10: The Woman Who Died Laughing

In the chapter “The Woman Who Died Laughing,” two scenarios are brought up in which two individuals exhibit bizarre behaviors where they start laughing hysterically and then die (not instantly). One was at his mother’s funeral and couldn’t stop laughing, and within two days of being evaluated in a hospital, he died. Another case was Ruth Greenough, an 80 year old woman who experienced a headache and then erupted in laughter; this laughter eventually resulted in her death as well. After evaluations, both deaths were connected to abnormal activity or damage in portions of the limbic system.

The limbic system is the portion of the brain that deals with three key functions: emotions, memories and arousal (or stimulation). Structures include the hypothalamus, mammillary bodies and cingulate gyrus. A laughing circuit was suggested in which the structures of the limbic system interact to allow for this laughter. Although the mechanism is not evident, questions of the purpose of laughter begin to emerge.

Why do we laugh? Is there an evolutionary reasoning behind this action? Ramachandran introduced this topic by concluding that all structures are under the pressure of natural selection and thus evolve- the brain is no exception. His main argument was that laughter helps to explain why these circuits exist and that they emerged to alert or communicate with the rest of “their people.” Basically, if something seemed like a threat to someone, laughter assured the rest that there was nothing to worry about; laughter may have begun as a defense mechanism to pass off danger. Thus, unnecessary utility of energy and resources are avoided which is evolutionary favorable because individuals in the community are conserving their energy and resources for more important things such as avoiding predators and/ or taking care of their offspring. Laughter and humor are integrated in that laughter is the “physiological response to humor.”

Although humor is culturally based, laughter is the common denominator. Theories such as the “false alarm theory” and “nervous laughter theory” allow for examples that relate and further explain why this mechanism is evolutionary favorable and was selected for due to its advantageous outcome. An example of the false alarm theory would be hearing a sound that correlates with danger but ends up being associated with something innocent such as your pet or child. The humor comes from the contrast of what we initially think (an intruder/dangerous person) to it the actual source of the loud noise- your child getting paint on the floor or on their face (humorous). The relaxation that results from the laughter inhibits the biological fight-or-flight response. The nervous laughter theory is one that suggests that the initial emergence of laughter is now internalized to deal with truly stressful situations.

How does this tie to the limbic system and what does it have to do with the two individuals that “died from laughter?” Well, considering limbic system’s role in producing a response to potential danger, it would make sense that it could inhibit this response as well; the source of this inhibition being laughter. Although it’s not known what parts of the limbic system do what, it is clear that parts of this circuit handle emotions (the feeling from laughter) whereas other parts are involved in the physical act itself. Overall, the author firmly embraces that natural selection is the pressure/mechanism for evolution, but this evolutionary psychology is hard to prove right or wrong; thus each trait should be examined carefully and individually.