Daily length measurements (in centimeters) versus age (in years) for a male infant showing growth spurts.
Despite much anecdotal evidence and the convictions of many parents, biologists have not generally recognized the reality of short, sharp growth spurts on the order of 1 centimeter in a single 24hour period. Rather, the consensus has been that child growth was divided into three stages (infancy, childhood, adolescence), each characterized by different, but steady rates of growth. This conclusion was based upon annual and quarterly length measurements. However, when children are measured more often (weekly or daily), the growth curve is seen to be step-like rather than smooth, as in the accompanying illustration. Indeed, the mean amplitude of the growth spurts was found to be about 1 centimeter; and the duration of the spurts, about one day. These spurts punctuated long intervals of no growth. In infants, for example, 90-95% of their development is growth-free!
(Lampl, M., et al; "Saltation and Stasis: A Model of Human Growth," Science, 258:801, 1992.)
"Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada>, Vol. 81, no. 1 (1987), p. 24., 02/1987
