The Wonder Weeks: A Stress-Free Guide to Your Baby's Behavior is a book with advice to parents about child development by physical anthropologist Hetty van de Rijt and ethologist and developmental psychologistFrans Plooij. Their daughter Xaviera Plas-Plooij is a third author of recent editions. It was first published in English in 2003[1] as the translation of the 1992 Dutch book Oei, ik groei![2] The book claims that the cognitive development of babies occurs in predictably timed stages.[3] Ever since the systematic study of child development began at the beginning of the 20th century researchers have disagreed whether this is gradual or in punctuated stages.[4] Some figures in the child development field have objected that sleep regressions are not so predictable.[5] A chapter on sleep was added to the 6th edition in 2019.[6][3] The publisher has produced a mobile app based on the book.[7]
Claims
The book describes 10 predictable 'leaps' observed in a child's cognitive development during the first 20 months, with 8 in the first year. Months are counted from the due date because development begins with conception.[8] These developmental 'leaps' are said to begin with the baby becoming more insecure, clinging, and cranky, followed by a longer period in which the baby is more happy and learning new skills. They are predicted to occur at about 5, 8, 12, 17, 26, 36, 44, 53, 61-62 and 72-73 weeks old.[9]
Scientific Basis
Ethologists have documented predictable 'regression periods' in the interactions of mothers and infants in many species, suggesting an early origin in evolution.[10][11][12] In the course of a 1971-1973 longitudinal ethological study of chimpanzees in the wild, working with Jane Goodall,[13] van de Rijt and Plooij published additional data demonstrating predictable regression periods in Chimpanzee mother-infant dyads, the correlation of illnesses with these, and the importance of the mother's interactions for the baby's growing independence and learning.[14][15][16][17][18] They hypothesized a new type of learning important in the evolution of human parenting, with reference to an explanation in control theory.[19] To test this hypothesis, they applied the observational methodology of ethology to human mothers and infants. Their first human study, involving 15 Dutch mothers and their infants, with extrinsic sources of stress carefully controlled, was published in the Journal of Reproductive and Infant Psychology in 1992.[20][21]
Research into development of the central nervous system has identified periods of rapid change (PRC) which coincide with the observed regression periods,[22] and known stages of neurological development of the brain have been correlated with the behavioral observations.[23] Consistent with the hypothesis of increased stress, a correlation between regression periods and upticks of illness has been reported,[24] and a correlation with SIDS.[25] One peer-reviewed study included verification of parents' reports that babies master a cluster of new skills after each regression period.[26] Independent replication studies were carried out at universities in four countries, Groningen in the Netherlands,[27] Oxford in England,[28] Girona in Spain,[29][30] and Gothenburg in Sweden.[31] The failure of the first replication study was a subject of controversy.
Controversy
With state funding for an independent replication of the research with human mothers and infants, Frans Plooij obtained a temporary research position at the University of Groningen, where he had earned his degrees, and engaged a PhD student, Carolina de Weerth. She observed behavior of four infants and tested their cortisol levels as a measure of stress, and failed to find any evidence of greater fussiness or higher cortisol levels corresponding to the leaps.[27][32] She later suggested that this might be due to inadequate sample size.[5] Plooij objected that this was not a replication because the relevant data were obscured by extrinsic sources of stress which she failed to control,[33] and because the observational data were limited to her visits once a week, whereas in the original study the mothers recorded specified observations each half-hour interval of the day, and the researchers validated these data observationally with two of the 15 families.[34] De Weerth and her dissertation supervisor, Paul van Geert, said that Frans Plooij tried to pressure her into not publishing the study;[32] Plooij has disputed this account.[5] Plooij resigned his research affiliation with his alma mater.[32][35][36] De Weerth's dissertation was published with van Geert as the lead author.[27]
At a conference in 1997 (and published in 2003), Plooij and van de Rijt-Plooij reported that when the effects of those extrinsic sources of stress which de Weerth had identified are factored out from her data the regression periods are evident.[37] The following year, 1998, the scientific controversy was made the focal topic[38] of an issue of the journal Neuropsychiatrica with an article by Plooij,[34] a rejoinder by van Geert and de Weerth,[39] and a reply by Plooij.[40] Plooij has continued his research under other auspices.[41][42]
References
^Vanderijt, Hetty; Plooij, Frans X. (2003). The wonder weeks: how to turn your baby's 8 great fussy phases into magical leaps forward. Emmaus, Pa: Rodale. ISBN978-1-57954-645-8.
^Van De Rijt, Hetty; Plooij, Frans X. (1992). Oei, ik groei! [Ai, I'm growing!] (in Dutch). Ede and Antwerp: Zomer & Keuning Boeken BV.
^ abVerhoeven, Eymeke (2018-03-07). "Je kind loopt nog niet? Maakt niet uit" [Your child isn't walking yet? It doesn't matter]. Nederlands Dagblad (in Dutch). Retrieved 2024-02-25.
^Kalverboer, L. (1998). "Ontwikkelingssprongen in het duister: Over transities in de ontwikkeling" [Developmental leaps in the dark: On transitions in development]. Neuropraxis. 1. doi:10.1007/BF03070912. Verloopt het vroegkinderlijke ontwikkelingsproces geleidelijk of sprongsgewijs? Deze vraag houdt onderzoekers bezig sinds het begin van deze eeuw, toen de systematische studie van de ontwikkeling van het kind begon. [Is the early childhood development process gradual or in leaps? This question has preoccupied researchers since the beginning of this century, when the systematic study of child development began.]
^Hinde, R.A., ed. (1983). Primate Social Relationships: An Integrated Approach. Oxford: Blackwell Scientific.
^"Before our research, such regression phases had been found by others in 12 other primate species and two lower mammalian species, indicating that this appears to be an old phenomenon, perhaps emerging during the very evolution of life on earth" ("Introduction" (by F.X. Plooij), The Wonder Weeks p. 15).
^Plooij, F.X. (1984). Lipsitt, L.P. (ed.). "The Behavioral Development of Free-living Chimpanzee Babies and Infants". Monographs on Infancy. 3. New York: Ablex Publishing: 1–207.
^van de Rijt-Plooij, H.H.C.; Plooij, F. X. (1986). "The involvement of interactional processes and hierarchical systems control in the growing independence in chimpanzee infancy". In Wind, J. (ed.). Essays in human sociobiology, vol. 2. Brussels: VUB Press. pp. 155–165.
^van de Rijt-Plooij, H.H.C.; Plooij, F. X. (1987). "Growing independence, conflict and learning in mother-infant relations in free-ranging chimpanzees". Behaviour. 101 (1–3): 1–86. doi:10.1163/156853987X00378.
^van de Rijt-Plooij, H.H.C.; Plooij, F. X. (1988). "Mother-infant relations, conflict, stress and illness among free-ranging chimpanzees". Developmental Medicine & Child Neurology. 30 (3): 306–15. PMID3402672.
^Van de Rijt-Plooij, H.H.C.; Plooij, F. X. (1988). "Nonverbale interakties in de moeder-kind relatie bij vrijlevende chimpansees; Afstotingsprocessen: Conflict en leren, escalatie en ziekte" [Non-verbal interactions in the mother-infant relationship in free-living chimpanzees; Rejection processes: Conflict and learning, escalation and illness]. Nederlands Tijdschrift voor de Psychologie. 43: 105–114.
^Plooij, F. X.; van de Rijt-Plooij, H.H.C. (1989). "Evolution of human parenting: Canalization, new types of learning, and mother-infant conflict". European Journal of Psychology of Education. 4 (2): 177–192. doi:10.1007/BF03172599.
^Van De Rijt-Plooij, Hedwig H.C.; Plooij, Frans X. (July 1992). "Infantile regressions: Disorganization and the onset of transition periods". Journal of Reproductive and Infant Psychology. 10 (3): 129–149. doi:10.1080/02646839208403946. ISSN0264-6838.
^In the same year the first version of this book for the general public was published in the Dutch language. Van De Rijt, Hetty; Plooij, Frans X. (1992). Oei, ik groei! [Ai, I'm growing!] (in Dutch). Ede and Antwerp: Zomer & Keuning Boeken BV.
^Trevarthen, C.; Aitken, K. (2003). "Regulation of Brain Development and Age-Related Changes in Infants' Motives: The Developmental Function of Regressive Periods". In Heimann, Mikael (ed.). Regression periods in human infancy. Mahwah, NJ: Erlbaum. pp. 107–184. ISBN0-8058-4098-2.
^Plooij, F. X.; Rijt-Plooij, H. H. C. van de (1990). "Developmental transitions as successive reorganizations of a control hierarchy". American Behavioral Scientist. 34 (1): 67–80. doi:10.1177/0002764290034001007. S2CID144183592.
^Plooij, Frans X.; Rijt-Plooij, Hedwig H.C. van de; Stelt, Jeannette M. van der; Es, Bert van; Helmers, Roelof (2003). "Chapter 6: Illness Peaks During Infancy and Regression Periods". In Heimann, Mikael (ed.). Regression Periods in Human Infancy. Lawrence Erlbaum Associates. pp. 81–96.
^Plooij, Frans X.; Rijt-Plooij, Hedwig H.C. van de; Helmers, Roelof (2003). "Chapter 7: Multimodal Distribution of SIDS and Regression Periods". In Heimann, Mikael (ed.). Regression Periods in Human Infancy. Lawrence Erlbaum Associates. pp. 97–106.
^Sadurni, M.; Burriel, M. P.; Plooij, F. X. (2010). "The temporal relation between regression and transition periods in early infancy". The Spanish Journal of Psychology. 13 (1): 112–126.
^ abcde Weerth, C.; van Geert, P. (1998-03-01). "Emotional instability as an indicator of strictly timed infantile developmental transitions". British Journal of Developmental Psychology. 16 (1): 15–44. doi:10.1111/j.2044-835X.1998.tb00748.x. ISSN2044-835X.
^Sadurní, M.; Rostan, C. (2003). "Reflections on regression periods in the development of Catalan infants". In Heimann, Mikael (ed.). Regression periods in human infancy. Mahwah, NJ: Erlbaum. pp. 7–22. ISBN0-8058-4098-2.
^Lindahl, L.; Heimann, M.; Ullstadius, E. (2003). "Occurrence of regressive periods in the normal development of Swedish infants". In Heimann, M. (ed.). Regression periods in human infancy. Mahwah, NJ: Erlbaum. pp. 41–55. ISBN978-0805840988.
^Woolmore, Ashley; Richer, John (2003). "Chapter 3: Detecting Infant Regression Periods: Weak Signals in a Noisy Environment". In Heimann, Mikael (ed.). Regression periods in human infancy. Mahwah, NJ: Erlbaum. pp. 23–40. ISBN0-8058-4098-2.
^Plooij, F. X.; van de Rijt-Plooij, H.H.C. (2003). "Chapter 5: The Effects of Sources of "Noise" on Direct Observation Measures of Regression Periods: Case Studies of Four Infants' Adaptations to Parental Conditions". In Heimann, Mikael (ed.). Regression periods in human infancy. Mahwah, NJ: Erlbaum. pp. 57–80. ISBN0-8058-4098-2.
^Plooij, F. X. (2010). "The 4 WHY's of Age-Linked Regression Periods in Infancy". In Lester, B. M.; Sparrow, J. D. (eds.). Nurturing Children and Families: Building on the Legacy of T. Berry Brazelton. Malden, MA: Wiley-Blackwell. pp. 107–119.
^Plooij, F.X. (2020). "Chapter 8: The phylogeny, ontogeny, causation and function of regression periods explained by reorganizations of the hierarchy of perceptual control systems". In Mansell, Warren (ed.). The Interdisciplinary Handbook of Perceptual Control Theory: Living Control Systems IV. London: Academic Press. pp. 199–225. ISBN978-0-12-818948-1.