ContentsChapter 1 General Introduction (1)1.1 Research Background (1)1.2 Overview (37)Chapter 2 Study One (39)2.1 Introduction (39)2.2 Methods (43)2.3 Results (49)2.4 Discussion (57)Chapter 3 Study Two (66)3.1 Introduction (66)3.2 Methods (71)3.3 Results (77)3.4 Discussion (81)Chapter 4 Study Three (86)4.1 Introduction (86)4.2 Methods (94)4.3 Results (98)4.4 Discussion (103)Chapter 5 Study Four (112)5.1 Introduction (112)5.2 Methods (120)5.3 Results (125)5.4 Discussion (130)Chapter 6 General Discussion (136)6.1 Recap Main Findings of the Four Studies (136)6.2 Implications (140)6.3 Future Research Directions (141)6.4 Conclusions (143)Bibliography (144)