This dissertation studies two consecutive cohorts of kindergarten pupils in a large-scale experimental digital reading (and math) intervention," What Works for Whom ". It looks into the... Show moreThis dissertation studies two consecutive cohorts of kindergarten pupils in a large-scale experimental digital reading (and math) intervention," What Works for Whom ". It looks into the differential effects of digital interventions for children experiencing mild perinatal adversities. Additionally, it examines how to deal with missing data using a planned missing data approach, and studies mechanisms (both internal and external to the pupils) that may account for differential intervention effects. Show less
A remarkable finding in recent research in psychopathology is that not every child is equally susceptible to interventions. Research showed that genetic differences, and in particular a... Show moreA remarkable finding in recent research in psychopathology is that not every child is equally susceptible to interventions. Research showed that genetic differences, and in particular a dopamine-related gene, DRD4, predict who will benefit from interventions, and who will not. In the project "What Works for Whom", this theory was tested, on a large-scale, in the field of early literacy. More than 180 schools spread over the Netherlands were involved in the experiments. We tested the hypothesis that children who were carrier of the DRD4 7-repeat allele, were more receptive to digital educational interventions; one program aimed at understanding the alphabetic principle, and the other program included digital storybooks with animated illustrations. Results for the book reading program were in line with the differential susceptibility theory. The carriers of the DRD4 7-repeat allele, about one-third of the children, benefitted extra from digital storybooks and outperformed their non-carrier peers. For non-carriers the digital books added nothing to the experience children already had with book reading in school and at home. For carriers of the DRD4 7-repeat allele the digital storybooks are a new essential in the curriculum in kindergarten. Show less
Parenting influences many aspects of child development, including socio-emotional, cognitive, and behavioral outcomes. Yet most studies report only modest effect sizes. An increasingly likely... Show moreParenting influences many aspects of child development, including socio-emotional, cognitive, and behavioral outcomes. Yet most studies report only modest effect sizes. An increasingly likely explanation is that not all children are equally affected by environmental factors, including parenting. The differential susceptibility theory proposes that some children might be more susceptible to both positive and negative environmental influences, compared to other children. Such differences in susceptibility are thought to be due to genetic, temperamental, or physiological susceptibility factors. In the current thesis, we tested the theory of differential susceptibility of children to the effects of parenting in a large population-based cohort, the Generation R Study. Doing so, we went beyond common methods. First, we investigated differential susceptibility from a developmental perspective by including multiple measures over time. Second, we went beyond single-gene/polymorphisms in the investigation of gene-environment interplay by aggregating genetic variation in a set of dopamine genes. Third, we extended previous research on mild perinatal adversity as a susceptibility factor by examining its moderating role in the association between harsh parenting and hair cortisol levels, taking into account background factors that we demonstrated to be of influence on hair cortisol levels. Show less
BookStart has been developed to enhance parent-child verbal interactions in early childhood by promoting book sharing. Parents receive a voucher for a baby book and free access to baby books in... Show moreBookStart has been developed to enhance parent-child verbal interactions in early childhood by promoting book sharing. Parents receive a voucher for a baby book and free access to baby books in the library. In a large-scale research, we found that if parents complied with the BookStart suggestion to start in the first year with book sharing, their children’s language scores in the second year were higher than those of a similar group of children not exposed to BookStart. In addition we found that book reading was a better predictor of language skills at 22 months than at 15 months, which may indicate a snowball effect. A reactive temperament proved a risk factor for language development, due to low verbal stimulation from parents in the first years, but an asset when parents increased verbal parent–child interaction under influence of BookStart. Lastly, we found that parents from children with a difficult temperament participated more frequently in BookStart, possibly because they felt that the quality of verbal interaction in their family needed improvement. Parents with a low educational background appeared to be less attracted to BookStart, probably because they do not realize the importance of early book sharing for child language development. Show less
The development of self-regulation is one of the major challenges of a child’s healthy development. In the current thesis, the contribution and interplay of parental and biological factors in... Show moreThe development of self-regulation is one of the major challenges of a child’s healthy development. In the current thesis, the contribution and interplay of parental and biological factors in the development of self-regulation in preschoolers are studied in a large population-based cohort, the Generation R Study. We found that attachment insecurity in infancy was related to higher levels of toddler active resistance during Clean-Up. Maternal negative discipline was related to lower levels of committed compliance in toddlers, and the association between maternal positive discipline and child committed compliance was moderated by the child’s COMT rs4680 genotype, indicating that the association was stronger in children with the Met/Met variant than for children with other COMT genotypes. Maternal family-related stress during pregnancy predicted lower levels of toddler committed compliance through lower levels of maternal positive discipline. Maternal sensitivity was associated with lower levels of executive function problems and lower levels of internalizing problems in preschool age. In children with a relatively short corpus callosum in infancy, higher levels of maternal positive discipline predicted lower levels of inhibition problems. Our studies demonstrate the role of various aspects of positive parenting and mother-child relationship quality in preschool children’s regulation of emotions and behavior. Show less
Early interventions address concerns that an unacceptably large number of children are already, by four years of age, lacking in competencies fundamental to success in learning to read. Using a... Show moreEarly interventions address concerns that an unacceptably large number of children are already, by four years of age, lacking in competencies fundamental to success in learning to read. Using a randomized controlled trial, the studies presented in this thesis examined program features and children__s behavioral and genetic characteristics (e.g., regulatory skills and DRD4) that might be of influence on learning effects of an exemplary computer intervention program Living Letters. Our conclusions include three major points. First, computer-aided instruction can be a useful tool in early literacy education, even in kindergarten-age (chapter 2). Second, the efficiency depends on the presence of immediate and individualized oral feedback. Without feedback the target program is not a stronger stimulus for learning code-related skills than daily experiences with written language (chapter 3). Third, a large part of the children benefits from the computer intervention but not all children. Susceptible children outperform the rest with a program enriched with positive, responsive interactions; they suffer more from instruction without these vital elements. The less susceptible group benefits from all opportunities for learning without excelling in the most helpful condition (chapter 4). This susceptibility is associated with a genetic predisposition to dopamine-regulated reward- and attention-related mechanisms and may influence learning via executive attention (chapter 5). Show less
Letters in Beweging is een interventieprogramma voor kleuters met een achterstand in alfabetische kennis. Op 15 scholen is dit programma uitgetest onder vijfjarigen (n = 135) met de laagste scores ... Show moreLetters in Beweging is een interventieprogramma voor kleuters met een achterstand in alfabetische kennis. Op 15 scholen is dit programma uitgetest onder vijfjarigen (n = 135) met de laagste scores (30% laagst) op alfabetische kennis. Het programma waarmee een deel 15 weken lang telkens een kwartier zelfstandig oefende, liet niet alleen direct na afloop van het programma effecten zien. Gedurende de volgende twee leerjaren bleven effecten zichtbaar in de leesprestaties. De groep die het programma kreeg, was in groep 3 en 4 niet meer te onderscheiden van de klasgenoten (n = 269) die als kleuter geen achterstand hadden in alfabetische kennis. De controle groep raakte in groep 3 en 4 steeds verder achter. Het meest verrassende resultaat is dat een risicogroep met lichte perinatale afwijkingen in het bijzonder profiteerde van de interventie. Vanaf 2000 worden zwangerschap- en geboortegegevens van alle Nederlandse kinderen in het perinatale register opgeslagen dat met toestemming van de moeder toegankelijk is voor onderzoekers. In de groep met lichte perinatale problemen (ruim 20%) scoorde de interventiegroep meer dan een standaarddeviatie hoger dan de controlegroep zowel direct na de interventie als een jaar later. In de groep zonder perinatale problemen werden geen effecten van het programma aangetoond. Dit resultaat is niet alleen een verdere onderbouwing van de theorie van differenti_le gevoeligheid, i.e., sommige kinderen zijn gevoeliger voor zowel een positieve als negatieve omgeving, maar impliceert ook uitbreiding van de theorie naar het cognitieve domein. Show less
The thesis ‘Quality in home-based childcare: Impact and improvement’ consists of two studies. The general aim of the first study is to examine children’s stress levels and wellbeing, and the role... Show moreThe thesis ‘Quality in home-based childcare: Impact and improvement’ consists of two studies. The general aim of the first study is to examine children’s stress levels and wellbeing, and the role of caregiver stress and childcare quality. This first study is described in chapters 2, 3, and 4. Chapter 2 addresses the question whether children’s cortisol levels (and wellbeing) differ between contexts (childcare day or at home day) and setting (childcare homes and childcare centers), and associations with childcare quality are examined. Chapter 3 reports on caregivers’ cortisol levels (and perceived stress) between contexts (work day, non-work day) and setting (childcare homes and childcare centers). In addition, associations between caregiver stress and childcare quality are examined. Chapter 4 investigates associations between caregivers’ cortisol levels (and perceived stress) and children’s wellbeing and cortisol in home-based childcare. Also, children’s temperament is taken into account. In the second study, described in chapter 5, we test the effectiveness of the Video-feedback Intervention to promote Positive Parenting – Childcare (VIPP-CC) in enhancing childcare quality in home-based childcare. Show less
This thesis addressed the physiological impact of fear in 4- and 7-year-old children, induced by media and social fear-inducing tasks (the Trier Social Stress Test for Children). The main question... Show moreThis thesis addressed the physiological impact of fear in 4- and 7-year-old children, induced by media and social fear-inducing tasks (the Trier Social Stress Test for Children). The main question pertained to individual differences in physiological reactivity to fear-inducing stimuli. The possibly relevant factors of attachment security, the child’s temperamental fearfulness, and variations in the serotonin transporter gene (5-HTTLPR; long vs. short allele) were taken into account. Results showed that temperament, attachment, and genetic influences play significant and interactive roles in the expression of fear reactivity. A secure relationship affected the reactivity to media-induced fear stimuli in temperamentally more fearful children but not in less fearful children irrespective of children’s ages. This finding adds to the growing literature showing that children high in negative emotion are more susceptible to positive as well as negative rearing influences. Furthermore, we found evidence that reactivity to the social fear-inducing task was explained by a combination of variations in the serotonin transporter gene and attachment security. Children with a secure attachment representation and two long 5-HTT alleles showed the lowest levels of fear reactivity, indicating that physiological reactivity to a social fear-inducing task is a product of the child’s biology and environment. Show less
The general objective of this thesis was to test the effectiveness of an early intervention program aimed at reducing externalizing problems in 1- to 3-year-old children by enhancing parental... Show moreThe general objective of this thesis was to test the effectiveness of an early intervention program aimed at reducing externalizing problems in 1- to 3-year-old children by enhancing parental sensitivity and adequate discipline strategies. A new intervention was designed for this study: the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) The study consisted of a screening phase in a general population sample (N = 2408) and a randomized case-control intervention phase in a selected subsample of children with high levels of externalizing behavior problems (n = 237). The results of this thesis show that externalizing problems occur in children as young as 1 year of age and are moderately predictive of externalizing problems one year later. Furthermore, child temperament appears to be a moderator in the association between maternal discipline strategies and externalizing problems. Children with difficult temperaments are more susceptible to both negative discipline (i.e., showing more externalizing problems) and positive discipline (i.e., showing less externalizing problems) compared to children with relatively easy temperaments. Finally, the VIPP-SD intervention was effective in improving maternal attitudes towards sensitivity and sensitive discipline, enhancing actual maternal sensitive discipline practices, and decreasing the children's level of overactive behaviors. Show less
