Content area
Full text
C. de Weerth* and P. van Geert
There are indications that periods of disorganization/instability/regression accompany developmental transitions in early infancy. The goal of the present study was to validate a pattern of 10 strictly timed periods of emotional instability found through maternal reports by van de Rift-Plooij & Plooij (1992a), by means of ethological observations. A longitudinal study was carried out on four mother-infant pairs which were followed up weekly during a period of 15 months. The results failed to support the 10-period pattern. Possible explanations for these findings are presented, together with a discussion about methodological aspects of the data analysis.
In the search for developmental transitions, an important question concerns the criteria that distinguish normal variation or steady increase on the one hand, from transitions in the sense of discontinuities, on the other hand. In this Special Issue, methods and criteria derived from catastrophe theory have been applied in an attempt to unambiguously characterize those discontinuities.
In this study a different approach is followed. The criterion of instability is used to identify the occurrence of a number of transitions in infantile development. Instability can be roughly defined as a temporary loss of current behavioural competence, resulting in the upsurge of behavioural patterns characteristic of an earlier developmental level, i.e. regression. The starting point of our study lies in a claim by Van de Rijt-Plooij & Plooij (1992a) that there exist 10 periods of instability, which they called 'regressions'1, in the first 20 months of life. According to the authors, these regressions precede the onset of developmental transitions and are found in the emotional domain where they are characterized by temporary decreases, or even disappearances, of the growing independence of the baby, giving rise to instability in the sense defined above. In their longitudinal study, in which 15 mothers independently filled in a weekly questionnaire, an impressive consensus was found on the ages when their infants were reported to cry more and spend more time in body contact.
Strikingly, there were even weeks in which none of the mothers reported these behaviours, while during other weeks all of the mothers reported them. These regression periods took place around weeks 5, 8,12,17, 26, 36, 44, 52, 61-62 and 72-73, and were also often...