Relationship Between Second to Fourth Digit Ratio (2d:4d) and Some Anthropometric Variables to Academic Performance Among Secondary School Students in Kaduna, Nigeria.
CHAPTER ONE
Objectives of the Study
With the emergence of the importance of digit ratio as a pointer to height, intelligence, aggression, health and fertility, the present study is designed to investigate:
- The relationship between 2D:4D and academic performance among secondary schools students.
- Sex differences in 2D:4D ratio among some Nigerians
- The relationship between 2D:4D and head circumference
- The relationship of 2D:4D ratio with BMI of students
- Relationship between 2D:4D and waist, hip and neck
CHAPTER TWO
LITERATURE REVIEW
Evidence of Androgen effect on Digit Ratio
The relative length of the index finger to the ring finger, i.e., the second-to-fourth digit ratio (2D:4D), is sexually dimophic in humans and non-human species, such as other primates, rodents, avian, lizard, and amphibian species (Chang, 2008 and Voracek, 2006). In male fetuses, testosterone secretion from testes starts at about the 9th week of gestation, and testosterone levels peak between 10 and 20 weeks (Knickmeyer and Baron-Cohen, 2006), and this ratio does not change between the ages of 2 and 25 years (Manning et al., 1998) Male fetuses produce more than 2.5 times the testosterone levels observed in female fetuses (Daftary, 2006). In the second trimester, male testosterone production declines and remains at low levels until after birth (Word, et al., 1989). From around three months after birth, there is a second peak in human male testosterone levels (Andersson et al., 1998). There is now clear evidence that exposure to high testosterone levels during early development has permanent effects on various sex-typed behaviors in humans (Cohen-Bendahan, et al., 2005; Collaer and Hines, 1995).
Evidence of testosterone effect on 2D:4D is provided from the studies of males and females with congenital adrenal hyperplasia (CAH). CAH causes excessive androgen production from the adrenal glands during gestation. Although postnatal treatment brings androgen levels back to normal (Hines, 2003), CAH affected girls show masculinised and defeminised play behavior in comparison to normal controls (Hines, 2003; Knickmeyer et al., 2006). A similar effect was not observed in boys, but CAH affected boys appear to have normal prenatal testosterone levels (Hines, 2003). Although studies on girls with CAH support the idea that prenatal testosterone affects sex-typed play behavior in humans, too, these studies have limited internal validity because CAH affected girls differ from normal controls in that they have masculinised genitalia and a severe medical condition (Cohen-Bendahan et al., 2005; Hines, 2003; Knickmeyer et al., 2005). Furthermore, studies on CAH affected individuals cannot elucidate whether normal variation of prenatal testosterone within each sex has any effects on sex-typed play behavior. This question was addressed in a longitudinal study by Auyeung et al. (2006), which related amniotic testosterone (measured around the 16th week of gestation) to sex-typed play behavior at age nine years as indicated by mothers answering the Pre-School Activities Inventory (Golombok and Rust, 1993). Higher testosterone levels were clearly related to more masculine play behavior in girls and boys. Several lines of evidence indicate that 2D:4D is negatively related to early testosterone exposure. Indeed, digit ratios offer a valid test of the organizational hypothesis that androgens act early in life to masculinize various human behaviors (Breedlove, 2010) This sex difference is already apparent at the end of the first trimester (Malas, et at., 2006). The sex difference in 2D:4D as well as individual values, show considerable stability across childhood and adolescence (McIntyre, et al., 2005; Trivers, et al., 2006).
\
CHAPTER THREE
MATERIALS AND METHODS
Research Participants
The subjects that participated in this study were secondary school students from Kaduna, Kaduna State, Nigeria. (n=462, mean age 16.84 ±1.94 years)
Study Location
The study was conducted in three (3) randomly selected secondary schools in Kaduna metro police, namely Federal Government College, Kaduna, Capital School and Technical College, Kaduna. In each of the school, terminal results of the students were collected from their form masters/mistress. Anthropometric measurements of the required parameters of these students was taken.
CHAPTER FOUR
RESULTS
Analysis of Study Population
Four hundred and sixty two (n = 462) students subjects both male and females aged 13 to 23 years old were considered for this study. These were composed of two hundred and thirty nine ( n = 239) male and two hundred and twenty three ( n = 223) females. The population size cut across three secondary schools in Kaduna metro police. In each of the schools, academic records of selected subjects of each participating student was collected from the schools managements and computed against there digit ratio and other anthropometric variables.
The population size was categorized according to ethnic groups into four groups respectively: Hausa, Yoruba, Igbo and others. Then according to geopolitical zones into six groups: North- West, North-East, North-Central, South-West, South-East and South-South.
CHAPTER FIVE DISCUSSION
Discussions.
The results of this study pointed to a negative correlation between 2D:4D and academic performance as measured by grades obtained by the students in their first term examination. Three out of the four subjects considered in this study (English language, Biology and Economics) were negatively statisically not significant with digit ratio. On the other hand Mathematics scores were positively statistically significant with 2D:4D for both hands in males. This is consistent with the study of Keogh, (2011) and Brosnan, (2006) who reported positive correlation between digit ratio and numeric capabilities and ability to understand information communication technology (Brosnan, 2006; Brosnan, Gallop, Iftikhar, & Keogh, 2011), In line with our present study, Hopp et al, (2012) who found that right hand 2D:4D is negatively related to theory and practical marks in male dental students. But there is lack of a relationship between 2D:4D and examination marks in female dental students. Improved Mathematical performance in relation to lowere 2D:4D, also agree with the finding of no sex differences in the areas of number, counting, and basic mathematics (Geary, 1996). Significant relationship were also reported to exist between digit ratio i.e lower ratio potentially indicating higher prenatal testosteron was associated with better performance on the numerical measures and number, counting or simple numerical abilities in boys but not girls (Fink 2006). Recently, Coco et al. (2011) evaluated a group of 48 male medical students, and found a significant correlation between 2D:4D and success in admission tests for a school in Italy.
CHAPTER SIX
SUMMARY, CONCLUSION AND RECOMMENDATIONS
Summary
In summary, the present cross-sectional study investigated the academic performance and anthropometric parameters of students based on gender, socioeconomic status, school type, age group and ethnicity. Results of the study showed all the anthropometric variables, length of the digits and academic performance were statistically significant based on gender, academically female subjects are doing better than their males counterparts in all the four subjects considered, most especially in English Language and Biology. Geographically, students from South-East zone which represent the Igbo ethnic group performed best academically followed by Yoruba students from South- West. The Hausas from North-West zone are the least. Other anthropometric variable did not show marked significant differnce based on ethnicity.
The study also investigated the association between digit ratio (2D:4D) and future career interest of the students. Female student interested in studying Law and Sciences have the lowest ratio of 0.96 and 0.94 respectively on the right hand, while Law and Engineering has the lowest ratio of 0.95 each on the left hand. Higher ratio of 2D4D are associated with student interested in studying accounting. Digit ratio does not show statistical difference among the male subjects based on career interest. Academic performance were also significant with students interested Medicine and Sciences scoring higher marks in Mathematics and English Language. Medical and Engineering students were also found to be best in Biology and Economics. Arts and Law scores lowest in Mathematics, lowest scores in English Language was recorded for students interested in studying Accounting and Arts.
Conclusion
The study found that low 2D:4D (a correlate of high prenatal testosterone and low prenatal oestrogen) was associated with better performance in Mathematics in males, but not in females. There were no correlation between 2D:4D and academic performance, in both male and female based on the three other subjects considered among the secondary school students in Kaduna, Nigeria. The lack of correlation between 2D:4D and academic performance in female students may not be unconnected to the fact that high prenatal testosterone enhances higher intelligent but the effect of prenatal testosterone on intelligence differs between the sexes.
Recommendations
- The students should undergo the same type of examinations, and it should be conducted in the same time and the same condition so as to ensure accuracy when dealing with the academic performance. This will provides uniformity in assessment of students performance via their
- The researcher should be the one to set the type of examinations that he/she wishes. This will help to eliminate the effect of different subjects combinations of the students
- There should be large enough sample size that will come across different ethnic groups of the population, this will ensure enough participation of each ethnic groups.
Contributions to Knowledge
Academic performance of a student can be determined by the use of 2D:4D and digit length. (R = 0.29, 0.27, 0.15, 0.28, 0.26, 0.12 for R2D, R4D, R2D:4D, L2D, L4D and L2D:4Drespectively).
- Mathematics performance has high affinity to lower 2D:4D (r = 0.12 and 0.27 for right and left hand respectively).
- Contrary to the assumption that bigger head size enhances intelligence, the present study found no relationship between academic performance and head size (r = 0.03, 0.07, 0.08 and 0.03 for Mathematics, English, Biology and Economics respectively)
- In line with most studies, the research found and confirmed that academic performance favoured female students in all the four subjects (p< 0.005)
REFERENCES
- Adebisi, S. S. (2008). Medical Impacts of Anthropometric Records. Annals of African Medicine, 7; 42-47
- Akinbabijo, O. B. (2012). Urban Environmental Justice and the Missing Links: A Study of High Density Residential Districts of Kaduna, Nigeria. The built and human environment review, Volume5.
- Anderson, B. and Harvey, T. (1996). Alterations in cortical thickness and neuronal density in the frontal cortex of Albert Einstein. Neuroscience Letters, 153; 98– 102
- Andersson, A. M., Toppari, J., Haavisto, A. M., Petersen, J. H., Simell, T. and Simell, (1998). Longitudinal reproductive hormone profiles in infants: Peak of inhibin B levels in infant boys exceeds levels in adult men. The Journal of Clinical Endocrinology and Metabolism, 83; 675–681
- Anselem, E. O. E. and Ojonigu, F. A. (2010). The influence of rainfall on Hausa traditional architecture. Research journal of applied sciences, engineering and technology, 2(8):695-702.
- Aksüt S. V., Aksüt G., Karamehmetoglu A. and Oram E. (1986). The determination of serum estradiol, testosterone and progesterone in acute myocardial infarction. Japan Heart Journal, 27;825–837.
- Arato, M., Frecska, E., Beck, C., An, M. and Kiss, H. (2004). Digit length pattern in schizophrenia suggests disturbed prenatal hemispheric lateralization. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 28; 191–194.
- Areola, O., Ahmed, K., Iruegbe, O. I., Adeleke, B. O. and Leong, G. C. (2005). Certificate physical and human geography. University press public limited company, Ibadan. pp: 214.
