Life got you down and the tears won't stop coming? Why do we cry, and what is the science behind it? Why are humans the only emotional crying animals? Does crying really make us feel better? And what evolutionary purpose does it serve? Well, turns out that you don't only cry when you're upset (or cutting onions). There are actually three types of tears: basal tears, reflex tears, and emotional tears. Basal tears perpetually lubricate your eyes, which serves the task of keeping them from drying out. Reflex tears are in response to an irritant like dust, (or that onion I mentioned) which release hormones in the brain to trigger a tear response in the lacrimal gland in your eyelids.
Emotional tears, be them tears of joy or tears of sadness (anger, frustration, fear...etc.), work more closely with the brain in the hypothalamus and basal ganglia. One theory suggests that emotional tears developed as a social signal, showing need, appeasement, or attachment and encouraging communication and empathy between people, ultimately increasing your chance of survival. Another theory states that emotional tears are a way to get rid of stress. This theory is backed by the fact that reflex and emotional tears have much different compositions, with emotional tears consisting of more proteins that are connected to stress. It is hypothesized that crying out these proteins could literally lower the amount of stress you're holding deep within!