Contagious yawning as a cure for hiccups
Numerous treatments have been proposed for the relief of persistent or intractable hiccups, i.e., cases in which hiccups last for several days or up to two months or longer. Some of these treatments include medication, acupuncture, vagus nerve stimulation, and even rectal massages. Hiccups that fail to reach such extreme duration are far more common, yet remain irritating and famously lack a cure. Here, I propose (contagious) yawning as a candidate. In particular, I hypothesize that the extended stretching and lowering of the diaphragm during yawning, which cannot be replicated simply with deep breathing, could disrupt the spasmodic contractions of the diaphragm and inspiratory intercostal muscles that characterize hiccups. This hypothesis is consistent with the longstanding idea (traced back to the time of Plato) that bouts of sneezing can stop hiccups, since sneezing is thought to be a derived feature of yawning. Sneezes and yawns have similar motor patterns, including an initial long inspiration, tilting of the head, gaping of the jaw, and an exhalation. Unlike sneezing, however, yawning has the advantage of being reliably triggered through contagion by viewing, hearing, and/or thinking about yawns.