Why do we cry?

I was recently reading an article on the psychology of why we cry (via):

In a study published in 2000, Vingerhoets and a team of researchers found that adults, unlike children, rarely cry in public. They wait until they’re in the privacy of their homes—when they are alone or, at most, in the company of one other adult. On the face of it, the “crying-as-communication” hypothesis does not fully hold up, and it certainly doesn’t explain why we cry when we’re alone, or in an airplane surrounded by strangers we have no connection to…

In the same 2000 study, Vingerhoet’s team also discovered that, in adults, crying is most likely to follow a few specific antecedents. When asked to choose from a wide range of reasons for recent spells of crying, participants in the study chose “separation” or “rejection” far more often than other options, which included things like “pain and injury” and “criticism.” Also of note is that, of those who answered “rejection,” the most common subcategory selected was “loneliness.”…

Although biological reasons have been proposed, they often seem a bit silly to me. So I tried to dig into the neurobiology literature – and found just about nothing. It’s actually kind of hard; there’s basically nothing, so far as I can tell. What do we know about the neurobiology behind this intensely social behavior?

There are clues from a paper in 2001 crying is somehow related to laughter. Some people suffer from a neurological disorder known as pathological laughter and crying which is exactly what it sounds like: crying at a moderately sad movie or laughing uncontrollably when frustrated. Here is a video of someone with pathological laughter, and here is another video explaining it (and the connection with MS). This is not so surprising when you think about it. After all, who doesn’t know someone who has cried from happiness or laughed at something sad?

These two things may be linked because they are part of a proposed ‘laughing and crying center’ of the brain, located in the brainstem. In fact, anyone who suddenly begins pathologically laughing should be careful as it is a warning sign of a brainstem stroke. This emotional center probably receives input from the cerebellum; a patient who had a lesion in the cerebellar peduncle, which sends information from the cerebellum to the brainstem, was a pathological laugher and cryer. The authors suggest that the cerebellum usually integrates all sorts of social cues to guide behavior but when it cannot do it’s job properly laughing and crying occur inappropriately.

The cerebellum is an accordion-like structure that often gets accused of being a primitive lizard brain. Whenever a structure looks old, people assume it’s archaic and can’t have evolved to do anything new. But the cerebellum has more than three times as many neurons as the whole neocortex, and is responsible for a lot that it doesn’t get credit for. Other portions of the brain that are involved in emotion and social behaviors, such as the serotonin-producing raphe nuclei and the hypothalamus, send information to the cerebellum and damage to the cerebellum is linked to disinhibited and inappropriate social behavior, as well as a generally lower intellect.

The moral of the story is that crying is a response to all kinds of social cues which psychologists are equipped to study while neuroscientists are unable to. About all we can say is that a structure that coordinates social input is playing an intricate role in controlling tears.

Update: I have a new blog post with a little more information. Apparently, stimulating the orbitofrontal cortex – a region connecting to the ’emotion center’ of the amygdala, while also dealing with (positive and negative) reward – is able to cause crying and feelings of sadness.

Reference

Parvizi J, Anderson SW, Martin CO, Damasio H, & Damasio AR (2001). Pathological laughter and crying: a link to the cerebellum. Brain : a journal of neurology, 124 (Pt 9), 1708-19 PMID: 11522574

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13 thoughts on “Why do we cry?

  1. There were two things mentioned in this article that can be linked to why we cry and the reason why we do it. The cerebellum is in charge of the body’s control of balance, muscle tone and coordinated muscle movements and it is also in charge of our automatic movements and motor skills. When something occurs and a person starts crying, it is almost involuntary, or automatic because the brain gets those messages that tells the person to cry and the cerebellum does its job. Serotonin is whatever has to do with the person’s sleep, moods, emotional states, and sensory perception. It would make sense that this neurotransmitter would have a part in making a person cry due to the fact that its job is to make the person feel things emotionally and effect their mood and makes the person cry according to the mood. With multiple things working in the brain and messages being sent throughout the body, it is likely that other things in the brain make a person cry as well like the amygdala, which is in charge of the person’s fear and anger and also emotion and memory. This can be a factor to crying because when a person is afraid or when a person is angry or frustrated, they are likely to cry.

    • Right. There’s other areas that have been implicated as well, like prefrontal cortex. From my (brief) reading of the literature, though, no one knows what’s going on – this paper is from over a decade ago and afaik is the last word (!) on this.

      I would also be unsurprised if serotonin/amygdala were highly involved, but I didn’t see any direct evidence for it. I wouldn’t be surprised if other hormones/modulators were involved, too.

      I was kind of hoping some sort of “crying specialist” would pop on here to tell me what’s what 😉

  2. This article was very interesting. The Amygdala and Hypothalamus play a key role with emotions. The amygdala is located at the base of the temporal lobe and has many emotional responses, like fear and anger. It is also appeals to upsetting emotional stimuli which can trigger someone to cry. The hypothalamus is also very Important. It is also referred to as “the brain within the brain.” It controls many different things along with behaviors that are related to survival. If they are in a survival mode they can be panicked and scared, which could cause them to cry. When the brain receives an upsetting emotion it can stimulate the person to cry because of many functions in the brain.

  3. I found this article very interesting. I was able to relate things within it to the current topic I am learning. I also found myself highly interested and amused reading about the pathological laughter and crying. My thoughts regarding the main idea, “Why Do We Cry?” are similar to that of the above commenter. The first thing that came to my mind while reading the article was the amygdala along with the hypothalamus and, somewhat, the frontal lobe. The amygdala, I feel, plays a large role in this subject due to its connection with emotional responses in the brain. I noticed no one has mentioned the frontal lobe, but I feel it also could lead to the emotional responses of crying, laughing, ect. I believe this to be true because from what I have read, the frontal lobe is not only involved in thinking and planning, but also emotional control.

  4. Why do we cry? It really is a good question. No doubt the emotional centers of the brain play a role in this, such as the hypothalamus and the amygdala, as everyone seems to agree. But is this an strictly an emotional response? And how is this response triggered? I would bet the triggering of this response lies somewhere in the process of neurotransmitters, most likely serotonin, being released in the brain. Now rather the response is triggered through a hormonal process or if it comes from the nervous system i have no way of saying. But in agreement with everyone else on this subject, its a safe bet that this response is brought about somewhere in between the release of theses neurotransmitters and the parts of the brain receiving the stimuli that activate it.

  5. Why do we cry? Crying is an involuntary response that can be due to a positive or negative experience we go through. Crying is triggered from neuron cell bodies found at the base of the temporal lobe of the brain, known as the amygdala. The amygdala plays a major role in the crying factor because it’s involved in a variety of emotional responses that include anger, fear, or disgust. Serotonin is also involved in emotional states, sensory perceptions, sleep, and moods. This neurotransmitter sends messages to the cerebellum which is the reason we will get emotional whether it be due to a funny movie, feelings of fear kick in, or death in the family.

    • In fact crying originate in the brainstem, which is one of the most basic regions of the human brain, yet it is one of the most vital regions for our body’s survival.

  6. Pingback: Why do we cry? (Part 2) | neuroecology

  7. I’ve wondered about the “Triune brain” concept for some time — it’s entered the popular discourse (TED talks) to a degree that I have to feel sceptical about it. And it sounds like you’re maybe talking out against it here:

    Whenever a structure looks old, people assume it’s archaic and can’t have evolved to do anything new.

    Have you written about the triune concept elsewhere?

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