My latest awkward attempt at science writing! Yay!

To wrap up my science writing adventure, Mike and I have agreed that I would take a single topic and address it for three separate audiences- children, adult non-scientists, and adults with relevant scientific background.  In order to sneak in one final chance at getting published, I used another “Ask a Scientist” question as my inspiration.

The question, asked by a 6^th grader named Mary, was “Why do kids react to getting hurt by crying? If something were to take the place of crying, what would it be?”

Here is the answer that I gave Mary, with some notes added:

“Crying, in some form or another, is something humans and many other animals do to signal to others when we are in pain and in need of help. Though opinions vary on whether or not humans are the only animals who actually shed tears in response to emotional or physical distress, it is clear that the behavior is significantly more evident in us than in any other species.  However, most mammalian and bird species do vocalize distress in a way that is recognizable by other members of their species (and, often enough, by us- maybe I can write about interspecies empathy next!).

Babies cry from the moment they are born for several very basic reasons- they are hungry, they are uncomfortable, they are tired, or they are in physical pain, though they do not actually produce tears until they are a few months old. Because they cannot communicate yet using language, their caretakers must be very well attuned the sound of their cries in order to interpret what they need. Though basal tears- which keep the eye moist- and reflexive tears- which are produced in response to irritation- develop within a few weeks after birth, babies do not have the capacity to cry emotional (or psychic) tears until they are about 7-8 months old.  The scientific literature on infant crying and its impact on caregiver behavior is vast, and a lot of really intriguing stuff has come out of it. Some studies have shown that hunger, pain, and general fussiness each produce specific crying patterns that can be identified.  Pain cries tend to have a higher pitch and intensity than other types of cries…and formal research aside, anyone I know who has spent significant time around infants and young children can rapidly recognize a wail of pain when they hear it. Interestingly, there is also some evidence that babies’ cries follow the cadence of the native language of their culture, which strengthens the idea that crying even in infancy has a distinctively social component.  A 2003 fMRI brain imaging study even showed differences in the brain’s response  to infant crying based on gender and parental status (Seifritz et al 2003).

           

As we grow older and develop language, we can ask for what we need more often than not and do not have to resort to crying.  However, sometimes when children are hurt they become overwhelmed and feel helpless, and crying is an easy and automatic way for them to express that and to get the attention, help, and comfort of their parents or someone else who is nearby. Adults typically have developed other ways of coping with physical pain and so are less likely to cry actual tears, but they may still yell or scream if something hurts badly. Of course, this isn’t 100% true.  Though I am not one to cry from physical pain- I am much more likely to say very bad words, very loudly- I know plenty of grown adults who cry when they are physically hurt. I’m not in a place to speculate as to what drives one reaction as opposed to another, but the fact is that, for whatever reason, the shedding of tears successfully fulfills its signaling function in adult humans. Research has shown that he likelihood that a person will respond to distress with tears is positively correlated with the probability of resulting social support- even elementary school aged children are able to apt to modulate their crying behavior in order to maximize positive responses and minimize negative or shaming ones.  

           

In addition to this, there are physiological reasons for crying as well. When something stressful happens, like an injury, our bodies produce chemicals that prepare us to react to a harmful event. Sometimes crying is a part of the activation of that system.  The exact role of crying (actual weeping, not simply tearing) within the stress response is not clearly defined, but studies suggest that it is linked to the parasympathetic response, which (very broadly) is the body's attempt to move back into "normal" mode following a stressful event. Evidence of this endocrine influence is in the tears themselves- emotional tears have traceable levels of a number of different hormones which are not found in basal or reflex tears. 

Interestingly, studies have shown that hearing a baby or child crying also activates the stress response system in the people who hear it, which is a good way to ensure that someone responds quickly to the person in distress.  So I think that if something were to “take the place” of crying, it would have to be something that could get the attention of someone to come and help.” This is just an interesting recap of what we’ve already covered- that crying as a social signal requires a sort of “give and take” between the distressed individual and another member of the social group. As it has been around a while in evolutionary time, this give and take, at least when it comes to the young, has in a way become hard-wired  

  I was pretty happy with what I managed to sneak into a 400 word response, but was also excited to have an excuse to dig a little deeper because, although this topic might seem like it came out of left field, the evolutionary and psychosocial significance of crying is actually the idea that first drew me an evolution-based view of behavior and health in the first place.

In 2004, though, when I attempted a literature review on the topic, I was able to find about a half dozen articles that dealt with crying as an adaptive behavior in neurologically intact adults. I ended up switching topics due to the lack of info…a last minute move which, because the universe has an interesting sense of humor, resulted in my turning in the paper three days late amidst lots and lots of tears.  I wish I could say that there’s been vast improvement to the literature and my time management skills, but I’d be lying on both counts.  Still, though- there’s something to be said for the eloquence of the situation.  My very last academic writing assignment is a mirror of my first attempt…and this time it was only one day late.

           

 Mampe, B., Friederici, A. D., Christophe, A., & Wermke, K. (2009). Newborns' cry melody is shaped by their native language. Current biology, 19(23), 1994-1997.

Seifritz, E., Esposito, F., Neuhoff, J. G., Lüthi, A., Mustovic, H., Dammann, G., ... & Di Salle, F. (2003). Differential sex-independent amygdala response to infant crying and laughing in parents versus nonparents. Biological psychiatry, 54(12), 1367-1375.