbering mess and even 50 years later I’m unable to verbalise my experience without tears. Mantiki53