allow the crying to run its course. Other studies have supported Kitzinger's findings. Babies who had experienced birth complications had longer crying spells at three months of age and awakened more frequently at night crying.

Based on these various findings, Aletha Solter has proposed a general emotional release theory of infant crying. When infants cry for no obvious reason after all other causes (such as hunger or pain) are ruled out, she suggests that the crying may signify a beneficial stress-release