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 6th 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.
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