According to the UCL report, researchers found that contractions of the infant’s diaphragm muscle from a hiccup evoked a pronounced response in the brain’s cortex — two large brainwaves followed by a third. That postnatal processing of multisensory inputs, the researchers said, is important to develop brain connections.
"The activity resulting from a hiccup may be helping the baby's brain to learn how to monitor the breathing muscles so that eventually breathing can be voluntary controlled by moving the diaphragm up and down," said Lorenzo Fabrizi, the study's senior author.
“When we are born, the circuits which process body sensations are not fully developed, so the establishment of such networks is a crucial developmental milestone for newborns,” he continued.
That adults get the hiccups could just be a holdover from our infancy, Whitehead said.