Abstract

The research paper is intended to determine the reason why average males are better than females in mental rotation. An important debate arising here is that perhaps boys are socialized with games, which are perceived to be related to mental object rotation than girls. Another possibility may be based on the assumption that boys are encouraged to be competitive about performance including active participation in sports and video games. Besides, the cause of the male advantage in mental object rotation may also be due to the disparity in the way males and females’ brain develop. Theoretically, Y-chromosomes, which determine masculinity, trigger the development of testes. The testes produce testosterone, which has an organizational impact on infants’ mental development. Practically, the level of testosterone in the fetus can be measured indirectly using 2D: 4D ratio, which is one of the factors for determining the gender characteristics. A lower 2D: 4d rate implies more masculinized individuals while a high 2D: 4D ratio implies more feminized individuals. The observation can be used to predict phenotypic relationships such as the length of the index and ring fingers. Males, having a low 2D: 4d ratio will long index fingers compared to females with high 2D: 4D rate, showing that the males will have a shallower slope on mental object rotation tasks.

Key Words: Cognitive development, nature-nurture controversy, genes, chromosomes, 2D: 4D ratio, and intelligence.    

Introduction

Theoretical Overview

The issue of mental rotation and its causes has been among critical factors in psychology for a very long time. Mental rotation refers to the ability of an individual to rotate a two or three-dimensional object mentally concerning the visual representation of the particular object. Many studies have revealed the difference in mental rotation between males and females. Males have been outdoing females in mental rotation, showing a unique characteristic of men over women. However, several questions have arisen concerning the significant causes of this unique characteristic that makes males better than females in terms of mental retardation (Shepard & Metzler 1971, p.702). On this note, it has been found that nature-nurture controversy plays a leading role to justify this observation. Nature, in this context, refers to genetic factors that are inherited from parents to offspring. The issue of inheritance triggers the concept of the chromosome, which are either XX for females or XY for males. From the observation concerning mental rotation, it can be said that the gene that facilitates the process is more on the Y-chromosome than on the X-chromosome. On the other hand, nurture refers to surrounding and all the experiences a person obtains due to a continuous learning process. The influence of the two aspects is what is known as the nature-nurture controversy, and it can be used to explain the difference in mental rotation across genders.

Research overview

To explore the nature-nurture controversy necessitated the use of various scientific approaches, the most applicable one being the examination of 2D: 4d ratio. The findings revealed that 2D: 4D ratios can be applied in measuring the balance of testosterone levels in the fetus, which are having organizational effects (Manning et al., 2016, p.620). In the experiment, 2D represented the index finger while 4D represented the ring fingers. This implies that an individual with low 2D: 4d ratio would be more masculine while the one with high 2D: 4D rate would be more feminine. The male advantage in the mental rotation may also be linked to the structure and functions of the Y-chromosome, which dictates all the masculinity of every male individual. The first effect that is a result of the Y-chromosome is their ability to cause gonads to become testes, which releases testosterone. Testosterone is the known organizational and activation hormone, playing the role of “masculinizing” an individual’s phenotypes before birth; hence; making the ring finger relatively longer.

The observation justifies the claim that a lower 2D: 4D ration results in more masculinity. Besides, testosterone also have other influences on the body and brain. From the theoretical view, 2D: 4D ratio shows a positive correlation with an individuals’ performance. The method is, therefore, one of the best approaches for determining the differences in mental object rotation across genders (Hooven et al., 2004, p.785). However, a major limitation of the approach usually arises due to its inability to give a specific measure of the speed of mental object rotation since; it falls across many sub-components of cognitive psychology. According to the study presented by Peters et al. (2007, p.701), the researchers measured adult testosterone levels with saliva swabs. However, our main aim was to know exactly found out the organizational effects of testosterone on slopes. Since Peters et al.’s experiment cannot solely isolate mental rotation, we will have to measure slopes in the lab.

Research Objectives

1. To determine the significant reasons or causes of male advantage in mental object rotation.
2. To determine the role of nature and nurture in the mental object rotation across different genders.

• To examine the relationship between the 2D: 4D ratio with an individual’ performance ability and the contribution of natural intelligence or cognition to the process.

Hypotheses

1. The effects of testosterone in males would explain the explanation of higher rates of mental object rotation. The overall effect of the hormone would be observed in the ratio of 2D; 4D, which should be low in males and high in females. Slopes obtained for males would be shallower compared to the one obtained for females.
2. If the experiment reveals that boys have excellent performance of practical skills such as video-games, the nature-nurture controversy plays a crucial role in male advantage in the mental object rotation.

• The relationship between 2D; 4D ratio should be directly dependent on chromosomal make-up of an individual during the prenatal stage.

Method

The research method used in this study was a quantitative research method since; the data had numerical values. Furthermore, the study utilized two research designs under the quantitative approach, which were the experimental and correlation research designs. In the preliminary study design, we recruited 42 males and measured the 2D: 4D ratio (Shepard & Metzler 1971, p.702). The primary data collection methods used in the study included observation. The participants were directly observed during the study. On the other hand, the data was recorded in tabular form since; it was numerical data.

Procedure

1. Test and comparison block shapes were presented side by side. Each object consisted of ten solid cubes attached face-to-face to form a rigid arm-like structure with exactly three right-angled “elbows,” each placed in a 5-degree visual angle circular area.
2. Angular offset was set at 10 levels, from 0 to 180 degrees (0 20 40 60 80 100 120 140 160 180).

• The 2D: 4D ratios were measured again for the participants, who were given a 20 trial block with ten similar and 20 different trials. There was a break between every 100 successful tests. There were 1600 pairs, as in Shepard and Metzler (1971, p.702).

1. First, mean RT increased with an angular offset.
2. Next, we looked at MRT for each participant.

Results

Analysis of the Results

From the theoretical overview of the study, predicting the type of correlation for the results would be possible provided the number of variables that would be included in the experimental study. Since the study involved only two variables, it was clear that linear regression would be possible for the study. Basing the arguments on the theory of the nature-nurture role on intelligence, there was a need to predict a positive correlation for the data set (Bryman & Cramer, 1990). The results obtained from the experiments showed a quantification of the slope obtained for each participant using linear regression analysis. In linear regression, there are only two variables that interact to bring about a particular observation. From the quantification of the data, it was clear that shallow slopes represented faster mental rotation implying smaller values of 2D: 4D ratios. After obtaining the quantitative data, the slope values were to the high and low 2D: 4D rations found and a conclusion was made based on the figures obtained. Smaller amounts of the 2D: 4D rations implied more masculine individuals.

From the theoretical framework of the study, it was postulated that smaller values of 2D: 4D would results in shallower slopes, while high amounts of 2D: 4D ratios would result in steeper slopes. Therefore, the results obtained showed a positive correlation between the variables of the study presented. A positive correlation realized between the two variables meant that there is a close relationship between slope and 2D: 4D ratios. An analysis of the data then showed a direct contribution of fetal hormones such as testosterone to mental object rotation speed. A regression analysis produced the graph below, which showed a positive correlation between the variables.

Discussion

When slopes and 2D: 4D ratios were measured in males, it was found that two variables showed a positive correlation, suggesting that prenatal testosterone organizes the growing brain in such a way that it is faster at mental object rotation. Based on the findings, it can be inferred that some of the sex difference is innate. A general argument that was formed from the results is the effect of testosterone in some males. Arguably, if the hormone was found to be having an impact on a certain number of males used as participants, then it can be generalized to all males, and a conclusion is made on the effects of testosterone in all males. Another essential remark that was found from the analysis of the data obtained was that correlation could be used to prove direct causation. Expounding on the point, it is clear that prenatal testosterone may make male children competitive, implying a faster mental object rotation rate. Just as it was found that the testosterone is capable of determining the phenotype of a male infant through the sizes of the index and ring fingers, the same way the hormone would lead to unique mental developmental tasks that would make the males have a faster mental object rotation.

From the observations made from the study, it is right to say that nature plays a vital role in cognitive development, which later dictates the rate of mental object rotation. ThNature here refers to the natural and involuntary factors such as the genetic make of a person. Males are usually associated with the Y-chromosome, which carries the masculine characteristics. It means that the individuals with the Y-chromosome would have testes for the production of testosterone. As mentioned earlier on the role of the hormone in infant development, it concluded that males would have a faster rate of cognitive development or natural intelligence than females of similar ages. A more rapid cognitive growth among men implies a quicker speed of mental object rotation.

On the other hand, nurture refers to all the environmental factors that may significantly affect the rate at which children are involved in mental object rotation. A continues interaction of some environmental conditions. In this view, it is assumed that a regular reminder that boys should be working hard in sports and video games can increase their mental object rotation. The more a person interacts with certain objects; they develop a theoretical image of the object that would help in visualizing the object mentally. It is therefore correct to say that practical activities have positive effects on cognition, which increases from childhood to adulthood and can be maximized through environmental interactions including socioeconomic activities.

Biologically, there are several factors associated with genetic make –up of each gender, which makes them have unique characteristics. One of the most relevant scientific considerations that may be considered in the justification of the debate is the fact that Y-chromosomes are capable of causing gonads to become testes that are designed to release testosterone, which is regarded as one of the hormones having organizational and activation effects (Lynch & Walsh, 1998, p.540). The hormone also makes the phenotype to be more masculine in males, causing their ring finger relatively longer. Genes usually account for almost three-quarters of the various factors in cognition at the population level. It is therefore correct to say that genetic effects on cognition increases from childhood to adulthood and can be maximized through environmental interactions including socioeconomic activities. Furthermore, the primary factor to be considered when tackling this topic of mental rotation is the level of cognitive developments across genders and the various aspects resulting in the different rates of cognitive development during childhood developmental period, which determines the level of a person’s intelligence.

Limitations of the Study  

One of the constraints presented by this study was the digit ratio, which only explains more than 25% of variance slopes. As a result, more variance is left unexplained. On the other hand, it is not yet known, the main reason for the substantial difference in females. The study fails to arrive at the solution. Furthermore, the study fails to clearly distinguish the extent of effects of environmental factors and genetic factors towards mental object rotation. In other words, the study does not define the elements, whether genetics or surrounding, which greatly determine the mental rotation.

Conclusion

Ultimately, the question on mental rotation and its causes has been one of the critical factors in psychology, which have resulted in a series of debates as individuals try to justify the effects of nature and nurture in process. Many studies have revealed the difference in mental rotation between males and females. Males have been outdoing females in mental rotation, showing a unique characteristic of men over women. The research paper is intended to determine the reason why average males are better than females in mental rotation. An important debate arising here is that perhaps boys are socialized with games, which are perceived to be related to mental object rotation than girls. Another possibility may be based on the assumption that boys are encouraged to be competitive about performance including active participation in sports and video games. Besides, the cause of the male advantage in mental object rotation may also be due to the disparity in the way males and females’ brain develop.

To explore the nature-nurture controversy necessitated the use of various scientific approaches, the most applicable one being the examination of 2D: 4d ratio. The findings revealed that 2D: 4D rates can be applied in measuring the balance of testosterone levels in the fetus, which are having organizational effects. It is also true that predicting the type of correlation for the results would be possible provided the number of variables that would be included in the experimental study. Since the study involved only two variables, it was clear that linear regression would be possible for the study. Basing the arguments on the theory of the nature-nurture role on intelligence, there was a need to predict a positive correlation for the data set. The results obtained from the experiments showed a quantification of the slope obtained for each participant using linear regression analysis.

References

Shepard, R. N., & Metzler, J. (1971). Mental rotation of three-dimensional objects. Science, 171(3972), 701-703.

Quéré, C. L., Andrew, R. M., Canadell, J. G., Sitch, S., Korsbakken, J. I., Peters, G. P., … & Keeling, R. F. (2016). Global carbon budget 2016. Earth System Science Data, 8(2), 605-649.

Hooven, C. K., Chabris, C. F., Ellison, P. T., & Kosslyn, S. M. (2004). The relationship of male testosterone to components of mental rotation. Neuropsychologia, 42(6), 782-790.

Bryman, A., & Cramer, D. (1990). Quantitative data analysis for social scientists. Taylor & Frances/Routledge.

Lynch, M., & Walsh, B. (1998). Genetics and analysis of quantitative traits (Vol. 1, pp. 535-557). Sunderland, MA: Sinauer.