The Effects of Sex, Education and Handedness on Rosenberg

Moussa Mahamat Boukar¹ and Senol Dane^2*

^*Correspondence: Senol Dane, Department of Physiology, College of Health Sciences, Nile University of Nigeria, Abuja, Nigeria, Email:

Author info »

Introduction

Self-esteem is described as feelings of one’s personal selfworth [1]. It gives us person’s evaluation about his or her own worth. Self-esteem means one ’ s overall subjective emotional evaluation of his or her own worth. It is the decision made by an individual as an attitude towards the self. Also, self-esteem was defined as our thoughts about ourselves, including our positive or negative evaluations [2]. Self-esteem is an important indicator of some characteristics, such as school success [3,4], happiness [5], achievement in marriage and other relationships [6], and criminal behavior [6]. There are many synonyms of selfesteem such as self-worth, self-regard, self-respect and self-integrity.

Testosterone is an important hormone for modulating aggression and self-regulation. It has been reported that acute testosterone changes in men are positively associated with aggressive behavior for those with more independent self-construals, whereas basal testosterone is negatively associated with aggression when individuals have more interdependent self-construals [7]. They suggested that self-construal moderates the association between testosterone and aggression.

Geschwind and Galaburda asserted a claim that elevated levels of fetal testosterone are associated with lefthandedness [8]. In addition to, it has been suggested that adult levels of circulating testosterone might be related to fetal testosterone levels [9], and that anomalous dominance (left-handers, mixed-handers, and righthanders with familial sinistrality) [10] and handedness [11] may be related to levels of circulating testosterone in adult men and women.

A lot of studies on the relationships between cerebral lateralization and neurological and mental health problems have been reported. These are some examples. Patients with schizophrenia has an increased left ear (right temporal hemisphere) advantage and left temporal hemispheric dysfunction [12]. In above mentioned study, they reported increased frequency of mixed-handedness and decreased frequencies of both right- and lefthandedness in comparison with controls in patients with schizophrenia. Also, there was a sex related differences in which the male patients had significantly increased incidences of left eye dominance, crossed hand-eye dominance, and non-congruent hand-eye dominance, but not the female patients [13]. In another study, the higher frequencies of left-handedness, left-eyedness and left nasal dominance were reported in children with autism compared to normal children [14]. In men, the incidence of left-handedness and left-eyedness were higher in patients with migraine than in controls. The presence of aura in patients with migraine was associated with the incidence of left-eyedness and crossed hand-eye dominance for the total sample and women [15]. It has been reported that the heroin and hashish addictions were related with the left-handedness and cigarette, alcohol, heroin and hashish addictions were with the lefteyedness and the crossed hand-eye dominance [16].

However the relationships amongst sex, education level, and some behavioral tests such as alexithymia [17], depression [18] are well known in African university students, there is no study amongst sex, education level, handedness and self-esteem. The behavioral studies need the robust replications with the larger sample size. The present study was planned to investigate the effects of sex, education level, and handedness on self-esteem in Nigerian university students.

Materials and Methods

Subjects

A survey was carried out to assess self-esteem scores. This was to ensure the results obtained from the probing were valid and reliable. In the survey, the questionnaire was posted online for volunteers to fill out. A total of 345 volunteers participated in this survey (168 women, mean age=20.74, SD=0.92; 177 men, mean age=21.12, SD=1.12). They were students of the different faculties in Nile University of Nigeria. Hand preference was assessed on the Edinburgh Handedness Inventory [19]. All subjects completed the study voluntarily.

Exclusion criteria were health problems such as psychiatric, respiratory, metabolic, cardiac, or autonomic nervous system diseases that might change the selfesteem scores. The present study was conducted and its data was collected between October 2018 to February 2019. This study was performed in accordance with the Declaration of Helsinki. All subjects were voluntaries to attend the study. All participants signed informed consents after the aims and objectives of the study have been clearly explained.

Self-esteem

Rosenberg Self-esteem Scale [20] was used to assess the points associated with self-esteem. The reliability and validity of Rosenberg Self-esteem Scale have been welldemonstrated [21,22]. The participants were asked to rate the degree to which they agree with each of the statements using a five-point Likert rating scale that ranges from “strongly agree” to “strongly disagree.” The questionnaire was posted on the following platforms: The school faculty website. Google classroom for students to fill out and social media, every student can fill the questionnaires only once while login into the online survey students ID is required in order to protect duplication.

Statistical analyses

Measured values are given as a mean ± standard deviation. Statistical analysis was performed by using SPSS for Windows (version 18) statistical program. Student’s t-test (independent sample test) and one way ANOVA tests were used to compare the alexithymia scores in university students. p-value less than 0.05 were considered significant.

Results

Of 177 male participants, 156 (88.1%) were righthanded and 21 (11.9%) left-handed; of 168 female participants, 152 (90.5%) were right-handed and 16 (9.5%) left-handed. The gender frequency difference for handedness was not significant. There are no statistical differences in self-esteem score by sex, age, and weight and education level and department.

Left-handed university students had statistically significant higher self-esteem scores compared to righthanded students (t=3.58, p˂0.001) (Table 1).

Table 1: The mean (± SD) self-esteem scores by handedness.

Discussion

It is well known that self-esteem (self-worth or selfrespect) can be an important part of success. Decreased self-esteem in especially young people can cause people to feel defeated or depressed themselves. Also, decreased self-esteem can result in people to reach bad decisions and to catch destructive relationships, or to fail to live up to their full potential. Conversely, increased self-esteem can certainly be off-putting to others and can even damage personal relationships. It has been suggested that testosterone is an important hormone for modulating aggression and self-regulation and selfconstrual moderates the association between testosterone and aggression [7].

Geschwind and Behan [23] and Geschwind and Galaburda [24] proposed that anomalous dominance (left-handedness and both handedness) may be related with the effects of testosterone on the fetal brain; for this reason the left-handed persons have better developed motor, attentional, and spatial functions. It has been well known that the relationships between left-handedness and higher athletic performances and sportive achievements were reported in athletes of both team [25,26] and individual [25,27-31] sports. This relation would be consistent with their proposal. Also, it has been reported that the destructive aggressiveness was higher for the left- than the right-handed athletes and the tolerance and insistence scores were higher for the rightthan the left handed athletes and suggested that higher aggressiveness and less tolerance and insistence in the left-handers may be associated with their higher sports performance [32]. In the present study, the left-handed university students had the higher self-esteem scores than the right handed participants. It can be suggested that these results supports the relationships amongst left-handedness, self-esteem (self-regulation and selfconstrual), the higher sport performance and testosterone.

It has been suggested the ratio of second to fourth digit lengths (2D:4D) as markers for fetal androgens [33]. In men, the fourth digit is longer than the second digit, vice versa in women [34]. It has been reported that lower 2D: 4D among men is associated with higher athletic performance [35], and among women [36]. A recent study reported that the frequency of left handedness was higher in males, but there was no gender difference in eyedness, footedness and digit ratio. Also the digit ratio for the right hand was higher in subjects with crossed hand-eye dominance, while the left hand digit ratio was higher in subjects with crossed hand-foot dominance [37]. Also, in another recent study, it has been reported that athletes had no significantly lower digit ratio than sedentary subjects and there was no significant correlation between digit ratios [38]. They concluded that sexual dimorphism and handedness related differences in digit ratio like previous studies claimed [33-36] are not universal in humans.

Conclusions

The higher self-esteem scores in left-handed university students in the present study and the higher destructive aggressiveness and the less tolerance and insistence in the left-handers, may be associated with higher sports performance in the left-handed persons. In universities, because balanced self-esteem not too little and not too much self-esteem is important for success, the emotional training programs can be useful to decrease many possible psychological problems and to increase academic achievement. Results of the current study should be replicated and reconfirmed by further robust replication studies.

References

1. Crocker J, Major B. Social stigma and self-esteem: The self-protective properties of stigma. Psychol Rev 1989; 96:608–630.
2. Smith ER, Mackie DM. Social Psychology 3rd Edn. 2007; Hove: Psychology Press.
3. Marsh HW. Causal ordering of academic self-concept and academic achievement: A multiwave, longitudinal path analysis. J Educ Psychol 1990; 82:646–656.
4. www.libertaddigital.com/opinion/editorial/
5. Baumeister RF, Campbell JD, Krueger JI, et al. Does high self-esteem cause better performance, interpersonal success, happiness, or healthier lifestyles? Psychol Sci Public Interest. 2003; 4:1–44.
6. Orth U, Robbins RW. The development of self-esteem. Curr Dir Psychol Sci 2014; 23:381–387.
7. Welker KM, Norman RE, Goetz S, et al. Preliminary evidence that testosterone's association with aggression depends on self-construal. Horm Behav 2017; 92:117-127.
8. Geschwind N, Galaburda AM. Cerebral lateralization: biological mechanisms, associations and pathology. 1987; MIT press: Cambridge, MA.
9. Jamison CS, Meier RJ, Campbell BC. Dermatoglyphic asymmetry and testosterone levels in normal males. Am J Phys Anthropol 1993; 90:185-198.
10. Tan U. Serum testosterone levels in male and female subjects with standard and anomalous dominance. Int J Neurosci 1991; 58:211-214.
11. Beaton AA, Rudling N, Kissling C, et al. Digit ratio (2D:4D), salivary testosterone, and handedness. Laterality 2011; 16:136-155.
12. Aydin N, Dane S, Oztürk I, et al. Left ear (right temporal hemisphere) advantage and left temporal hemispheric dysfunction in schizophrenia. Percept Mot Skills 2001; 93:230-238.
13. Dane S, Yildirim S, Ozan E, et al. Handedness, eyedness, and hand--eye crossed dominance in patients with schizophrenia: Sex-related lateralisation abnormalities. Laterality 2009; 14:55-65.
14. Dane S, Balci N. Handedness, eyedness and nasal cycle in children with autism. Int J Dev Neurosci 2007; 25:223-226.
15. Aygül R, Dane S, Ulvi H. Handedness, eyedness, and crossed hand-eye dominance in male and female patients with migraine with and without aura: A pilot study. Percept Mot Skills 2005; 100:1137-1142.
16. Yüksel R, Sengezer T, Dilbaz N, et al. Handedness, eyedness, and hand–eye crossed dominance in patients with different addictions. Neurol Psych Brain Res 2012; 18:181-185.
17. Boukar MM, Dane S. The effects of sex, education and marital status on alexithymia. J Res Med Dent Sci 2019; 7: 82-85.
18. Christina ON, Akin OM, Salisu RA, et al. The effects of sex, physical defect on body, acne on face and education on depression in Nigerian University students. J Res Med Dent Sci, 2019; 7: 103-108.
19. Oldfield RC. The assessment and analysis of handedness: The Edinburgh inventory. Neuropsychol 1971; 9:97–113.
20. Rosenberg M. Society and the adolescent self-image. 1965; Princeton, NJ: Princeton University Press.
21. Tafarodi RW, Swan WB. Two-dimensional self-esteem: Theory and measurement. Pers Individ Dif 2001; 31:653-673.
22. Vermillion M, Dodder RA. An examination of the rosenberg self-esteem scale using collegiate wheelchair basketball student athletes. Percept Mot Skills 2007; 104:416-418.
23. Geschwind N, Behan P. Left-handedness: association with immune disease, migraine, and developmental learning disorder. Proceedinggs of the National Academy of Sciences of the United States of America 1982; 79:5097-5100.
24. Geschwind N, Galaburda AM. Cerebral lateralization: biological mechanisms, associations, and pathology: A hypothesis and a program for research. Archives Neurol 1985; 42:521-552.
25. Wood CJ, Aggleton JP. Handedness in "fast ball" sports: do left-handers have an innate advantage? Br J Psychol 1989; 80:227-240.
26. Dane S, Erzurumluoglu A. Sex and handedness differences in eye-hand visual reaction times in handball players. Int J Neurosci 2003; 113:923-929.
27. Ziyagil MA, Gursoy R, Dane S, et al. Left-handed wrestlers are more successful. Percept Mot Skills. 2010; 111:65-70.
28. Grondin S, Guiard Y, Ivry RB, et al. Manual laterality and hitting performance in major league baseball. J Exp Psychol: Human Perception Performance 1999; 25:747-754.
29. Abel EL, Kruger ML. Relation of handedness with season of birth of professional baseball players revisited. Percept Mot Skills 2004; 98:44-46.
30. Holtzen DW. Handedness and professional tennis. Int J Neurosci 2000; 105:101-119.
31. Gursoy R. Effects of left- or right-hand preference on the success of boxers in Turkey. Br J Sports Med 2009; 43:142-144.
32. Dane S, Sekertekin MA. Differences in handedness and scores of aggressiveness and interpersonal relations of soccer players. Percept Mot Skills 2005; 100:743-746.
33. Manning JT, Scutt D, Wilson J, et al. The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. Human Reproduction 1998; 13:3000-3004.
34. Manning JT. Digit ratio: A pointer to fertility, behavior, and health. 2002; New Brunswick, NJ: Rutgers Univer. Press.
35. Manning JT, Taylor RP. 2nd to 4th digit ratio and male ability in sport: implications for sexual selection in humans. Evol Hum Behavior 2001; 22:61-69.
36. Paul SN, Kato BS, Hunkin JL, et al. The big finger: the second to fourth digit ratio is a predictor of sporting ability in women. Br J Sports Med 2006; 40:981-983.
37. Abubakar NM, Nasir FT, Lojede OH, et al. Handedness, eyedness, footedness, crossed dominance and digit ratio in Nigerian people, J Res Med Dent Sci 2018; 6:62-69.
38. Aminu AM, Udeze CN, Samaila H, et al. There is no sex-, handedness and hand grip strength-related dimorphism in digit ratio in both sedentary and athletic African young people. J Res Med Dent Sci 2018; 6:108-113.