LOW DIGITAL FINGER RATIO: AN INDICATOR OF MENTAL TOUGHNESS AND PRENATAL PROGRAMMING OF SPORTING SUCCESS

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1 LOW DIGITAL FINGER RATIO: AN INDICATOR OF MENTAL TOUGHNESS AND PRENATAL PROGRAMMING OF SPORTING SUCCESS Dr. Arvind Malik Associate Professor,Department of Physical Education, Kurukshetra University, Haryana, India. ABSTRACT The ratio between length of the 2nd (the index finger) and 4th (the ring finger) digit (2D:4D) is positively correlated with prenatal exposure to estrogen, negatively correlated to prenatal exposure to testosterone and traits beneficial sport performance. The purpose of this study was to explore the relationships between digital finger ratio (2d:4d) and mental toughness with sporting achievement. Participants includes 268 (male = 157 and females =111) sports people of years from different universities of Haryana, India, Vernier Caliper was used to measure digit ratio of both hands and mental was assessed with Alternative Psychological Performance Inventory (PPI-A, Golby et al., 2007) and Sport Mental Toughness Questionnaire (SMTQ, Sheard et al., 2009). A significant difference (p= 0.01) for 2d:4d was found between the high and low sports achievement groups. Group with low 2d:4d differ significantly (p=0.001) on all sub scale of mental toughness and sports mental toughness then high 2d:4d group. Specifically, this difference was significant when comparing the highest (National /AIU) and lowest (state/university) groups. Perhaps there is a threshold for prenatal testosterone s influence upon sporting ability. It is proposed that high prenatal levels of testosterone may contribute to the development of increased mental toughness required for sporting success. Key words: Digit ratio, sports achievement, mental toughness, testosterone. INTRODUCTION: The ratio of the second to the fourth finger length on the right hand (2D:4D, or digit ratio) is putatively a marker of the organizational effect of prenatal testosterone in humans Manning at el. (1998), Breedlove (2010), McIntyre (2006), Honekopp and Watson (2010). It is sexually dimorphic, with women having higher ratios than men on average. It has been hypothesized that 2D:4D reflects prenatal androgen levels and the individual s sensitivity to androgens Breedlove On-Line International Blind Peer Reviewed Indexed Journal 43

2 (2010). There is indirect evidence that supports such hypothesis in humans. Higher (more feminized) 2D:4D ratios were reported in females with androgen insensitivity syndrome Berenbaum at el. (2009). Individuals with congenital adrenal hyperplasia (CAH), a condition associated with high levels of prenatal androgens, have been found to have smaller 2D:4D ratio. Because finger length and the differentiation of the urinogenital tract are both controlled by the Homeobox genes Hox a and d, 2D:4D is thought to be a somatic marker of prenatal sex hormone exposure (Kondo et al. 1997). Indeed, Lutchmaya and Manning (2004) have shown that high levels of fetal sex hormones derived from samples of amniotic fluid are correlated with 2D:4D at age two, with low 2D:4D associated with high fetal testosterone relative to fetal estradiol. Testosterone influences the growth of the ring finger (4D), whereas oestrogen exposure stimulates the growth of the index finger (2D) (Manning, 2002). Specifically, males demonstrated a lower ratio, arguably due to increased prenatal testosterone exposure (Manning, 2002). Initial research exploring the biological basis of behavior has identified the organizational effects of prenatal testosterone on various adult psycho-physiological parameters (Neave et al., 2003). Success in sport is proposed to be determined by marginal psycho-physiological differences. Research has recently considered the influence of biological factors on developing psychological constructs, i.e. (Golby and Sheard, 2006). It is suggested that high levels of prenatal testosterone may have a permanent masculinizing effect on human behavior, (Manning, 2002) which could potentially explain the relationship between sporting performance and 2D:4D (Honekopp et al., 2006). Masculine attributes arguably play an important role in sport performance, e.g., aggression. Sports performance has been found to negatively relate to 2D:4D in sports such as football, athletics, skiing, fencing, cross country running and general fitness (Manning, 2002; Honekopp et al., 2006, Manning & Hill, 2009, Bennett et al.,2010, Longman et al., 2011, Giffin NA et al., 2012). It appears that those exposed to increased levels of prenatal testosterone have greater sporting ability. This link between digit ratio and sport performance is thought to be multidimensional. Significant associations have been widely noted between physiological parameters (e.g., effective cardiovascular system, physical fitness and visuo-spatial On-Line International Blind Peer Reviewed Indexed Journal 44

3 ability) and 2D:4D. Behavioral differences such as increased exercise frequency have been identified in those with low 2D:4D in comparison with high digit ratio (Honekopp et al., 2006). One particular construct that may be deemed important in differentiating athletes performance is mental toughness (Kuan and Roy, 2007; Golby and Sheard, 2004). The ability to regulate emotion and imagery effectively, display commitment and determination, possess an uncontrollable desire to succeed, and an unshakeable confidence, are all characteristic of mentally tough individuals (Crust and Clough, 2005). A further feature of mental toughness is the ability to adapt to stressful conditions. Dealing successfully with competitive stressors requires effective coping strategies. Individuals tend to have a preferred coping style that can be defined as the individual s tendency to respond and resolve problems with a particular style of action (Bolger, 1990). This study was designed to examine the potential of varying levels of prenatal testosterone to differentiate individuals levels of mental toughness on four sub scale self-belief, determination, positive cognition and visualization, which are considered to be important prerequisites of sporting excellence. METHODS: Participants- The participants in this study were 268 (male = 157 and females =111) sports people of years from different universities of Haryana, India, who had won position at All India Interuniversity /National level (N=79), represented University/State(N=92) and State/University participation(n=97). Participants included competitors from a range of sports, including volleyball, hockey, boxing, judo, archery and shooting. Measures- Mental toughness: The Alternative Psychological Performance Inventory (PPI-A, Golby et al., 2007) was used to measure mental toughness. The questionnaire obtains four sub scale scores: self-belief, determination, positive cognition and visualization. Responses are given on a five point Likert scale, which ranges from almost always to almost never. Collectively satisfying absolute and incremental fit index benchmarks, the inventory possesses satisfactory psychometric properties, with adequate reliability and convergent and discriminant validity On-Line International Blind Peer Reviewed Indexed Journal 45

4 (Golby et al., 2007). Sport Mental Toughness Questionnaire: (SMTQ, Sheard et al., 2009) was used as a secondary measure of mental toughness. The questionnaire yields a total mental toughness figure, and 3 subscale scores: confidence, constancy and control. There is preliminary support for the factor structure, reliability and validity of the measure (Sheard et al., 2009). RESULTS: Mean right hand digital finger ratio (2d:4d) of all the three groups were 0.943, and 0.978, which differ significantly as F (1, 297) = 6.78, p< Similarly mean left hand digital finger ratio (2d:4d) of all the three groups were 0.945, and 0.980, which also differ significantly as F (1, 297) = 8.96, p< Table 1 Means (±standard deviation) 2d:4d of different groups and ANOVA analysis Variables Group 1 Group 2 Group 3 F Value Level of Significance Right hand 0.943(0.09) (0.04) (0.19) digit ratio Left hand digit ratio (0.19) (0.03) (0.21) Group 1 = Position holder at All India Interuniversity /National level Group 2 = University/State representation. Group 3 = State/University participation. Means, standard deviations and ANOVA analysis of all the four measures of Psychological Performance Inventory (PPI) for groups having 2d:4d less then and more then are presented in Table 1. A significant group difference was found in all the measures of psychological performance inventory for mental toughness as Self Belief F (1, 207) = 18.36, p < 0.001, Determination F (1, 207) = 12.71, p < 0.001, Positive Cognition F (1, 207) = 28.52, p < and Visualization F (1, 207) = 12.69, p < Table - 1 On-Line International Blind Peer Reviewed Indexed Journal 46

5 Means (±standard deviation) of all variables for Psychological Performance Inventory and ANOVA analysis Variable Mean (SD) of 2d:4d less then Mean (SD) of 2d:4d more then F Value Level of Significance Right hand Left Right hand Left hand hand Self Belief (2.71) (2.84) (2.39) (3.07) Determination (1.99) (2.69) (1.84) (2.81) Positive (2.45) (2.38) Cognition (2.87) (2.04) Visualization (2.14) (3.04) (2.69) (3.11) Means, standard deviations and ANOVA analysis of all the three measures of Sport Mental Toughness Questionnaire (SMTQ) for groups having 2d:4d less then and more then are presented in Table 2. A significant group difference was found in all the measures of sports mental toughness as Confidence F (1, 207) = 9.31, p < 0.01, Consistency F (1, 207) = 7.52, p < 0.01 and Control F (1, 207) = 19.98, p < Table - 2 Means (±standard deviation) of all variables Sport Mental Toughness Questionnaire and ANOVA analysis Variable Mean (SD) of 2d:4d Mean (SD) of 2d:4d F Level of less then more then Value Significance Right hand Left Right hand Left hand hand Confidence (3.52) (2.64) On-Line International Blind Peer Reviewed Indexed Journal 47

6 (3.14) (2.25) Constancy (2.28) (2.01) (2.52) (2.42) Control (2.07) (2.01) 9.53 (2.03) (2.26) DISCUSSION OF RESULTS: A significant difference p<0.01 was found between digital finger ratio of high performer group and low performer sports groups, which substantiate previous research; those exposed to high prenatal testosterone possess greater aptitude within sport (Honekopp et al., 2006; Manning, 2002; Manning and Taylor, 2001; Voracek et al., 2010). This difference was significant when comparing the highest (international/national) and lowest (state /university) groups; perhaps there is a threshold for prenatal testosterone s influence upon sporting ability. This finding extends previous research which merely identified a negative relationship between highest sport achievement level and digit ratio (Honekopp et al., 2006, Longman et al., 2011 and Giffin NA et al., 2012). Future research may wish to explore the variances in digit ratio between differing competitive levels further. The psychological differences identified among performers, competing at different sporting levels in this study, may illuminate the nature of this relationship. Research has provided strong evidence for the claim that greater self confidence is associated with an increased perception of influence over one s life outcomes (Moritz et al., 2000).This sense of empowerment, coupled with increased positive cognition, could relate to higher levels of emotional stability (Gucciardi et al., 2008). This would indicate less use of emotion focused strategies, which is characteristic of the mentally tough person (Nicholls et al., 2008). Findings of the present study also show that those people who compete at an international/national standard and with low 2D:4D scored significantly higher on the subcomponents of determination (SMTQ) and visualization (SMTQ) than those competing at all lower levels and with high 2D:4D. Perhaps those competing at an elite level are likely to be exposed to visualization and imagery techniques more frequently than their non-elite counterparts (MacIntyre and Moran, On-Line International Blind Peer Reviewed Indexed Journal 48

7 2007). They may possess greater determination, because of the enhanced work ethic necessary to succeed (Holland et al., 2010). Significant differences were identified in relation to all measured mental toughness subcomponents. Specifically, those competing at higher levels (international/ national), and with low 2D:4D, scored higher on the subscales of self-belief (SMTQ), determination (SMTQ), positive cognition (SMTQ), visualization (SMTQ), confidence (PPI), control (PPI), constancy (PPI) than those with high 2D:4D and competing at lower levels(state/university). This provides further support for the claim that these characteristics are important in sport performance (Crust, 2008; Golby and Sheard, 2004; Gucciardi et al., 2008, Jimm and Jennifer, 2011) and also highlights the potential of prenatal testosterone in partially explaining their development. However, it is important to consider the possibility that the present results could be due to a remarkable coincidence, and further evidence is necessary before firm conclusions can be drawn. CONCLUSION: The present paper provides preliminary support for an association between prenatal testosterone levels and mental toughness required for the success in sports. Findings tentatively advocate that the revealed psychological characteristics may be moderately biologically predetermined. References: Bennett, M. Manning, JT. Cook, CJ. Kilduff, LP. (2010). Digit ratio (2D:4D) and performance in elite ugby players. Journal of Sports Sciences. 28(13), Breedlove SM (2010). Minireview: Organizational hypothesis: instances of the fingerpost. Endocrinology 151: Berenbaum SA, Bryk KK, Nowak N, Quigley CA, Moffat S (2009) Fingers as a Marker of Prenatal Androgen Exposure. Endocrinology 150: Bolger, N. (1990). Coping as a personality process. Journal of Personality and Social Psychology 59, Crust, L. and Clough, P.J. (2005) Relationship between mental toughness and physical endurance. Perceptual and Motor Skills 100, On-Line International Blind Peer Reviewed Indexed Journal 49

8 Crust, L. (2008). A review and conceptual re-examination of mental toughness: Implications for future researchers. Elsevier, Personality and Individual Differences 45, Giffin, NA., Kennedy, RM., Jones, ME., Barber, CA.,(2012). Varsity athletes have lower 2D:4D ratios than other university students. Journal of Sports Sciences 30(2): Golby, J. and Sheard, M. (2004). Mental toughness and hardiness at different levels of rugby league. Elsevier: Personality and Individual Differences 37, Golby, J. and Sheard, M. (2006). The relationship between genotype and positive psychological development in National-level swimmers. European Psychologist 11(2), Golby, J., Sheard, M. and Van Wersch, A. (2007).Evaluating the Factor Structure of the Psychological Performance Inventory. Perceptual and Motor Skills 105, Gucciardi, D., Gordon, S. and Dimmock, J. (2008). Towards an understanding of mental toughness in Australian football. Journal of Applied Sport Psychology 20, Honekopp, J., Manning, J.T. and Muller, C. (2006). Digit ratio (2D:4D) and physical fitness in males and females: Evidence for effects of prenatal androgens on sexually selected traits. Elsevier, Hormones and Behaviour 49, Honekopp J, Watson S (2010). Meta-Analysis of Digit Ratio 2D:4D Shows Greater Sex Difference in the Right Hand. American Journal of Human Biology 22: Holland, M. J. G., Woodcock, C., Cumming, J. and Duda, J. L. (2010). Mental qualities and employed mental techniques of young elite team sport athletes. Journal of Clinical Sport Psychology 4, Jimm, G., Jennifer, M., (2011). Exploring the organizational effect of prenatal testosterone upon the sporting brain. Journal of Sports Science and Medicine 10, Kuan, G. and Jolly, R. (2007) Goal profiles, mental toughness and its influence on performance outcomes among Wushu athletes. Journal of Sports Science 6, Kondo, T. Zakany, J. Innis, J. Duboule, D. (1997). Of fingers, toes and penises. Nature 7,390:29. Longman, D. Stock, JT. Wells, JC. (2011). Digit ratio (2D:4D) and rowing ergometer performance in males and females. Am. J. Phys. Anthropol. 144(3), On-Line International Blind Peer Reviewed Indexed Journal 50

9 Lutchmaya S, Baron-Cohen S, Raggatt P, Knickmeyer R, Manning JT (2004) 2nd to 4th digit ratios, fetal testosterone and estradiol. Early Human Development 77: Manning JT, Scutt D, Wilson J, Lewis-Jones DI (1998). The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. Human Reproduction 13: Manning, J.T. (2002). Digit ratio: a pointer to fertility, behaviour and health. Rutgers University Press. Manning, JT. Hill, MR. (2009). Digit ratio (2D:4D) and sprinting speed in boys.american journal of Human Biology.. 21(2), Manning, JT. Taylor, RP. (2001). Second to fourth digit ratio and male ability in sport: implications for sexual selection in humans. Evolution and Human Behavior 22, Moritz, S.E., Feltz, D.L., Fahrbach, K.R. and Mack, D.E. (2000). The relation of selfefficacy measures to sport performance: A meta-analytic review. Research Quarterly for Exercise and Sport 71, MacIntyre, T.E. and Moran, A.P. (2007). A qualitative investigation of imagery use and meta-imagery processes among the canoe slalom competitors. Journal of Imagery Research in Sport and Physical Activity 2, McIntyre MH (2006). The use of digit ratios as markers for perinatal androgen action. Reproductive Biology and Endocrinology 4: 10. Neave, N., Laing, S., Fink, B. and Manning, J. T. (2003). Second to fourth digit ratio, testosterone and perceived male dominance. The Royal Society 270, Nicholls, A.R., Polman, R.C.J., Levy, A.R. and Backhouse, S.H. (2008). Mental toughness, optimism, pessimism, and coping among athletes. Elsevier, Personality and Individual Differences 44 (1) Sheard, M., Golby, J. and Van-Wersch, A. (2009). Progress toward construct validation of the Sports Mental Toughness Questionnaire(SMTQ). European Journal of Psychological Assessment Golby and Meggs (3), Voracek, M., Reimer, B. and Dressler, G. (2010). Digit ratio (2D:4D) predicts sporting success among female fencers independent from physical, experience, and personality factors. Scandinavian Journal of Medicine & Science in Sports 20 (6), On-Line International Blind Peer Reviewed Indexed Journal 51

Exploring the organizational effect of prenatal testosterone upon the sporting brain

Journal of Sports Science and Medicine (2011) 10, 445-451 http://www.jssm.org Research article Exploring the organizational effect of prenatal testosterone upon the sporting brain Jim Golby and Jennifer