Mental Toughness 1 Running Head: Mental Toughness The Concept of Mental Toughness: Tests of Dimensionality, Nomological Network and Traitness

1 Objectives: Mental toughness has received increased scholarly attention in recent years, yet 2 conceptual issues related to its (i) dimensionality, (ii) nomological network, and (iii) traitness 3 remain unresolved. The series of studies reported in this paper were designed to examine 4 these three substantive issues across several achievement contexts including sport, education, 5 military and the workplace. Methods: Five studies were conducted to examine these research 6 aims: Study 1: N = 30; Study 2: calibration sample (n = 418), tertiary students (n = 500), 7 athletes (n = 427), and employees (n = 550); Study 3: N = 497 employees; Study 4: N = 203 8 tertiary students; Study 5: N = 115 army candidates. Results: Collectively, the results of these 9 studies revealed that mental toughness may be best conceptualized as a undimensional rather 10 than a multidimensional concept; plays an important role in performance, goal progress, and 11 thriving despite stress; and can vary and have enduring properties across situations and time. 12 Conclusion: This series of studies provides a foundation for further basic and applied 13 research of mental toughness across various achievement contexts. 14 15 16