Clinching is a joining process that is becoming more and more important in industry due to the increasing use of multimaterial designs. Despite the already widespread use of the process, there is still a need for research to understand the mechanisms and design of clinched joints. In contrast to the tool parameters, process and material disturbances have not yet been investigated to a relatively large extent. However, these also have a great influence on the properties and applicability of clinching. The effect of process disturbances on the clinched joint are investigated with numerical and experimental methods. The investigated process variations are the history of the sheets using the pre-hardening of the material, different sheet thicknesses, sheet arrangements and punch strokes. For the consideration of the material history, a specimen geometry for pre-stretching specimens in uniaxial tension is used, from which the pre-stretched secondary specimens are taken. A finite element model is set up for the numerical investigations. Suitable clinching tools are selected. With the simulation, selected process influences can be examined. The effort of the numerical investigations is considerably reduced with the help of a statistical experimental design according to Taguchi. To confirm the simulation results, experimental investigations of the clinch point geometry by using micrographs and the shear strength of the clinched joint are performed. The analysis of the influence of difference disturbance factors on the clinching process demonstrate the importance of the holistic view of the clinching process.

Das arabische Wort „Khalifa“ in der Bedeutung „Stellvertreter“ oder „Nachfolger“ wird im Koran, dem heiligen Buch der Muslime an zwei Stellen verwendet (Sure 7, Vers 69 und Sure 38, Vers 26). Darin wird der Mensch als der Stellvertreter Gottes auf Erden bezeichnet. Im historischen Kontext entsteht der Begriff nach dem Tod des Propheten Muhammad im Jahr 632. Die ersten vier Nachfolger in der politischen Führung der Gemeinde werden in der sunnitischen Geschichtsschreibung als die „Raschidun“ (die Rechtgeleiteten) bezeichnet. In dieser Zeit, also zwischen 632 und 661, entsteht auch der Begriff „Amir al-Muminin“ (Beherrscher der Gläubigen) als Titel des Kalifen, mit dem die Herrscher auch angeredet wurden. Die Frage der Nachfolge des Propheten Muhammad entwickelte sich zu einem grundlegenden Streitpunkt innerhalb der jungen muslimischen Gemeinde. Aus diesen Auseinandersetzungen heraus entstand dann die konfessionelle Spaltung der muslimischen Welt in die sunnitische Mehrheit und die schiitische Minderheit. Grundlegend gibt es Gemeinsamkeiten sowie Unterschiede zwischen den zwei Hauptströmungen der islamischen Gemeinde, den Sunniten und Schiiten. Der Umfang der Meinungsverschiedenheiten zwischen Sunniten und Schiiten sind mehr als deren Ähnlichkeiten, obwohl diese Unterschiede auf den ersten Blick nicht erkennbar sind. Die Wurzeln all dieser Differenzen sind darauf zurückzuführen, dass die Schiiten nach dem Hinscheiden des Propheten die Dogmen ihres Glaubens von den Ahl al-Bayt (Angehörige des Hauses Man darf das Thema Kalifat als den Schwerpunkt aller anderen Diskrepanzen der Glaubensauffassungen der sunnitischen und schiitischen Gelehrten betrachten. / The Arabic word "Khalifa" in the meaning "deputy" or "successor" has been used in the Coran, the holy book of the Muslims at two locations: sura 7, verse 69 and sura 38, verse 26. In These verses is the human being known as God''s representative on earth. In historical context, the term arises after the death of Prophet Muhammad in 632. The first four successors of him in the political leadership of the community calls in the Sunni historiography as the "Rashidun" means (the rightly guided). During this time, i. e. from 632 to 661, the term "Amir al-Mu''minin" (Commander of the Faithful) was created as the title for the Caliphs; thereby the rulers were also addressed. The question of the succession of the Prophet Muhammad became a fundamental point of conflicts within the young Muslim community. From these contentions arose then the confessional division of the Muslim world in the Sunni majority and the Shia minority. Basically, there are similarities and differences between the two mainstreams of the Islamic community, the Sunnis and Shiites. The dimensions of disagreements between Sunnis and Shiites are more than their similarities, although these differences at first glance are not recognizable. The roots of all these differences are due to the fact that the Shiites after the passing away of the Prophet adopted the dogmas of their faith from the Ahl al-Bayt (solely 13 members of the house of the Prophet) and the Sunnis from others. It must be considered, that the issue Caliphate is the focus of all other discrepancies in the beliefs of the Sunni and Shiite scholars.

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In der vorliegenden Dissertation wurde ein datengetriebenes Verfahren zum maschinellen Lernen von Mensch-Roboter Interaktionen auf Basis von Mensch-Mensch Demonstrationen entwickelt. Während einer Trainingsphase werden Bewegungen zweier Interakteure mittels Motion Capture erfasst und in einem Zwei-Personen Interaktionsmodell gelernt. Zur Laufzeit wird das Modell sowohl zur Erkennung von Bewegungen des menschlichen Interaktionspartners als auch zur Generierung angepasster Roboterbewegungen eingesetzt. Die Leistungsfähigkeit des Ansatzes wird in drei komplexen Anwendungen evaluiert, die jeweils kontinuierliche Bewegungskoordination zwischen Mensch und Roboter erfordern. Das Ergebnis der Dissertation ist ein Lernverfahren, das intuitive, zielgerichtete und sichere Kollaboration mit Robotern ermöglicht.

Hippocampal place-cell sequences observed during awake immobility often represent previous experience, suggesting a role in memory processes. However, recent reports of goals being overrepresented in sequential activity suggest a role in short-term planning, although a detailed understanding of the origins of hippocampal sequential activity and of its functional role is still lacking. In particular, it is unknown which mechanism could support efficient planning by generating place-cell sequences biased toward known goal locations, in an adaptive and constructive fashion. To address these questions, we propose a model of spatial learning and sequence generation as interdependent processes, integrating cortical contextual coding, synaptic plasticity and neuromodulatory mechanisms into a map-based approach. Following goal learning, sequential activity emerges from continuous attractor network dynamics biased by goal memory inputs. We apply Bayesian decoding on the resulting spike trains, allowing a direct comparison with experimental data. Simulations show that this model (1) explains the generation of never-experienced sequence trajectories in familiar environments, without requiring virtual self-motion signals, (2) accounts for the bias in place-cell sequences toward goal locations, (3) highlights their utility in flexible route planning, and (4) provides specific testable predictions.

Bone healing involves a variety of different cell types and biological processes. Although certain key molecules have been identified, the molecular interactions of the healing progress are not completely understood. Moreover, a clinical routine for predicting the quality of bone healing after a fracture in an early phase is missing. This is mainly due to a lack of techniques to comprehensively screen for cytokines, growth factors and metabolites at their local site of action. Since all soluble molecules of interest are present in the fracture hematoma, its in-depth assessment could reveal potential markers for the monitoring of bone healing. Here, we describe an approach for sampling and quantification of cytokines and metabolites by using microdialysis, combined with solid phase extractions of proteins from wound fluids. By using a control group with an isolated soft tissue wound, we could reveal several bone defect-specific molecular features. In bone defect dialysates the neutrophil chemoattractants CXCL1, CXCL2 and CXCL3 were quantified with either a higher or earlier response compared to dialysate from soft tissue wound. Moreover, by analyzing downstream adaptions of the cells on protein level and focusing on early immune response, several proteins involved in the immune cell migration and activity could be identified to be specific for the bone defect group, e.g. immune modulators, proteases and their corresponding inhibitors. Additionally, the metabolite screening revealed different profiles between the bone defect group and the control group. In summary, we identified potential biomarkers to indicate imbalanced healing progress on all levels of analysis.

Psychological safety is a key factor for successful teamwork. Psychological safety signifies that individuals who work together share the belief that their team is safe for interpersonal risk taking. Since the 1970s, researchers have emphasized the importance of psychological safety for work teams in order to deal with changes and related feelings of uncertainty due to a competition-oriented and fast-paced labor market. Numerous studies demonstrated the relevance of psychological safety for learning from failures and for the improvement of performance levels in all kinds of work contexts. Most notably, psychological safety was found to be related to patient safety in clinical contexts. Thus, psychological safety is particularly relevant in team settings where customers or patients depend on the team’s performance, as is the case in hospital teams, care teams, flight crews, and other interdisciplinary team settings. Changes are inherent in the nature of psychological safety. Yet, researchers have just begun to investigate how psychological safety forms and develops over time. First findings on the development are inconsistent and previous research lacks an overall theoretical framework on the effects of time and other group-bounded factors that affect the development of psychological safety. This dissertation contributs to previous research by focusing on dynamics of psychological safety and embedding the hypotheses into a more holistic theoretical framework on team development over time. More precisely, this work builds on the model of group faultlines that considers group diversity, and more specifically subgroup emergence, as one important origin of psychological safety dynamic across teams. Accordingly, team faultlines, defined as hypothetical lines that split a team into subgroups based on multiple attributes, have a negative impact on the formation of psychological safety. Furthermore, this work refers to a theoretical approach, which emphasizes the inclusion of time in team research thereby encouraging researchers to take a more dynamic perspective on team processes by studying the changes and subsequent effects on team outcomes. As teams are sensitive to signals of psychological safety from the very beginning of teamwork, this work focused on the relation between trajectories of team psychological safety change and team performance. In Study 1, I referred to the Leader-Member-Exchange theory and examined differences in team members’ perceptions caused by subgroup dynamics. Accordingly, members who belong to the in-group of the leader benefit from more exchange of resources compared to members of an out-group. I tested the relation of subgroup belonging and psychological safety in the presence of high or low task conflict, as conflicts are critical events that impact psychological safety. I found that team members who were close to the leader in terms of demographic similarity were less affected by high task conflict compared to members who were demographically different from the leader. This study thus identified a boundary condition of psychological safety, namely subgroup belonging, as being similar to the leader buffered the negative effects of task conflict on perceptions of interpersonal risk-taking. Regarding the development of team perceptions of psychological safety, first studies indicated that psychological safety either remains relatively stable, or slightly decreases over time. In Study 2, I therefore focused on the development of psychological safety and antecedents of both the formation and changes over time. I tested for the effects of three well-studied deep level diversity attributes, namely values, team ability, and team personality, and for effects of group faultlines on psychological safety. The results showed that psychological safety decreased over time. Furthermore, teams who had a strong attitude toward teamwork and were characterized by a weak faultline started into the project with high initial levels of psychological safety (as compared to teams with low attitude toward teamwork and strong faultlines). Yet, in teams with high task-specific skills, psychological safety decreased (as compared to teams with low skills), whereas in teams with high team conscientiousness, psychological safety increased over time (as compared to teams with low team conscientiousness). This study demonstrated the relevance of considering temporal dynamics of psychological safety in team research. Further studies should investigate which factors, other than time, predict the negative development. Does it reflect a natural phenomenon in teams, or are there other mechanisms that explain this finding more accurately such as cross-subgroup communication? Furthermore, important conditions for the formation and development of psychological safety were identified that could provide starting points for the design of interventions regarding how and when the development of psychological safety should be supported from leaders or team coaches. As a consequence of the previous results, the focus of the third study was put on team trajectories of psychological safety, more precisely, whether changes of psychological safety affected team variables such as team performance. According to team development theories, the first half of a project is decisive as team members lay the foundation for important changes around midpoint. A constructive discussion and evaluation at midpoint again separated high- from low-performing teams. Thus, besides absolute levels, relative changes should affect team performance. The results support this proposition as changes of psychological safety predicted team effectiveness above and beyond absolute levels. Taken together, this work highlights the effects of subgroup dynamics and time for research on psychological safety. This dissertation is a pioneer work as all three studies provide crucial insights on dynamics of psychological safety opening up implications for practitioners and new avenues for future research.:Acknowledgements 1 Summary (English) 2 Summary (German) 4 List of Contents 7 List of Figures 10 List of Tables 11 1 Psychological Safety in Teams and Organizations 12 1.1 Relevance of the Topic 12 1.2 Research Objectives 13 1.3 Structure of the Dissertation 15 2 Conceptual Clarifications 16 2.1 Psychological Safety in Teams 16 2.2 Definition of Work Teams 17 2.3 Differences Between Psychological Safety and Trust 18 2.4 Measuring Psychological Safety in Teams 19 3 Antecedents, Outcomes, and Boundary Conditions of Team Psychological Safety 24 3.1 Outcomes of Psychological Safety 25 3.2 Antecedents of Psychological Safety 25 3.2.1 Leadership Behavior 26 3.2.2 Relationship Networks 27 3.2.3 Team Characteristics 27 3.2.4 Individual Differences and Perceptions of Organizational Practices 28 3.3 Psychological Safety as Boundary Condition 28 3.4 Evaluation of the Previous Research, Future Directions, and Contributions 29 4 The Current Research 30 4.1 Contributions 30 4.2 Theoretical Framework of the Dissertation 31 4.3 Overview of the Research Program 35 5 Study 1 – About the Buffering Effect of Subgroup Belonging on the Relation Between Task Conflict and Psychological Safety 39 5.1 Introduction 40 5.1.1 Psychological Safety 41 5.1.2 Relationship and Task Conflict in Teams 42 5.1.3 Empirical Findings on Conflict and Psychological Safety 43 5.1.4 Group Faultlines Impact Team Processes 43 5.1.5 Emergence of Subgroups: Leader In-Group and Out-Groups 44 5.1.6 Goals of the Study and Hypotheses 46 5.2 Method 47 5.2.1 Participants 47 5.2.2 Procedure 47 5.2.3 Assessment and Operationalization of the Variables 48 5.3 Results 50 5.3.1 Agreement Between Staff Members 50 5.3.2 Multilevel Model Analyses Predicting Psychological Safety 52 5.3.3 Conflict and Demographic Faultline Strength Predict Psychological Safety 54 5.3.4 Testing for a Cross-Level Interaction: Belonging to the Principal In-Group or Out-Group as Moderator 54 5.4 Discussion 55 5.4.1 Practical Implications 58 5.4.2 Conclusions 58 6 Study 2 – About the Effects of Time, Demographic Faultline Strength, and Deep–Level Group Diversity on the Development of Psychological Safety 59 6.1 Introduction 60 6.1.1 Psychological Safety in Groups – Definition, Important Outcomes, and Antecedents 62 6.1.2 Hypotheses Development – Theoretical Considerations and Empirical Findings 62 6.1.2.1 The Effect of Time on Group Psychological Safety. 63 6.1.2.2 Demographic Faultline Strength Predicts Initial Levels of Group Psychological Safety. 64 6.1.2.3 Deep Level Group Diversity Predict Initial Levels and Changes of Group Psychological Safety. 66 6.1.2.4 Psychological Safety is Related to Group Performance. 69 6.2 Method 70 6.2.1 Participants 70 6.2.2 Team Task and Recruitment of Participants 71 6.2.3 Design and Procedure 71 6.2.4 Measures 72 6.3 Results 74 6.3.1 Data Preparation, Agreement Between Group Members and Data Aggregation 75 6.3.2 Correlations Between Demographic Faultline Strength, Group Diversity Variables, Psychological Safety, and Group Performance 77 6.3.3 Reasoning of Control Variables for the Linear Growth Curve Model 79 6.3.4 Modelling the Effects of Time and Group Diversity on Group Psychological Safety 80 6.3.4 Fitting the Model’s Structure 80 6.3.5 Effects of Time, Demographic Faultline Strength, and Deep Level Group Diversity on Initial Levels and Changes of Group Psychological Safety 82 6.3.6 Replication of the Positive Relation Between Psychological Safety and Group Performance 83 6.3 Discussion 83 6.4.1 Limitations and Future Research 87 6.4.2 Implications 88 6.4.3 Conclusion 89 7 Study 3 – About the Effects of Relative Changes of Psychological Safety over Time on Team Performance 90 7.1 Introduction 91 7.1.1 Psychological Safety in Teams 92 7.1.2 Initial Levels and Changes of Team Psychological Safety Predict Team Performance 93 7.2 Method 97 7.2.1 Participants 97 7.2.2 Team Task and Recruitment of Participants 98 7.2.3 Design and Procedure 98 7.2.4 Measures 100 7.3 Results 101 7.3.1 Agreement Between Team Members and Data Aggregation 101 7.3.2 Clustering Changes of Psychological Safety Within Teams 101 7.3.3 Correlations Between Psychological Safety Trajectory Clusters and Team Performance 102 7.3.4 Initial Levels and Changes of Psychological Safety Predict Team Performance 105 7.4 Discussion 105 7.4.1 Limitations and Future Research 108 7.4.2 Practical Implications 109 7.4.3 Conclusion 110 8 General Discussion 111 8.1 Summary and Integration of Findings 111 8.2 Theoretical Implications 115 8.3 Strength and Limitations 117 8.4 Future Directions 120 8.5 Practical Implications 123 8.6 Conclusion 126 9 Appendix – R-Script for Cluster-Calculation 128 10 Reference List 130 11 Curriculum Vitae 143 12 Scientific Career 146 13 Eidesstattliche Erklärung 149 / Psychologische Sicherheit ist ein Schlüsselfaktor für erfolgreiche Teamarbeit. Psychologische Sicherheit bedeutet, dass Personen, die zusammenarbeiten, den Glauben teilen, dass das Team sicher ist, um interpersonelle Risiken einzugehen. Seit Mitte der 70er Jahre betonen Forscher die Bedeutung von psychologischer Sicherheit für Arbeitsteams und deren Umgang mit den Veränderungen und der damit verbundenen Unsicherheit verursacht durch einen wettbewerbsorientierten und schnelllebigen Arbeitsmarkt. Zahlreiche Studien zeigen die Relevanz von psychologischer Sicherheit für das Lernen aus Misserfolgen und die Verbesserung der Teamleistung in verschiedenen Arbeitskontexten auf. Ein Befund zeigt, dass psychologische Sicherheit mit der physiologischen Sicherheit von Patienten assoziiert ist. Folglich ist psychologische Sicherheit insbesondere dann von Bedeutung, wenn Patienten oder Klienten von der Leistung eines Teams abhängig sind, wie das bspw. in OP-Teams, Pflegeteams, Flugbesatzung, oder anderen interdisziplinären Settings der Fall ist. Obgleich psychologische Sicherheit auf Gruppenebene konzeptualisiert ist und Veränderungen in der Natur dieses Konstruktes liegen, haben Forscher erst vor Kurzem begonnen zu untersuchen, wie psychologische Sicherheit entsteht und sich im Verlauf der Zusammenarbeit verändert. Jedoch sind die Befunde inkonsistent und der Forschung fehlt ein konzeptuelles Rahmenmodell darüber, wie die Zeit und andere durch die Gruppe bedingte Faktoren die Entwicklung von psychologischer Sicherheit beeinflussen. Diese Dissertation trägt zur vorherigen Forschung bei, indem sie den Fokus auf die Dynamiken psychologischer Sicherheit legt und die Forschungsthesen in ein ganzheitliches theoretisches Rahmenmodell zur Entwicklung von Teams einbettet. Im Einzelnen stützt sich die Arbeit auf das Modell der Gruppenbruchlinien, das Gruppendiversität als eine wichtige Ursache für dynamische Prozesse in Teams aufgrund von Subgruppenbildung ansieht. Demnach haben Gruppenbruchlinien (Faultlines), sogenannte hypothetische Linien, die Teams in homogene Subgruppen anhand multipler Attribute teilen, negative Folgen auf die Entstehung von psychologischer Sicherheit. Weiterhin bezieht sich die Arbeit auf einen theoretischen Ansatz, der den Einbezug der Zeit in den Vordergrund rückt und Forscher ermutigen soll eine dynamischere Perspektive auf Teamprozesse einzunehmen und Veränderungen sowie deren Folgen für Teamarbeit zu studieren. Da Teams von Beginn an und in den frühen Phasen der Zusammenarbeit für Signale psychologischer Sicherheit empfänglich sind, lag der Fokus auf Veränderungen in der psychologischen Sicherheit und dem Zusammenhang zwischen Veränderungen und Teamleistung. In Studie 1 bezog ich mich auf die Leader-Member-Exchange Theorie und untersuchte Unterschiede in der Wahrnehmung von psychologischer Sicherheit von Teammitgliedern aufgrund von Subgruppendynamik. Demnach profitieren In-Group Mitglieder der Führungskraft von einem höheren Austausch von Ressourcen im Vergleich zu Mitgliedern der Out-Group. Ich testete die Beziehung von Subgruppenzugehörigkeit und psychologischer Sicherheit in der Präsenz von hohem vs. niedrigem Aufgabenkonflikt, da Konflikte kritische Ereignisse sind, die sich negativ auf die psychologische Sicherheit auswirken können. Ich fand heraus, dass Teammitglieder, die mit ihrer Führungskraft demographisch ähnlich waren, von den negativen Auswirkungen von Aufgabenkonflikt weniger betroffen waren als Teammitglieder, die sich von der Führungskraft diesbezüglich unterschieden. Diese Studie identifiziert eine Grenzbedingung für psychologische Sicherheit, nämlich die Subgruppenzugehörigkeit, da die demographische Nähe zur Führungskraft den negativen Effekt von Aufgabenkonflikt für die Wahrnehmung von psychologischer Sicherheit pufferte. Hinsichtlich der Entwicklung von psychologischer Sicherheit, legen erste Studien nahe, dass sie sich nicht verändert, bzw. Über die Zeit leicht abnimmt. In Studie 2 untersuchte ich daher die Entwicklung von psychologischer Sicherheit und Antezedenzien für die Entstehung und Veränderungen im Verlauf der Zeit. Ich testete für Effekte von drei gut erforschten tieferliegenden Diversitätsattributen, nämlich Werte, Teamfähigkeit und Teampersönlichkeit. Die Ergebnisse zeigen, dass psychologischer Sicherheit über die Zeit abnahm. Darüber hinaus starteten Teams, die eine positive Einstellung zu Teamarbeit hatten und deren Gruppe von schwachen Faultlines gekennzeichnet war, mit einem hohen Anfangsniveau an psychologischer Sicherheit in die Projektarbeit (im Vergleich zu Teams mit negativer Einstellung zur Teamarbeit und starker Faultline). Allerdings nahm die psychologische Sicherheit in Teams mit hohen aufgabenspezifischen Fähigkeiten (im Vergleich zu niedrigen aufgabenspezifischen Fähigkeiten) über die Zeit ab, wohingegen sie in Gruppen mit hoher Gewissenhaftigkeit (im Vergleich zu niedriger Gewissenhaftigkeit) zunahm. Die Studie zeigt die Relevanz der Berücksichtigung von zeitlichen Dynamiken der psychologischen Sicherheit in der Team Forschung. So kann weiterführend dazu geforscht werden, welche anderen Faktoren als Zeit die negative Entwicklung vorhersagen. Handelt es sich hierbei um eine natürliche Entwicklung in Teams, oder erklären andere Mechanismen wie bspw. Kommunikation über Subgruppen hinweg diesen Befund? Darüber hinaus wurden wichtige Konditionen für die Entstehung und Entwicklung von psychologischer Sicherheit identifiziert, die zur Planung von Inhalten und dem Timing von Teaminterventionen zur Förderung der psychologischen Sicherheit durch Führungskräfte oder Team Coaches genutzt werden können. Als Konsequenz der vorherigen Ergebnisse, lag der Fokus der dritten Studie auf den Teamverläufen von psychologischer Sicherheit, präziser noch, auf den Effekten von Veränderungen psychologischer Sicherheit und deren Auswirkungen auf andere Teamvariablen wie bspw. Teamleistung. Laut Team Entwicklungstheorien ist die erste Hälfte der Projektarbeit entscheidend da Teammitglieder die Fundamente für bedeutende Veränderungen zur Mitte legen. Eine konstruktive Diskussion und Bewertung zur Mitte des Projektes wiederum trennt Hochleistungsteams von Teams mit schwacher Leistung. Daher sollte neben der absoluten Einschätzung von psychologischer Sicherheit auch die relative Veränderung Auswirkungen auf die Teamleistung haben. Die Ergebnisse unterstützen diese Annahme. Wir fanden dass Veränderungen in der psychologischen Sicherheit die Teameffektivität über die Baseline hinaus vorhersagten. Insgesamt hebt diese Arbeit die Effekte von Subgruppendynamiken und Zeit für die Forschung von psychologischer Sicherheit hervor. Diese Dissertation leistete Pionierarbeit indem alle drei Studien entscheidende Einsichten in die Dynamiken von psychologischer Sicherheit bieten und Implikationen für Praktiker beinhalten sowie neue Bereiche für zukünftige Forschung eröffnen.:Acknowledgements 1 Summary (English) 2 Summary (German) 4 List of Contents 7 List of Figures 10 List of Tables 11 1 Psychological Safety in Teams and Organizations 12 1.1 Relevance of the Topic 12 1.2 Research Objectives 13 1.3 Structure of the Dissertation 15 2 Conceptual Clarifications 16 2.1 Psychological Safety in Teams 16 2.2 Definition of Work Teams 17 2.3 Differences Between Psychological Safety and Trust 18 2.4 Measuring Psychological Safety in Teams 19 3 Antecedents, Outcomes, and Boundary Conditions of Team Psychological Safety 24 3.1 Outcomes of Psychological Safety 25 3.2 Antecedents of Psychological Safety 25 3.2.1 Leadership Behavior 26 3.2.2 Relationship Networks 27 3.2.3 Team Characteristics 27 3.2.4 Individual Differences and Perceptions of Organizational Practices 28 3.3 Psychological Safety as Boundary Condition 28 3.4 Evaluation of the Previous Research, Future Directions, and Contributions 29 4 The Current Research 30 4.1 Contributions 30 4.2 Theoretical Framework of the Dissertation 31 4.3 Overview of the Research Program 35 5 Study 1 – About the Buffering Effect of Subgroup Belonging on the Relation Between Task Conflict and Psychological Safety 39 5.1 Introduction 40 5.1.1 Psychological Safety 41 5.1.2 Relationship and Task Conflict in Teams 42 5.1.3 Empirical Findings on Conflict and Psychological Safety 43 5.1.4 Group Faultlines Impact Team Processes 43 5.1.5 Emergence of Subgroups: Leader In-Group and Out-Groups 44 5.1.6 Goals of the Study and Hypotheses 46 5.2 Method 47 5.2.1 Participants 47 5.2.2 Procedure 47 5.2.3 Assessment and Operationalization of the Variables 48 5.3 Results 50 5.3.1 Agreement Between Staff Members 50 5.3.2 Multilevel Model Analyses Predicting Psychological Safety 52 5.3.3 Conflict and Demographic Faultline Strength Predict Psychological Safety 54 5.3.4 Testing for a Cross-Level Interaction: Belonging to the Principal In-Group or Out-Group as Moderator 54 5.4 Discussion 55 5.4.1 Practical Implications 58 5.4.2 Conclusions 58 6 Study 2 – About the Effects of Time, Demographic Faultline Strength, and Deep–Level Group Diversity on the Development of Psychological Safety 59 6.1 Introduction 60 6.1.1 Psychological Safety in Groups – Definition, Important Outcomes, and Antecedents 62 6.1.2 Hypotheses Development – Theoretical Considerations and Empirical Findings 62 6.1.2.1 The Effect of Time on Group Psychological Safety. 63 6.1.2.2 Demographic Faultline Strength Predicts Initial Levels of Group Psychological Safety. 64 6.1.2.3 Deep Level Group Diversity Predict Initial Levels and Changes of Group Psychological Safety. 66 6.1.2.4 Psychological Safety is Related to Group Performance. 69 6.2 Method 70 6.2.1 Participants 70 6.2.2 Team Task and Recruitment of Participants 71 6.2.3 Design and Procedure 71 6.2.4 Measures 72 6.3 Results 74 6.3.1 Data Preparation, Agreement Between Group Members and Data Aggregation 75 6.3.2 Correlations Between Demographic Faultline Strength, Group Diversity Variables, Psychological Safety, and Group Performance 77 6.3.3 Reasoning of Control Variables for the Linear Growth Curve Model 79 6.3.4 Modelling the Effects of Time and Group Diversity on Group Psychological Safety 80 6.3.4 Fitting the Model’s Structure 80 6.3.5 Effects of Time, Demographic Faultline Strength, and Deep Level Group Diversity on Initial Levels and Changes of Group Psychological Safety 82 6.3.6 Replication of the Positive Relation Between Psychological Safety and Group Performance 83 6.3 Discussion 83 6.4.1 Limitations and Future Research 87 6.4.2 Implications 88 6.4.3 Conclusion 89 7 Study 3 – About the Effects of Relative Changes of Psychological Safety over Time on Team Performance 90 7.1 Introduction 91 7.1.1 Psychological Safety in Teams 92 7.1.2 Initial Levels and Changes of Team Psychological Safety Predict Team Performance 93 7.2 Method 97 7.2.1 Participants 97 7.2.2 Team Task and Recruitment of Participants 98 7.2.3 Design and Procedure 98 7.2.4 Measures 100 7.3 Results 101 7.3.1 Agreement Between Team Members and Data Aggregation 101 7.3.2 Clustering Changes of Psychological Safety Within Teams 101 7.3.3 Correlations Between Psychological Safety Trajectory Clusters and Team Performance 102 7.3.4 Initial Levels and Changes of Psychological Safety Predict Team Performance 105 7.4 Discussion 105 7.4.1 Limitations and Future Research 108 7.4.2 Practical Implications 109 7.4.3 Conclusion 110 8 General Discussion 111 8.1 Summary and Integration of Findings 111 8.2 Theoretical Implications 115 8.3 Strength and Limitations 117 8.4 Future Directions 120 8.5 Practical Implications 123 8.6 Conclusion 126 9 Appendix – R-Script for Cluster-Calculation 128 10 Reference List 130 11 Curriculum Vitae 143 12 Scientific Career 146 13 Eidesstattliche Erklärung 149