Wat bepaalt de kwaliteit van gehechtheid? In een grootschalig onderzoek, Generation R, zijn de stresshuishouding en enkele kandidaatgenen van de kinderen onderzocht, en het gedrag van de ouder. De... Show moreWat bepaalt de kwaliteit van gehechtheid? In een grootschalig onderzoek, Generation R, zijn de stresshuishouding en enkele kandidaatgenen van de kinderen onderzocht, en het gedrag van de ouder. De gehechtheidsrelatie is de relatie tussen een kind en een ouder (of andere stabiele verzorger) die in het eerste levensjaar wordt opgebouwd. Veilig gehechte kinderen gebruiken hun ouder als veilige haven van waar ze de omgeving verkennen. Onveilig gehechte kinderen hebben hier moeite mee; zij kunnen niet de juiste balans vinden tussen contact met de ouder en het verkennen van de omgeving. Dit onderzoek laat zien dat onveilig gehechte kinderen heftiger op stress reageren dan veilig gehechte kinderen. Wanneer er sprake was van depressie in het leven van de moeder, leidt dit tot een verdere toename van stress bij de onveilig gehechte kinderen. Hetzelfde gold voor onveilig gehechte kinderen met een risico-gen dat verantwoordelijk is voor een minder goede stressregulatie. Verder vonden we dat sensitief opvoedgedrag van moeder leidde tot meer veilige gehechtheid, maar alleen wanneer het kind een bepaalde variant van een gen droeg dat van belang is bij het omgaan met stress. De resultaten laten de kwetsbaarheid en stressgevoeligheid van onveilig gehechte kinderen zien. Daarnaast kunnen we op basis van de huidige resultaten zeggen dat insensitief opvoedgedrag, depressie van moeder en genetische risico’s een rol spelen bij onveilige gehechtheid. De ontwikkeling van gehechtheid is complex, en het resultaat van het samenspel tussen biologische aspecten en de opvoedingsomgeving. Daarop moet toekomstig onderzoek dan ook gericht zijn. Show less
There is a widely held belief that reading (story)books makes us smarter and helps promote success in life. Does scientific evidence support this notion? The three meta-analyses in this thesis... Show moreThere is a widely held belief that reading (story)books makes us smarter and helps promote success in life. Does scientific evidence support this notion? The three meta-analyses in this thesis comprise 146 studies between 1988 and 2010 (N=10,308 participants) that addressed the role of book reading in language and reading development from infancy to early adulthood. Chapter 2 shows that reading routines that are part of children’s and students’ leisure-time activities offer substantial advantages for the development of language, reading, and spelling proficiency and academic success. The finding that leisure-time reading becomes increasingly more important across education seems natural: Because more skilled readers are more likely to enjoy books, they will choose to read more frequently which, in turn, will improve knowledge of word forms and semantics and enhance vocabulary size and text comprehension abilities. It appears from intervention studies comprising 2-6 year old children that it makes sense to invest in improvement of the quality of adult-child book sharing. Training parents or preschool and kindergarten teachers intensively in interactive reading techniques (e.g., dialogic reading programs) appears to be a promising venue to expand pre-conventional readers’ oral language (see chapters 3 and 4) as well as knowledge about the basics of reading (see chapter 4). Show less
Child maltreatment is a global phenomenon affecting a significant number of the world’s children. The purpose of this study was to compare the prevalence of self-reported childhood maltreatment... Show moreChild maltreatment is a global phenomenon affecting a significant number of the world’s children. The purpose of this study was to compare the prevalence of self-reported childhood maltreatment among university students in Kenya, Zambia, and The Netherlands. We also sought to compare the psychopathological sequelae of child maltreatment in the three samples. In addition, we sought to find out whether PTSS mediated the association between child maltreatment and the psychopathological symptoms. The results of our study showed that neglect in childhood was the most prevalent of all forms of child maltreatment across the three samples. Physical abuse and sexual abuse was most prevalent in Kenya and Zambia while witnessing interparental violence was the least prevalent in the two samples. Child maltreatment was differentially associated with psychopathological symptoms in the three samples of our study. Notably, neglect was the most predictive of psychopathology symptoms. The cross-validation results of our study showed that there were no significant differences in the predictive patterns of PTSS from child maltreatment in the three samples. PTSS mediated the association between child maltreatment and psychopathology symptoms albeit differentially. The results of our study show that there is need to mitigate the prevalence and sequelae of child maltreatment. Show less
The present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are... Show moreThe present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are used to heighten cortisol levels, and consequently to study its effects on working memory performance and memory retrieval. In addition, by using neutral and emotional distraction during working memory, effects of cortisol on emotional distraction were investigated, also with use of functional imaging. Overall, it was consistently found that high cortisol levels, by hydrocortisone administration or induced by stress, reduced the distraction by emotional irrelevant stimuli, hence improving working memory. The current findings might be relevant for patients suffering from posttraumatic stress disorder, who typically suffer from trauma-related intrusions. 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 examined the development of adopted children to shed more light on the effects of deprivation on child development and the potential for catch-up and recovery after placement in the... Show moreThis thesis examined the development of adopted children to shed more light on the effects of deprivation on child development and the potential for catch-up and recovery after placement in the more advantageous environment of an adoptive family. In the first part of the thesis a meta-analysis is presented in which we compared adopted children’s attachment relationships with the normative attachment distribution of nonadopted children raised by their biological parents, and - as a comparison - we also compared the attachment distribution of foster children with the normative distribution. The second and third parts of the thesis focus on the development of former foster and post-institutionalized children, 11 to 16 months old at arrival, two and six months after their adoption from China. Several salient developmental domains were studied: attachment, cognitive and motor development, physical growth, stress regulation, and social-emotional behavior. Show less
Aim of the dissertation: To expand the knowledge on the behavioural phenotypes, level of parenting stress and the relationship between child characteristics and parenting stress in five genetic... Show moreAim of the dissertation: To expand the knowledge on the behavioural phenotypes, level of parenting stress and the relationship between child characteristics and parenting stress in five genetic syndromes. The included syndromes are Angelman, CHARGE, Cornelia de Lange, Prader-Willi, and Rett syndrome. All syndromes are associated with intellectual disabilities. Method: Participants were children and adults with one of the syndromes and their parents, recruited through the Dutch Parent Support Groups. Parents filled out questionnaires concerning parenting stress and behavioural characteristics of their child. Additionally an interview regarding autistic traits of the child was administrated with parents. Main results: The behavioural phenotypes of the syndromes are described in detail. In all syndromes there is a high risk to display autistic traits. The syndromes can been seen as a risk factor for high levels of parenting stress. Specialized psycho-education on the behavioural strengths and weaknesses of a specific syndrome should be given to parents. Awareness on the high prevalence of autistic traits is important to be able to shape an optimum adaptive environment. Professionals should not only focus on the child with the syndrome, but also on the family system given the high stress levels for parents. Show less
One of the most remarkable aspects of multimodal perception is its coherence. Our conscious perception is unified at any given moment, although we acquire information from diverse channels with... Show moreOne of the most remarkable aspects of multimodal perception is its coherence. Our conscious perception is unified at any given moment, although we acquire information from diverse channels with distinct transduction mechanisms, and process it in different cortical areas not necessarily at the same time and pace. The problem of how the brain integrates the different types of information, which are processed in distinct cortical regions to a unified event, is referred to in literature as the binding problem (Triesman, 1996). The current thesis reflects a gradual inquest in order to reveal different aspects of the binding mechanism across multimodal perception and action. The empirical evidence suggests that feature integration emerges in a graded manner through intra and inter connections within and across modalities and domains, employing general principles (such as temporal overlap of feature activation), which capture the role of attention, salience and dominance among the features and the domains. Also, control processes are important in handling retrieved traces for efficient use. Nevertheless, the binding mechanism does not require a conscious or unified perception and unified perception is not the outcome of feature binding. Show less
The title of this study raises questions about the meaning and the significance of the words 'modernity', 'tradition' and 'Political Islam' in contemporary Iran. The purpose of this study is to... Show moreThe title of this study raises questions about the meaning and the significance of the words 'modernity', 'tradition' and 'Political Islam' in contemporary Iran. The purpose of this study is to reveal true meanings of the thoughts and practises of the post-revolution Iranian elites and intellectuals, in relations to and alongside the social events, to emphasize the existence of a modernisation process in the institution of state and the moderate re-interpretation of Islam in the religious establishment, which together have given rise to the distinctly Iranian features of political development. This study shall be in a socio-historical setting because political changes and social events in contemporary Iran are difficult to identify and impossible to understand unless their roots are discovered in their true locations. Show less
School refusal is an attendance problem characterized by a young person’s difficulty in going to school, accompanied by emotional distress on the part of the young person and parental attempts to... Show moreSchool refusal is an attendance problem characterized by a young person’s difficulty in going to school, accompanied by emotional distress on the part of the young person and parental attempts to return the young person to regular school attendance. Prolonged absence from school has serious short- and long-term consequences for young people, their families, and schools. Therefore, effective treatment of school refusal is essential. Numerous treatment outcome studies provide evidence for the efficacy of cognitive-behavioural therapy (CBT) for school refusal. Previous research has however indicated that adolescent school refusers may be particularly disturbed and harder to treat. An existing treatment for school-refusing children and adolescents was modified to better account for the impact of developmental variables on engagement in treatment. The studies presented in this dissertation describe the preparation, implementation, and evaluation of the resulting developmentally-appropriate CBT for adolescent school refusal. The treatment was associated with increased school attendance, reduced emotional symptoms, and increased adolescent and parental self-efficacy. Exploratory analyses revealed that several developmental factors were related to treatment outcomes, namely clinician developmental appropriateness, insight, and autonomy. Recommendations for research and clinical practice are made on the basis of these findings, and on the methodological strengths and limitations of the current research. Show less
This dissertation investigated the conditions under which the individual upward mobility of mem-bers of low status groups is likely to succeed and when it is likely to meet resistance. In addition,... Show moreThis dissertation investigated the conditions under which the individual upward mobility of mem-bers of low status groups is likely to succeed and when it is likely to meet resistance. In addition, it examines how upwardly mobile individuals can create such beneficial conditions. The results presented in this dissertation show support from fellow members of the low status group to be a key resource. Such ingroup support enables members of low status groups to persevere in the pursuit of individual upward mobility, even in the face of opposition from the high status outgroup. The results indicate that ingroup support is given to individuals the more they are perceived to represent the ingroup with their upward mobility. Moreover, the extent to which upwardly mobile individuals are perceived as representatives depends on how they associate with the low status ingroup. The results also show that the degree to which upwardly mobile individuals display their association with the low status group affects whether they meet resistance from the outgroup. While the high status outgroup is concerned about behavioral displays, it is less concerned with affective identification of upwardly mobile individuals of low status groups with their group. Explanations of these effects are offered. Show less
The Agta are a hunter-gatherer people inhabiting the last remaining tropical rain forest on the island of Luzon, in the north-eastern Philippines. Due to commercial logging operations, immigration... Show moreThe Agta are a hunter-gatherer people inhabiting the last remaining tropical rain forest on the island of Luzon, in the north-eastern Philippines. Due to commercial logging operations, immigration and conversion of forest into agricultural land, the Agta's resource base has come under increasing pressure over the past century. This ethnography analyses the way the Agta respond to these social and environmental changes. It shows that they face great problems with respect to health, nutrition, control over resources and participation in decisionmaking processes. It also shows, however, that by maintaining economic and residential flexibility and diversification, they succeed in continuing a hunter-gatherer way of life. Show less
Since the end of the twentieth century a broad and persistent movement away from centralized patterns of governance has become one of the defining trends in politics. In many new democracies the... Show moreSince the end of the twentieth century a broad and persistent movement away from centralized patterns of governance has become one of the defining trends in politics. In many new democracies the return to electoral politics has coincided with institutional reforms to promote decentralization. In Latin America, with its long and well-documented history of centralism, decentralization constitutes a departure from previous patterns of governance. This study seeks to shed light on the relationship between decentralization and political organization in Latin America, and aims to contribute to our understanding of how decentralization influences the way that conflicts in society are expressed, structured and managed through parties and party systems. Drawing on an in-depth study of Mexico as well as a comparative analysis of Latin American countries, it develops the argument that decentralization challenges political organization at the levels of party systems and organizations. The central contention is that a high level of decentralization can undermine the formation of nationalized party systems and cohesive parties. Decentralization affects the distribution of political and financial resources in the state and makes more resources available locally, and thus reshapes the context within which parties organize. Show less
Meerdimensionale ontvouwing is een analyse techniek die afbeeldingen maakt van twee sets van objecten, bijvoorbeeld van personen en producten, gebaseerd op de voorkeuren van de personen voor die... Show moreMeerdimensionale ontvouwing is een analyse techniek die afbeeldingen maakt van twee sets van objecten, bijvoorbeeld van personen en producten, gebaseerd op de voorkeuren van de personen voor die producten. De afstanden tussen de personen en de producten in de afbeelding dienen zo goed mogelijk te corresponderen met deze voorkeuren en wel zo dat een kleine afstand overeenkomt met een grote voorkeur, terwijl een grote afstand correspondeert met een geringe voorkeur. Ontvouwing heeft echter sinds zijn conceptie in de jaren zestig te maken met het zogenaamde degeneratieprobleem, waardoor de oplossingen perfect zijn in termen van de verliesfunctie (de afstanden geven de voorkeuren perfect weer), maar die volstrekt onbruikbaar zijn in termen van interpretatie (de perfecte weergave is nietszeggend). In dit proefschrift worden twee mogelijke oplossingen aangedragen voor het degeneratieprobleem. De meest algemene oplossing gebruikt een penaltyfunctie, die straft indien de oplossing dreigt te degenereren. Het algoritme is gebruikt voor de implementatie van PREFSCAL, het ontvouwingsprogramma van IBM SPSS STATISTICS. Met de controle over het degeneratieprobleem is de weg vrij gemaakt om het ontvouwingsmodel verder te ontwikkelen: extra, verklarende variabelen kunnen worden toegevoegd voor interpretatie en het doen van voorspellingen. De mate waarin gegevens mogen ontbreken zonder een doorslaggevende invloed te hebben op de eindoplossing, de afbeelding, is ook uitgebreid onderzocht. Show less
Managing diversity is an important issue on the agenda of policy makers, managers, and researchers. Past research has shown that diversity can enhance, but also disrupt team functioning. In this... Show moreManaging diversity is an important issue on the agenda of policy makers, managers, and researchers. Past research has shown that diversity can enhance, but also disrupt team functioning. In this dissertation, I attempt to more thoroughly understand this paradox by examining when and why diversity can enhance versus inhibit team learning and performance. These studies are grounded in the faultline perspective, which focuses on the demographic alignment of diversity attributes in a group. In addition, a typology and instrument for measuring team learning types was developed based on the topics that teams can learn about: task, process, and social learning. The relationship between faultlines and these types of team learning was examined. The results of this dissertation indicate that faultlines are not necessarily bad for team learning and performance, as is often assumed. For instance, faultlines had healthy effects on team learning when team members knew each other well and when the team had a constructive error culture. On the other hand, faultlines disrupted team learning and performance when team members perceived subgroups in their team. The results of this dissertation have important implications for future research and for the management of diversity in organizations. Show less
To figure out how to minimize the costs and maximize the benefits, we need to understand all dimensions and types of diversity. Research shows that some diversity characteristics have a larger... Show moreTo figure out how to minimize the costs and maximize the benefits, we need to understand all dimensions and types of diversity. Research shows that some diversity characteristics have a larger impact than others (Tsui, Egan, & O’Reilly, 1992). One type of diversity that could have a significant impact on workgroup interaction is national diversity. Every member, however, enters the workgroup with a set of personal and social attitudes and beliefs. These pre-programmed attitudes and beliefs may largely affect one’s perceptions and thus behaviors. Whether diversity will have positive or negative consequences may be explained by investigating attitudes of the group members. For this reason, I investigate nationalistic attitudes as exacerbators of conflict in nationally diverse workgroups. A set of studies investigates propositions that members with diverse national backgrounds, especially if they have strong nationalistic attitudes, are likely to experience more conflict than nationally homogenous groups (and/or if members do not hold strong nationalistic views). Other moderators of conflict and outcomes in nationally diverse workgroups that I examine using multiple methods (field, scenario, and lab studies) include social distances, national stereotypes, similarity preferences, and perceived respect. Show less
In dit proefschrift staat ouderschap in de vroege kindertijd centraal, onder andere de reacties van volwassenen op het huilen van baby’s. Voor baby’s is huilen één van de belangrijkste manieren om... Show moreIn dit proefschrift staat ouderschap in de vroege kindertijd centraal, onder andere de reacties van volwassenen op het huilen van baby’s. Voor baby’s is huilen één van de belangrijkste manieren om te communiceren. Zo laten ze weten dat ze ergens behoefte aan hebben of zich niet lekker voelen. Maar niet alle ouders reageren op een sensitieve, liefdevolle manier: voor sommige ouders is het huilen van hun kind zo stressvol dat ze eerder op een hardhandige wijze reageren. In deze studie is onderzocht hoe volwassenen reageren op het huilen van een baby. Daarbij werd een standaard huilfragment van een pasgeboren kind gemanipuleerd en op verschillende hoogten afgespeeld. De toonhoogte van het huilgeluid en de manier waarop volwassenen het huilen interpreteren, bleken belangrijk te zijn. Hoge huilgeluiden vormen een risicofactor voor het stevig willen aanpakken van het kind. Zieke en premature kinderen hebben vaker zulke hoge huiltonen. Ook is onderzocht of verschillen in reactie op huilen erfelijk zijn. Dat is inderdaad het geval, maar niet voor alle aspecten van reageren op huilen. Verschillen in sensitieve reacties waren erfelijk bepaald, maar de neiging om het kind op een hardhandige manier aan te pakken niet. Show less
This thesis deals with the negative perceptions of socially anxious youth in three different cognitive domains: (a) interpretation of ambiguous social situations, (b) self-evaluation of social... Show moreThis thesis deals with the negative perceptions of socially anxious youth in three different cognitive domains: (a) interpretation of ambiguous social situations, (b) self-evaluation of social skills and nervous behaviors, and (c) perception of physical arousal during social situations. It also addresses the issue of whether socially anxious youth's negative cognitions are justified as based on objective sources of information, such as independent observers, same age peers and actual physical responding. Show less
This thesis studies the normal developmental pattern of social evaluative fears from childhood to adolescence. We have investigated age differences in self-reported social fears and physical... Show moreThis thesis studies the normal developmental pattern of social evaluative fears from childhood to adolescence. We have investigated age differences in self-reported social fears and physical responses during a public speaking task. In addition, youth's perceptions of speaking in public were studied through a short interview. Finally, two aspects of adolescent development are highlighted, namely resistance to peer influence and self-restraint, in the two concluding chapters. The main finding of the thesis is that social evaluative fears seem to increase with age. However, future research needs to develop more developmentally sensitive measures and further investigate the underlying processes of this increase. Show less
