Appliance of Science: Why do we sometimes cry with laughter?

Laughing and crying are usually associated with two very different emotions and yet we have all cried with laughter at some stage or other, why is that?

Laughing is good for you both mentally and physically.

A few theories

When it comes to evaluating why we sometimes cry while we laugh, science is still playing catch up as, the truth is, no one is fully sure why we do it. That doesn’t mean there are not a few scientific theories though, and here are some of them.

A tight squeeze

Some scientists believe we cry after a bout of vigorous laughter simply because the physical movement of laughing can put a strain on our eyes. When we laugh a lot we can contract many of our facial muscles, including those around the eyes. It may simply be strong laughter can put too much pressure on our tear ducts, literally squeezing the tears out. There are many different types of tears, but, if this is the reason we sometimes cry with laughter, then these tears are what we call reflex tears.

Emotional centre

A strong laughter response is usually controlled by an area of the brain called the hypothalamus. Other emotions are controlled in this area too. It could be that the activity in the hypothalamus associated with strong laughter may also trigger other emotional responses at the same time, such as crying.

Stress relief

Laughing releases endorphins, those feel good hormones. Crying usually causes the release of endorphins too, which may help to ease physical or emotional pain. Both laughter and crying can alter the levels of other hormones within the body too, such as cortisol, a hormone associated with stress; so if laughing reduces stress, and crying reduces stress, maybe doing both at the same time has double the stress-busting power.

All the emotions

Crying and laughter are usually strong emotional responses to a variety of triggers and both can be hard to stop, once started. Some research teams investigating why we cry while laughing suggest that it is our body’s way of regulating itself in response to these strong emotions.

Social bonding

Although crying and laughing can be the result of two very different emotions, they are both ways of communicating, connecting and bonding with others. When we cry while laughing we may simply be reinforcing these social bonding in a particularly powerful way. If you think about it, it can be hard not to laugh along with someone who is laughing so hard that they cry; and once one person starts, others in the group tend to follow until the whole group is doing it. You may not remember what made you laugh so hard but you will likely remember where you were and the people you were with, and how good it felt.

Tears of joy

Of course, tears can be associated with other emotions and experiences too, not just sadness or extremes of laughter. We can cry when we achieve something big, when we feel love or affection intensely or we can even be moved to tears by a beautiful sight or act of kindness. Whatever the reason, it is clear that we do not just reserve the act of crying for expression of sadness, there is so much more to human tears, especially when combined with some side-splitting laughter.