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Infant Development and Biological Rhythm at the Symposium of Infant Development in Shanghai

On October 13 (Fri) and October 14 (Sat), I had the opportunity to attend an international symposium on child-raising sponsored by the National Population and Family Planning Commission (NPFPC). I also visited a fair of children's goods at the exhibition hall in the Shanghai Trade Center Building next to the symposium's hotel venue. I was one of three speakers; a music education expert from the United States presented on music education for infants and a pediatrician from Germany lectured on the health system for mothers and children. In addition, there were also presentations by Chinese specialists in pediatric neurology, child development, demographic statistical analysis, etc.

A governmental organization, the NPFPC has long studied the effects of the "one-child policy" as part of its goal of ensuring the sound physical growth and emotional/psychological development of infants. Now that the "one-child policy" is practically the rule in urban areas of China, the government will now focus on implementing it in rural areas.

I was asked to deliver a lecture on "Biological Rhythm and Infant Development and Growth." Humans are born with a biological clock that was developed in the process of evolution. Synchronized with the rhythms of sunlight, it has given rise to the circadian rhythm that operates on an approximate 24-hour cycle and regulates our physiological functions. It is thought that the biological clock has already started to function at the fetal stage, but the circadian rhythm develops after birth in synchronization with sunlight. This synchronization process, however, requires some time. Infants sleep constantly at first. Nighttime sleep gradually lengthens and after the first year, their sleep rhythm approaches that of adults. It is not until four or five years of age that children stop napping in the afternoon and sleep only at night like adults.

Infants cry when they are hungry, their diaper is wet, or when they have a stomachache, but they will also wail loudly for no apparent reason. Anyone who has raised children has experienced this. In English, this type of crying is called "fussing cry, "inconsolable cry," or "colic." It tends to peak at five to six weeks and subside after no less than one year. Since this is a natural behavior, holding and gently stroking the infant are the only means of coping with it. Nevertheless, for mothers who are stressed and irritated by the demands of child-raising, it is not uncommon for this type of crying to lead to child abuse.

A pediatrician in Canada recently started educating mothers and caregivers about this natural behavior which he has named "PURPLE cry." Purple is an acronym for peak (crying peaks at five to six weeks after birth), unexpected, resistant to soothing, painful face (one of its characteristics), long-lasting, and evening (the time of day it tends to occur). It could also be called "nighttime crying."

Given the age at which it occurs, it is my opinion that purple crying results from the fact that sleep rhythm is not yet based on the circadian rhythm synchronized to sunlight. In other words, this is something similar to having jet-lag.

According to the research of Dr. T. Berry Brazelton of Harvard University in 1962, fussing cry peaks at five or six weeks after birth. In a recent letter to Professor Brazelton, who is an acquaintance of mine, I asked if fussing cry might not be explained by "jet-lag" due to exposure to sunlight rhythm when the fetus emerges as a newborn. While I did not receive a direct reply to my question, he did note that a comparative study of infants born in October and April in Iceland showed that October-born infants are calmer than those born in April. Perhaps this is because it is darker and less necessary to adjust one's clock to outside light. I am interested in learning more about this from researchers in this field.

Of course, the circadian rhythm that puts them to sleep is not the only rhythm that infants need in order to live. Other rhythms are pulse and respiration, for example. There is also a rhythm to communication, as is clear from the nodding that occurs in conversation between adults.

I would like to point out here that rhythm is also a feature of communication between infant and mother (caregiver). The infant moves his or her hands, feet and body in time to the rhythm of the mother's voice as she talks, just as we adults nod to the rhythm of the other party in a conversation. This phenomenon is called "entrainment." Through this process, the mother and child come to share a common space, bond emotionally, and the infant develops language by absorbing (committing to memory) each of the mother's words in their shared information. In this sense, the physiological rhythms can be said to affect all aspects of the infant's life.

The Chinese participants and audience responded favorably and with interest to my presentation. As a result of my experiences during this trip, I very much like to deepen communication and exchange with China through Kodomogaku (Child Science).
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