Research master thesis | Archaeology (research) (MA/MSc)
under embargo until 2024-10-19
2024-10-19T00:00:00Z
During the early modern period (1500-1800 CE), Europe was plagued by syphilis, a venereal infection caused by the bacteria Treponema pallidum, resulting in chronic and debilitating symptoms....Show moreDuring the early modern period (1500-1800 CE), Europe was plagued by syphilis, a venereal infection caused by the bacteria Treponema pallidum, resulting in chronic and debilitating symptoms. Desperate to resolve the infection, patients were often subjected to prolonged and extensive treatments with toxic mercury. Unfortunately, osteoarchaeological study of syphilis is challenging due to the limited skeletal visibility of the infection. Moreover, historical evidence is sparse and often influenced by sociocultural stigma attributed to the venereal nature of the disease. This scarcity of data on syphilis in the early modern period has limited more holistic research into the disease and its treatment. Therefore, this study adopted a multidisciplinary approach to investigate syphilis and its treatment at St. Gertrude’s infirmary (1382 - ca. 1611) in Kampen, the Netherlands, where presence of the disease has been previously reported. Human skeletal remains (n=79) were re-examined with a focus on treponemal disease, following the scoring system laid out by Harper et al. (2011). The potential therapeutical use of mercury was investigated by conducting archival research and multiple trace elemental analyses. Using portable X-Ray Fluorescence Spectrometry (pXRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), subsamples of the skeletal assemblage were assessed on the presence of mercury in human bone. Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX) was conducted to assess the potential uptake of mercury in dental calculus on the teeth. Osteoarchaeological study identified several diagnostic cases of treponemal infection at the site (n=5 or 6.33%), as well as a number of cases with lesions suggestive of treponemal disease. This finding demonstrates the influence of treponemal disease, likely attributable to venereal syphilis, at St. Gertrude’s infirmary in Kampen, especially when compared to the prevalence of the disease in human skeletal assemblages from similar Dutch sites. Research into historical archives indicated that mercury was indeed used therapeutically in Kampen during the 18th century. However, it showed no direct evidence for syphilis or mercury treatment at St. Gertrude’s infirmary in the period of interest (1382 – ca. 1611). Unfortunately, elemental analyses revealed no substantial evidence for significantly elevated mercury concentrations, although interesting trends were found. In particular, both pXRF and SEM-EDX analyses did not result in absolute and quantifiable mercury concentrations. While ICP-MS analysis showed absolute concentrations of mercury in a subsample of bone material, interpreting and contextualising these results remains challenging. These observations may be explained by a lack of available mercury treatment in Kampen or a preference for other treatment methods. Nonetheless, this study helps to understand syphilis and its treatment in the early modern Netherlands and provides an evaluation of chemical analyses to detect mercury in archaeological bone.Show less
Research master thesis | Archaeology (research) (MA/MSc)
closed access
Lithics are often one of the few materials from the Paleolithic that withstood the passage of time. Archeologists rely on them when they try to understand what happened in the past. Over the past...Show moreLithics are often one of the few materials from the Paleolithic that withstood the passage of time. Archeologists rely on them when they try to understand what happened in the past. Over the past centuries, lithic research has changed and in the last decennia the use of Machine Learning and 3D geometric morphometric (3DGM) analysis has been explored. In 2021, Archer et al. published a paper in which they explored the possibility of 3DGM analysis. With the help of Machine Learning, their model was trained with an experimental reference collection consisting of Levallois, discoidal and laminar debitage. As a result, the model could classify the technology of 73 – 77 % of the remaining experimental collection correctly. With a traditional analysis, around 20 – 30 % of the flake assemblage is identified. This would indicate that a much larger percentage of the assemblage could be classified with 3DGM analysis. However, this had never been tested on an archeological collection. In this thesis, the late Middle Paleolithic lithics of sublayers EGB and EGC of Quinçay are studied with a focus on flaking technologies. This is done through a traditional analysis consisting of an attribute analysis and a chaîne opératoire analysis and a 3DGM analysis. This is important for two main reasons: 1. Since 3DGM analysis of flaking technologies has never been applied on an archeological collection before, this research might provide valuable insights on how 3DGM analysis can be useful for understanding flaking technologies of archeological lithic collections, 2. The sublayers EGB and EGC of Quinçay have never been studied in detail before, and might provide more insights into the nature of the archeological sequence at Quinçay. Interestingly, the results of the traditional analysis and the 3DGM analysis revealed quite some differences. In the traditional analysis, discoid seemed to be the most common reduction method in the assemblage, this was followed by laminar reduction. However, in the 3DGM analysis, most of the flakes were classified as Levallois flakes. The model seemed to have the most difficulties with recognizing discoid products. The reason for the differences in classification between the traditional analysis and 3DGM analysis, could possibly be result of how the experimental collection was set up and the model was trained. In this thesis, multiple suggestions are proposed that could potentially help with improving the model in such a way that it could be more beneficial when using it on an archeological collection. The advantages and disadvantages that come with 3DGM analysis are also touched upon. By incorporating this innovative approach when studying the late Middle Paleolithic lithics from Quinçay, it is explored how 3DGM analysis can potentially help researchers with the analysis of lithics. As Machine Learning and Artificial Intelligence become more intensively used in the future, it is not unlikely that it will start to play an important role in lithic analysis as well.Show less
Research master thesis | Archaeology (research) (MA/MSc)
under embargo until 2024-08-31
2024-08-31T00:00:00Z
Stable carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) isotopes are well-established proxies for the reconstruction of past diet and environment. δ13C and δ18O can be used to reconstruct the...Show moreStable carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) isotopes are well-established proxies for the reconstruction of past diet and environment. δ13C and δ18O can be used to reconstruct the plant-based diets of animals and seasonal environmental patterns. These isotopes are regularly measured in the non-organic component of tooth enamel, which is highly resistant to diagenetic alteration. Likewise, δ15N can be used to reconstruct trophic level and food webs. Up until recently, δ15N could only be measured on relatively young samples (<100,000 years old), because it requires organic material, usually bone collagen or dentin, which rarely preserves in the fossil record. However, in 2021, an oxidation-denitrification method was developed. This method allows for the measurement of the nitrogen isotopic composition of the organic material trapped in the crystalline structure of (fossil) tooth enamel. Thus, we can now measure δ13C, δ15N, and δ18O on the same aliquot of tooth enamel. Here, combined δ13C, δ15N, and δ18O isotope data from tooth enamel of 14 serially-sampled fossil equid (Equus sp.) third molars from the ~120,000-year-old Middle Paleolithic Neanderthal site of Neumark-Nord 2, Germany, is presented. Each tooth was sampled along the growth axis and yielded up to 26 sub-samples (total n = 259). Neumark-Nord is a well-preserved archaeological site with a rich vertebrate fauna. It has yielded a large isotopic dataset, which includes some of the oldest stable carbon and nitrogen isotope measurements on bone collagen. This study allows us to expand the isotopic dataset of Neumark-Nord 2 by serially-sampled data, which enables us to reconstruct seasonality for the Last Interglacial (Eemian; MIS 5e/5d transition). δ13C and δ18O of all enamel samples (n = 259) was measured using the cold trap method. Based on these isotope patterns, 72 samples (including all serial measurements of three of the equid teeth) were selected for δ15N measurement, to assess potential seasonal variation in the δ15N values of the enamel. The enamel δ13C, δ15N, and δ18O results are consistent with previously published equid collagen δ13C, δ15N, and bulk enamel δ18O values. A clear seasonal signal is present in the δ18O values of each tooth, with higher values in summer than in winter. This seasonal signal is absent in both the δ13C and δ15N values. This study shows that there is no strong effect of seasonal variation detectable in the δ15N values of nitrogen isotopes in the enamel of equids in temperate environments. This suggests that, in order to measure an accurate average δ15N value, bulk samples of tooth enamel from equids – and likely other large herbivores – in temperature environments do not need to cover an entire year of growth. In addition, the correlation observed between δ13C and δ15N enamel values seems to indicate that, in such environments, the mechanisms controlling carbon and nitrogen isotope fractionation are positively related. Lastly, this study improves the time-resolution of the Neumark-Nord 2 isotopic dataset, allowing for a better reconstruction of the past ecosystem by providing seasonal data.Show less
Research master thesis | Archaeology (research) (MA/MSc)
closed access
Towards the end of the third millennium BC, Europe underwent significant transformations. The production of bronze would change the economic, social, and political landscape, and marked the period...Show moreTowards the end of the third millennium BC, Europe underwent significant transformations. The production of bronze would change the economic, social, and political landscape, and marked the period known as the Bronze Age. The Bronze Age witnessed the establishment of a globalized network, facilitated by extensive exchange networks. Bronze, a highly sought-after alloy made of copper and tin, played a crucial role in these developments. It became the predominant material for crafting tools, weapons, and ornaments, leading to its widespread use across Europe, even in regions far from the sources of copper and tin. The increase in trade led to theories that human mobility increased significantly during this period. Bronze Age human has been subject to many studies, which generally seem to indicate that mobility did increase, and that it was mainly females who were mobile. To investigate mobility patterns during the Bronze Age, strontium isotope analysis has proven invaluable. Although the process of cremation, which was the dominant burial method at the time, posed challenges for mobility studies, recent findings have shown that strontium isotope analysis on calcined bone can yield reliable results. This discovery has opened the door for studying mobility in cremation contexts. Despite speculation about population movement in the Netherlands during the Bronze Age based on the analysis of non-local objects, no research has been conducted in the country utilizing strontium isotope analysis to study it. For this research, strontium isotope analysis was performed on a Middle Bronze Age population from Apeldoorn-Wieselseweg. Samples of the pars petrosa, long bone, rib, and dentine were used where possible. By providing new strontium isotope data, this research hopes to gain a better understanding of human mobility during the Bronze Age in the Netherlands, and place it in a wider European context. The patterns that were observed in the results, align with the broader discussions on Bronze Age human mobility in Europe. The presence of non-local females supports the theories on female exogamy and patrilocal organisation, suggesting that these females likely migrated to the community through marriage exchange. The presence of a non-local male and child could be evidence for a fostering system. Intra-individual variation has also been observed at the site, which could be an indication of mobility. These results are similar to those from other studies on Bronze Age human mobility. However, more research is needed on Bronze Age populations in the Netherlands to gain a better understanding of the movement of people in local, and global contexts.Show less
Research master thesis | Archaeology (research) (MA/MSc)
open access
The human hand is a complex structure that is heavily involved in many everyday activities. As such, it can serve as a useful area for activity reconstruction in the past. Though its function and...Show moreThe human hand is a complex structure that is heavily involved in many everyday activities. As such, it can serve as a useful area for activity reconstruction in the past. Though its function and evolution have long been studied, parts of it still need to be better understood. There is evidence to suggest that the fifth ray of the hand contributes significantly to grip strength and stability in a way that has so far gone largely ignored. The aim of this study is two-fold. First, it seeks to gain a better understanding of the function and use of the fifth digit in habitual activity on the basis of three postmedieval Dutch populations. Second, it investigates habitual activity and occupation among the individuals that belonged to these communities to gain a better understanding of the lives led by people in the post-medieval Netherlands. In order to achieve those goals, the study analyses activity patterns among hand entheses through the “Validated Entheses-based Reconstruction of Activity” (VERA) method. The method is applied to 3D scans of the hand bones of 43 adult individuals. Multivariate statistics, including principal component analysis, are used for the analysis of the entheseal attachment sizes. The analysis showed that the muscles of the fifth ray are recruited in both precision and power grips in different capacities. It suggests that the fifth ray is an important supporting structure that aids in the execution of power and precision grips through its opposing position to the thumb. It is also used to provide stability by pulling it towards the other fingers. The results of this study support the assumption that the fifth ray of the hand plays a crucial role in everyday manual activity. They also suggest that a deeper understanding of its role could provide additional insights into different kinds of grasping activities in the past. The analysis further showed that the three different groups exhibit different activity patterns. The lower-class urban individuals or Arnhem exhibit a trend towards more intense power grasping, while the higher-class urban individuals from Zwolle showed a tendency for precision grasping activity. This is consistent with historical records that suggest the Zwolle individuals had worked as merchants, investors, and in similar professions, while the working poor in the city of Arnhem were probably working in factories and in the local tobacco production. The individuals from the rural community of Middenbeemster fell somewhat surprisingly in the middle of the other two groups, with a sizeable number of individuals exhibiting precision gripping patterns. This suggests that, despite this community having mainly revolved around dairy farming, individual life experiences were likely quite varied. Future analyses of the fifth ray should expand on the groundwork laid in this study by increasing the sample size, looking into individuals from different contexts and time periods, and looking into potential connections between the fifth ray and the fourth ray, wrist, and forearm.Show less
Research master thesis | Archaeology (research) (MA/MSc)
open access
During the Michelsberg period (4,400 to 3,500 cal BC), harvesting tools were rarely discovered at excavations in North-Western Europe, be it in Belgium, Southern Netherlands, Northern France, or...Show moreDuring the Michelsberg period (4,400 to 3,500 cal BC), harvesting tools were rarely discovered at excavations in North-Western Europe, be it in Belgium, Southern Netherlands, Northern France, or Northern Germany. But cereal consumption was widely practiced, as grains discovered in these settlements show. Several researchers have, over the last 50 years, highlighted this discrepancy of missing harvesting tools and presence of cereal grains. They have tried to explain that, during this 900-year Michelsberg period and over a surface of several hundred square kilometres, cereals had to be collected either with the help of bare hands or with tools made from other, organic materials. But so far none of such traces have been detected in excavations. The aim of this paper is to present, through experimental archaeology and the analysis of use-wear traces, that tools made from organic material such as shell, wood and bone could have been used to gather cereal plants. To achieve this aim, a large variety of experimental tools have been created and tested on different fields of typical cereal types of the Michelsberg period. These were Triticum monococcum or einkorn wheat, Triticum dicoccum or emmer wheat, Triticum aestivum or naked wheat, and Hordeum vulgare or barley. The result of these harvest experiments has been analysed quantitatively with regards to the achieved harvested surface, grain yield, and harvesting speed. The use-wear traces created by these different cereal plants during the harvest have also been studied. They are polish, striations, edge rounding and edge damages, which have been evaluated under different microscopes to reveal typical shapes these cereals leave on tools. The results of that harvesting experiment and use-wear analysis are presented in this thesis and could serve as reference to interpret archaeological material differently in the future.Show less
Research master thesis | Archaeology (research) (MA/MSc)
open access
Demeter, the goddess of the harvest, agriculture, and fertility, is one of the twelve main Olympic gods who was worshipped by the Greeks, amongst others, around 2500 years ago. She played an...Show moreDemeter, the goddess of the harvest, agriculture, and fertility, is one of the twelve main Olympic gods who was worshipped by the Greeks, amongst others, around 2500 years ago. She played an important role in Greek religious practices and rituals, as she provides one of the basic necessities of life: food. From the 8th century BC, the Greeks started to venture out of the motherland into the wider area of the Mediterranean, Black Sea, and Asia Minor to create settlements, or as they called it apoikiai: home away from home. When taking location, time and local perceptions of religion into account, it can be concluded that even in Greece, there was no uniform cult of Demeter. Each cult was practised in a sanctuary wherein different aspects and attributes of the goddess were highlighted. This is also the case in the apoikiai, where the Greek settlers encountered different cultures. This thesis aims to analyse the changes in the cult of Demeter after the worship of the goddess spreads across the Mediterranean. Variations in worship practice, rituals and beliefs will be explored, simultaneously highlighting the geographical and temporal development of the cult. It is significant to study the local, regional and Panhellenic varieties of the cult of Demeter, as it allows for a deeper understanding of how religious beliefs and cult practice changed. Furthermore, it shows which elements of cult practice are influenced by either geographical, temporal or cultural aspects. This thesis adds to the current knowledge of the worship of Demeter by comparing cult practice in different sanctuaries dedicated to the goddess to see their similarities and differences. Several case studies were chosen as proxies. Two well-known sanctuaries located in Greece are used for the basis of the comparison: the sanctuary of Demeter and Kore at Eleusis and the sanctuary of Demeter and Kore at Acrocorinth. Three other case studies were chosen from the island of Sicily, where Demeter and her daughter Persephone were very important goddesses. These sanctuaries include the sanctuary of Demeter Malophoros at Selinus, the sanctuary of Demeter Thesmophoros at Bitalemi, Gela and the sanctuary of Demeter at S. Anna, Akragas. By performing literary research, in which literary, epigraphical and archaeological evidence will be considered, it will be studied how cult practice looked like in each sanctuary. An elaborate catalogue will be created, in which several categories, including the cult epithet, place of worship, cult objects, religious feasting and cult participants, will be studied in detail. This catalogue will form the basis of the comparison between the different sanctuaries studied in this thesis. First, the sanctuaries located in the same regions will be compared to one another, followed by the Panhellenic comparison where all sanctuaries are equated to study the likenesses in the worship of the same goddess. It is expected that this research will reveal both similarities and differences in the cult practice of Demeter in Ancient Greece and Sicily, showing the influence of geographical and temporal factors. Through the interaction between the settling Greeks and other (indigenous) cultures, ideas on worship may be exchanged, resulting in a more ‘shared’ world. In this world, the same goddess is worshipped in numerous sanctuaries spread across a vast area in a variety of ways, demonstrating the complexity of the worship of Demeter.Show less
Research master thesis | Archaeology (research) (MA/MSc)
open access
The Tang (唐) dynasty (618 – 907 C.E.), and to a lesser extent the Sui (隋) dynasty (589 – 617 C.E.) that directly preceded it, is often considered to be China’s premier ‘Golden Age’, the height of...Show moreThe Tang (唐) dynasty (618 – 907 C.E.), and to a lesser extent the Sui (隋) dynasty (589 – 617 C.E.) that directly preceded it, is often considered to be China’s premier ‘Golden Age’, the height of its cultural expression and the peak of its international trade. By contrast, the preceding period of disunity, often called the Six Dynasties period (六朝) (220 – 589 C.E.), stands out as a time of great chaos, uncertainty, and isolation in the minds of many both today and at the time of the Tang. A clear schism thus exists in our image of China in the first millennium C.E.. Yet this image comes to us mainly from written sources both ancient and modern, and is rarely independently analysed based on the archaeological remains of the periods. The aim of this thesis is to place archaeological material from China, which played a role in the ancient Silk Road trade network during the first millennium C.E., on a level with the historical sources, to find where they may coincide with or contradict each other, thus enriching our understanding of China’s role in the world of the first millennium C.E.. In order to do so, the thesis poses the question whether this schism of China’s active participation in international trade between the Six Dynasties and Tang periods can be traced in the archaeological evidence of trade from these periods, by studying a selection of Chinese archaeological material dating to the first millennium C.E. and analysing it through the lens of a world-systems and globalisation theoretical framework. The material used comes from Paul Ruitenbeek Art Gallery in Amsterdam, as well as several museum collections and academic and non-academic publications, as this is a topic not widely explored in academia. The Case Studies are organised into the themes of ‘Trade and travel represented’, ‘Exported items: luxury and practicality’, ‘Currency on the Silk Roads’, and ‘Influential style and beauty’. Ultimately, based on the combination of historical context, previous research, the case studies, and the theoretical framework, the conclusion is reached that while significant changes can be observed in China’s political situation and its involvement within the Silk Road trade network throughout the first millennium C.E., and these developments are at times closely influenced by each other, they are not intrinsically linked, as it was in fact the adaptability of the network and its various players that allowed the network to persist over such a long 128 period of time. Further research is needed to gain a true understanding of China’s role in the Silk Road trade network during the first millennium C.E..Show less
Research master thesis | Psychology (research) (MSc)
closed access
Background: Research has identified psychological factors as important predictors of highly prevelant persistent somatic symptoms (PSS). However, this research is generally not based on primary...Show moreBackground: Research has identified psychological factors as important predictors of highly prevelant persistent somatic symptoms (PSS). However, this research is generally not based on primary care data and general practitioners (GPs) experience difficulties identifying PSS in their patients. Awareness of the psychological risk factors noted in readily accessible electronic medical records (EMRs) might aid GPs with earlier discovery and treatment. Aim: The objective was to examine the predictive value of psychological registrations in primary care for PSS onset. Method: We employed a retrospective longitudinal cohort design. EMR data of Dutch primary care patients were allocated into different subsamples according to registrations of irritable bowel syndrome (IBS), chronic fatigue syndrome (CFS), fibromyalgia (FM), and a combination of these registrations (COMBI) with age and sex-matched non-PSS cohorts. Candidate predictors were registered psychological symptoms, mental health referrals, and psycho-pharmaceuticals registered prior to PSS onset. The relevance of each candidate predictor was determined via L1 regularization in a logistic Lasso regression. The resulting prediction models’ performance was assessed via area under the curve (AUC). Results: The AUC indicated a fair classification performance for IBS (AUC IBS = .77), and good classification performances for CFS, FM, and COMBI (AUC CFS = .82, AUC FM = .88, and AUC COMBI= .87). The IBS-, CFS-, FM-, and COMBI-models, retained a total of 27, 12, 22, and 15 predictors, respectively. The strongest predictor per model was registration of sexual dysfunction for IBS (OR = 4.0), concentration disorder for CFS (OR = 2.4), neurasthenia for FM (OR = 3.0), and concentration disorder for COMBI (OR = 3.8). Neither of these predictors was unique to one specific model. Each final model retained mental health referrals, psycho-pharmaceuticals, and certain psychological symptom registrations as valuable predictors. Based on shared predictors IBS and FM had the closest models while IBS and CFS models were the most dissimilar. Discussion: These findings indicate that several psychological registrations are valuable predictors for onset of IBS, CFS, and/or FM. Therefore, GPs should consider the according predictors when screening for PSS. Future research could examine the comparatively low classification performce for IBS and psychological factors outside of primary care across PSS subtypes.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Background: Theoretical models propose that parenting practices play a role in the development and maintenance of child depression. However, previous meta-analytic findings indicated that parenting...Show moreBackground: Theoretical models propose that parenting practices play a role in the development and maintenance of child depression. However, previous meta-analytic findings indicated that parenting accounted for only 5-11% of the variance in childhood depression, with varying effects for different types of parenting behaviors. Research Question: The current study aimed to investigate the association between observed negative/positive parenting behavior, childhood depression, and child gender, while controlling for the confounding effects of type of informant and assessment approach for childhood depression. Method: Two meta-analysis were conducted for the negative parenting – childhood depression and positive parenting – childhood depression association, while including moderating and confounding variables. The current study included thirty articles in total, with nineteen examining negative parenting behaviors and twenty-three examining positive parenting behaviors. Results: Observed negative parenting behavior was positively and observed positive parenting behavior was negatively related to childhood depression, with overall small effect sizes. Type of parenting behavior, child gender, and assessment approach for childhood depression did not moderate the associations. Type of informant for childhood depression explained some variance in the positive parenting – childhood depression association. Conclusions: Parenting interventions for childhood depression might aim to improve a broader range of parental behaviors. Future research is advised to compare actual to perceived parenting behaviors and investigate the direction of the parenting – childhood depression association, while adopting a multiple levels of analysis perspective. This could possibly contribute towards developing most effective personalized interventions for childhood depression, while lowering the high burden of depression.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Having an extra sex chromosome is known as sex chromosome trisomy (SCT). This may result in 47,XXY, 47,XXX, or 47,XYY. Previous research suggested that social attention to the eyes is reduced in ...Show moreHaving an extra sex chromosome is known as sex chromosome trisomy (SCT). This may result in 47,XXY, 47,XXX, or 47,XYY. Previous research suggested that social attention to the eyes is reduced in (young) adults with SCT and that individuals with SCT have more autistic characteristics compared to typically developing (TD) controls. It was unknown whether the group differences were also present in early childhood. The current study aimed to explore social attention, autistic traits, and their relation in three subgroups of children with SCT (47,XXY, 47,XXX, and 47,XYY; N = 70), aged 3 to 7 years, in comparison to TD peers (N = 62). Social attention to the eyes was measured using three eye-tracking video paradigms: A single-face condition, a multiple-face condition and a social interaction condition. Autistic traits were measured using the Social Responsiveness Scale-Second Edition. Results showed a difference in social attention between children with SCT and TD children during the social interaction condition. There was no difference in social attention between the SCT subgroups. The SCT group showed more autistic traits than the TD group and the 47,XXX subgroup had more autistic traits than the 47,XXY subgroup. There was a significant relation between social attention during the single-face condition and autistic traits in the 47,XYY subgroup only. Implications of these findings are discussed in relation to the importance of monitoring socio-cognitive challenges related to SCT in early childhood.Show less
Research master thesis | Psychology (research) (MSc)
closed access
The optimal strategy in a semantic verbal fluency (SVF) task is to focus on one semantic subcategory at a time and adaptively switch from one subcategory to another. This task has therefore been...Show moreThe optimal strategy in a semantic verbal fluency (SVF) task is to focus on one semantic subcategory at a time and adaptively switch from one subcategory to another. This task has therefore been used as a measure of self-directed executive functioning. Previous studies have found that SVF performance improves through childhood and adolescence. This developmentalimprovement has been observed both in the total number of words produced during the task and in switching between subcategories. The present online study tested the hypothesis that the agerelated improvement in SVF performance is partly driven by an improved ability to select between competing word representations. The study included three age groups: 8–10-year-olds (n=26), 12–14-year-olds (n=17), and young adults (n=31). The semantic blocking effect in the blocked cycling naming task was used as a measure of selection abilities. Measures of vocabulary and general processing speed were included as control variables. Age-related differences in SVF performance were only partly replicated: there were signs of age-related differences in the total word count but not in switching. The semantic blocking effect was replicated across age groups. However, there were no signs of age-related differences in the magnitude of this effect, suggesting that word selection abilities did not differ between age groups. Moreover, the magnitude of the semantic blocking effect did not predict SVF performance. Thus, although further research is needed, the present study does not support the hypothesis that the age-related improvement in SVF would be driven by an improvement in selection abilities.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Using a wide variety of clinical questionnaires might hamper the communication between clinicians and researchers in Routine outcome monitoring (ROM). Linking test scores to T scores as a common...Show moreUsing a wide variety of clinical questionnaires might hamper the communication between clinicians and researchers in Routine outcome monitoring (ROM). Linking test scores to T scores as a common metric might be a solution. Item response theory (IRT) is the preferred way to estimate T-scores. However, required software and a large dataset is needed for that. In this thesis, two methods were used to arrive at a common metric for often used questionnaires and their subversions: the BSI, BSI-18, the DASS-42 and the DASS-21. As one method, we used an IRT approach to estimate theta-based T-scores, leading to crosswalk tables. For the second approach, conversion formulas were estimated for raw scores to calculated T-scores based on the best-fitting regression equation between the raw scores and the previously estimated theta-based T-scores. Crosswalk tables and conversion formulas are both alternative ways to link individual scores to a common metric. It was investigated if conversion formulas are valid by comparing calculated T-scores with theta-based T-scores. The agreement between calculated T-scores and theta-based T-scores were high for all questionnaires except the DASS-42. The agreement was also lower at the extreme ends of the questionnaires (T= < 50 and T= >75). All in all, conversion formulas seem to be a good alternative for estimating a common metric. Offering different options to calculate common metrics can help in improving the communication between professionals in the clinical field. Increased involvement and better communication in ROM is able to increase the quality of mental health care.Show less
Research master thesis | Psychology (research) (MSc)
closed access
This study aimed to investigate the effectiveness of a newly developed dynamic test for phonological and prosodic awareness in children with and without dyslexia. Additionally, the impact of...Show moreThis study aimed to investigate the effectiveness of a newly developed dynamic test for phonological and prosodic awareness in children with and without dyslexia. Additionally, the impact of reading self-concept was investigated. 30 children with dyslexia and 48 without dyslexia (Mage = 10.55) were included. The study consisted of two sessions: In the first session, all children completed a reading self-concept questionnaire. In the second session, the children were randomized into an experimental or control condition for a test-training-test design. Children in the experimental condition received a dynamic training between pre-test and post-test, the control condition did not. Results indicated that trained children had improved more on prosodic awareness than non-trained children. This effect was not found for phonemic awareness. Dyslexia diagnosis did not influence improvement. Furthermore, children with dyslexia had lower reading self-concept compared to children without dyslexia. However, reading self-concept was not related to improvement during a dynamic test, and dyslexia diagnosis did not moderate this relationship.Show less
Research master thesis | Psychology (research) (MSc)
open access
Identical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time,...Show moreIdentical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time, unexpected objects are found to elicit a stronger neural response. These effects can be explained by predictive coding accounts of visual processing, presenting perception as a process of minimizing the difference between predicted and observed sensory input. However, as expectation and task-relevance are often conflated, it is insufficiently clear how these factors influence sensory processing in conscious perception. The current study aimed to investigate the relative influence of expectation and task-relevance on behavioral and neural measures of perception. During two EEG sessions, participants performed a task in which they discriminated between masked face and house images while we independently manipulated expectation and task-relevance. We find that images were more often correctly recognized when they were expected or task-relevant. In addition, we used multivariate pattern analysis to show that a classifier trained on sensory representations of face and house stimuli is better able to distinguish between expected or task-relevant face and house images than between unexpected or task-irrelevant images. These results suggest that expectation and task-relevance have independent effects on sensory processing. Finally, our results show that cue-based manipulations may activate sensory templates even before stimulus onset. We therefore recommend that future studies manipulate expectation and task-relevance without the use of explicit cues.Show less
Research master thesis | Psychology (research) (MSc)
closed access
Background: Information processing impairments are frequently observed in posttraumatic stress disorder (PTSD). Yet, the neurobiological underpinnings of these impairments are not well understood....Show moreBackground: Information processing impairments are frequently observed in posttraumatic stress disorder (PTSD). Yet, the neurobiological underpinnings of these impairments are not well understood. Mismatch negativity (MMN) is an event-related potential (ERP) that is thought to represent early sensory change detection. Previous electro-encephalography (EEG) studies on MMN in PTSD have revealed inconsistent results, with findings of both enhanced and reduced MMN amplitudes. Objective: We aimed to extend previous MMN findings to trauma-affected refugees, a PTSD population that often presents with complex, chronic, and severe forms of PTSD. Methods: We examined amplitudes and latencies of MMN in 25 refugees with PTSD and 20 healthy refugee controls matched on age, sex, and country of origin. We employed an MMN paradigm with three types of sound deviants: frequency, duration, and frequency-duration combined. Furthermore, associations between MMN amplitudes and clinical scores of PTSD and functioning were examined. Results: There were no significant differences in MMN amplitudes or latencies in PTSD versus control participants, following any of the deviants. Exploratory analyses revealed a significant sex-by-group interaction effect on MMN following the frequency-duration combined deviant, with enhanced MMN amplitudes in women with PTSD compared with controls. This pattern of findings was not found for the other deviants. Significant associations were found between MMN amplitudes and clinical scores in women only. Conclusion: Our findings point towards sex-differences in the underlying mechanisms of PTSD in refugees, highlighting the need of considering sex in future MMN studies.Show less
