Michael Thacker

“Investigating the evolution of consciousness through integrated symbolic, archaeological, and psychological research.”

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  • Male and Female Differentiation in Neuroanatomical Structures and Their Connectome

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    Introduction

    Since the time humans branched off from chimpanzees approximately six million years ago, humans have evolved into a larger and more complex species through influencing factors such as bipedalism, tool crafting, cooking, climate change, socialization, and pair bonding (Wrangham, 2009; Tuttle, 2024; Timmermann et al., 2024). The latter of these factors was initially accomplished through the evolutionary process of sexual selection, and with it a greater parental investment from both males and females that required greater cooperation between the sexes, as well as helped contribute to the formation of human culture (Larsen, 2023). The process of sexual selection is predominately accomplished through the selectivity of females in their choice of male mating partners that has helped shape variations between human female and male brains throughout the past two million years or so. This process has impacted males and females in different ways that have contributed to neuroanatomical and physiological differences between the sexes (Stanyon & Bigoni, 2014).

    Although sexual selection has been one of the guiding forces that have helped human evolution through a pathway that has brought about changes both physiologically and neuroanatomically that helps distinguish between male and females, it is still only the tip of the iceberg of causal factors of anatomical differences between the sexes. However, even with acknowledged differences with some that have recently been disclosed that will be discussed shortly, there are still plenty of opponents to these differences that believe there to be no outstanding differences between male and female brains at all with most differences being solely a byproduct of immediate environmental and social influences. To help address this conundrum between perspectives, this paper will first examine the field of biology in a comparative and contrasting approach to the study of sex differentiation, followed a brief overview of a flawed source claiming such a concept. From there, evidence found within recent studies will be assessed as well as a psychological theory pertaining to sex differentiation.

    Biology of Sex Differences

    Biology is the study of a living species and their vital processes with focuses on underlying processes such as genetics, hormones, cellular and immune function, among others Britannica, 2021). Although biology focuses on the physiological components of humans while the field of psychology studies the functionality of the mind, the two fields of study complement each other. With the help from biology, psychologists can better understand the underlying biological markers that help drive behavior, which is a crucial factor in understanding the psychological processes and the overall functionality of any species. Vice versa, psychology can help biologists discover root causes of certain behaviors that have been analyzed by psychologists as their work helps provide cues as to what might be underlying the behavior of interest (Garrett & Hough, 2022).

    Biology has helped shed light on the underlying biological functions that help differentiate males and females while psychology has helped compliment this information through the perceptual and behavioral differences between the sexes. For instance, males produce 15 to 20 times more testosterone than females which is linked to greater muscle mass, increased aggression and sexual drive, decreased sensitivity to stress, and risky behavior. Testosterone is also a vital hormone in the development of male sexual hormones during gestation that is accomplished by stimulating the development of the Wolffian ducts that results in male external genitalia (Garrett & Hough, 2022). This data on testosterone not only helps explain some of the biological differences between males and females, but it also helps understand neurological and perceptual differences between the sexes as well (Zitzmann, 2020).

    Flawed Source

    According to Elle Beau, a user on Medium, there are minor differences between male and female brains. The only evidence to support her claim was that most studies revealing differences between male and female brains were insignificant findings as well as flawed in their design with small sample sizes. She also states that the only genuine difference between the brains is the portion of the brain that enervates the male penis (2024).

    Peer-Reviewed Sources

    Three recent studies will be examined here to help rebuttal the flawed source as well as help further enhance the complexity of the human brain regarding gender differentiation.

    Source 1

    The first source of consideration is a large study from 2013 by Madhura Ingalhalikar and colleagues that focused on the structural connectome within the brain of both males and females. This study included 949 youths ages 8 to 22 years old with 428 being male and 521 being female. The researchers used diffusion tensor imaging (DTI) to examine the participants brains to examine the interactions among regions of the brain while computing a structural connectome of these interactions. What the researchers discovered is that there is a significant sex difference between male and female brains that suggested fundamental differences in connectivity patterns between the two. This study utilized available data that was acquired through the Institutional Review Board approval from both the University of Pennsylvania and the Children’s Hospital of Pennsylvania. The data was acquired through approval which requires informed consent from both the child involved and their parents. They also published the data which requires approval and informed consent both of which was accomplished, and thus they followed the necessary ethical guidelines of the American Psychological Association (APA) that would have been required for this study (APA, 2017).

    Noticeable differences include inter-hemispheric and intra-hemispheric connections. They found that male brains tend to develop in manner that facilitates intra-lobe and intra-hemispheric connections. This type of connectivity produces neural networks that are transitive, modular, and discrete. Females, on the other hand, showed greater inter-hemispheric connectivity that allows for greater efficiency in the integration of the analytical and sequential reasoning modes of the left hemisphere with the intuitive and spatial features of the right hemisphere. The behavioral implications of these connectome differences between the sexes have been revealed in behavioral studies mentioned in conjunction with the results of this study that include females outperforming males on attentional tasks, word and face memory, and social cognition tests, whereas males outperformed females on tasks relating to spatial processing and motor and sensorimotor speed (Ingalhalikar et al., 2013).

    Source 2

    The second source involves another large study conducted by Stuart J. Ritchie and colleagues in 2018 that examined the structural and functional aspects of male and female brains. This study used data from 5216 United Kingdom participants wherein they examined the MRI data on participants brains that included subcortical region volume, density, and surface area; white matter density; and resting-state connectivity. The researchers also utilized cognitive testing results that were acquired at the same time as the scans. The significant findings of neuroanatomical differences were that of brain volume, surface area, cortical thickness, diffusion parameters, and functional connectivity. And again, just as the previous study, this study utilized preexisting data that was acquired through the approval of usage through the UK Biobank and the University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE), as well as the informed consent of UK Biobank members, all of which follow the ethical guidelines for research presented by the APA (2017).

    Regarding cortical volume and surface differences, males had larger volume and surface areas in comparison to females, however, females showed exhibited thicker cortices. Furthermore, these differences in volume and surface area were also found to mediate a vast majority of small sex differences in reasoning abilities. The researchers also found similar results as the first study mentioned previously wherein there was greater connectivity within the default mode network in females while males showed greater connectivity in the sensorimotor and visual cortices (Ritchie et al., 2018).

    Source 3

    The last of the three studies was conducted by Srikanth Ryali and colleagues earlier this year in 2024 that utilized artificial intelligence and large multicohort functional MRI datasets consisting of 1,000 20-to-35-year young adults to help better understand sexual differences in organizational brain functionality. These differences were predominantly found in the organizational and functionality of the default mode network, striatum, and limbic network. These findings were not only replicable and generalizable, but they were also behaviorally relevant, and thus challenge the notion of a continuum in male-female brain organization. The researchers of this study obtained data upon approval from the Max Planck Institute of Leipzig, the Human Connectome Project, and the Nathan Kline Institute which also included informed consent on the part of participants. Their work was also supported and approved by the National Institute of Health, Transdisciplinary Initiative and Uytengsu-Hamilton 22q11 Programs, Stanford Maternal and Child Health Research Institute and NARSAD Young Investigator Award, and thus fulfill certain criteria of the APA code of ethics (2017).

    Significant findings of this study included the replicability and generalizability of specific identifiable brain features between the sexes, and that these features help determine the cognitive profiles of the two sexes. Specific brain features that contribute to significant differences between males and females is that of the default mode network with the posterior cingulate cortex, precuneus, and ventromedial prefrontal cortex playing the most discriminatory role. The default mode network is responsible for introspection, mind-wandering, and autobiographical retrieval, which may influence the sex-specific differences regarding self-regulatory behaviors, certain beliefs, and social interactions. Another notable difference between the sexes was found in the striatum and limbic networks. The striatum network is responsible for habit formation, reinforcement learning, and sensitivity to rewards, while the limbic system plays a role in correction of behavioral responses and expected reward value. These two systems help navigate an individual’s subjective pleasantness to experiences which may help explain differences in male and female hedonic experiences. On a final note, the differences laid out by the researchers were found to help predict cognitive profiles in males and females (Ryali et al, 2024).

    Biological Mechanisms

    When considering dimorphic characteristics of males and females, it is best to examine how both the body and mind interact to form the whole of the person. Two factors to be considered here are the effects of testosterone and estrogen, and sexual arousal and attraction. First, testosterone and estrogen play significant roles in the formation, stabilization, and motivational characteristics of both males and females. As mentioned previously, testosterone is the essential ingredient in helping determine a fetus’s destination as a male during gestation, and estrogen helps in the formation of both female reproductive parts and neuroanatomical features. Furthermore, levels of testosterone and estrogen throughout development are needed to maintain a certain level of homeostasis to provide a proper developmental trajectory, especially during the transitions of puberty (Garrett & Hough, 2022). Although testosterone levels gradually decline following the age of 30 for men, and both testosterone and estrogen decline during menopause for women, maintaining a level of homeostasis throughout most of one’s adult life is essential for both physical and mental health (Maattanen et al., 2021; Tsujimura, 2013; Lizcano & Guzman, 2014).

    Next, not only do testosterone and estrogen play a vital role in overall mental and physical health and well-being, but they also influence sexual arousal and attraction. Testosterone influences male sexual drive (Nguyen et al., 2022), and in females to a lesser extent. Both estrogen and oxytocin play a larger role in female sexual arousal as well as orgasmic intensity and pleasantness (Garrett & Hough, 2022). Not only do these hormones help moderate male and female sexual arousal, but they also help direct and motivate the partners in which to copulate. For females, estrogen levels help dictate perceived attractiveness in potential mates, especially during ovulation. During this phase of the menstrual cycle when estrogen levels are at their peak, females often desire more masculine counterparts with features that are indicative of higher circulating testosterone levels (Gildersleeve et al., 2014). On the opposite side, testosterone helps dictate perceived attractiveness in male mating selection strategies with an increased focus on more feminine characteristics such as large eyes, neotenous features, petite stature, and smaller jaws (Bird et al., 2016). These dimorphic qualities are, at least in part, due to the effects of natural and sexual selection that have helped our species dimorph into two complimentary components of the overarching landscape of reproductive success and survival of the species.  

    Natural and Sexual Selection

    Both natural selection and sexual selection have played a significant role in sexual dimorphism in the human species (Lassek & Gaulin, 2022; Stanyon & Bigoni, 2014). First, according to William Lassek and Steven Gaulin (2022), natural selection could potentially account for the dimorphism, especially physically, between males and females. This is evident in the physique differences between males and females, especially during the more primitive times of our development wherein males went out and hunted large, mobile game that required both strength and endurance, while females foraged locally and cooked the foods provided by the males. This energy expenditure demanded to accomplish daily hunting expeditions as well as carrying game that was killed, sometimes miles away, caused a larger adaptive feature for males compared to females. As this traditional practice was carried out over the course of millions of years, the adaptive morphological differences continued to expand.

    Next, and as mentioned in the introduction, sexual selection was a mating strategy that has allowed for increased variations in both biological and neuroanatomical between males and females as females often sought out larger, more muscular counterparts that featured wider jaw width and increased strength which is an indicator of increased testosterone and overall health and vitality. Females were often driven towards finding mates that only possessed such traits, but that could also utilize them as was demonstrated through male-male competition for potential mates, as well as hunting success. Males, too, played a role in mate selection, however, minor in comparison to their counterparts, wherein they often sought out more “feminine” mates that presented neotenous and juvenile facial features, and larger hip-to-waist ratio which is an indicator of higher estrogen levels, and again, increased health and vitality, especially regarding childbearing (Puts, 2013). Interestingly, these same perceived attractive biological features in the dynamics of mate selection are still present in modern society pair bonding (Garza et al, 2016), although the effects have become more subtle in their application due predominantly to modernization and increased equality (Brooks et al., 2010), and the birth control pill, among other factors (Gori et al, 2014).

    According to Stanyon and Bigoni (2014), these evolutionary selective mating strategies helped further drive the already prevalent neuroanatomical and behavioral differences among males and females that includes differences found within aggressive behavior, empathy and social skills. For instance, the propensity for aggressive behavior that is predominantly found among males that was instigated via male-male competition for mates is evident within the size of the neuroanatomical structures of the amygdala, mesencephalon, and diencephalon that are all positively correlated with the degree of male competition, along with a reduction in the size of the septum. Furthermore, increased empathetic tendencies and social skills found among females appears to be a consequence of sexual selection and pair bonding relationships along with its resultant formation of larger intergroup social dynamics that are evident further down the line of human evolution. The neuroanatomical evidence for higher capacity for empathy and social bonding among females is found within the increased density of gray matter found within the left-hemisphere that is involved in affiliation, social bonding and empathy.

    Conclusion

    As presented, sex differences do emerge both within both the physiology and neuroanatomy of males and females, and these differences are the result of contributing factors such as natural selection and sexual selection. Natural selection has helped humans evolve through the processes of selection pressure found within the environment that include such things as climate change, cooking, tool making, and pair bonding. These factors have helped shape humans both physiologically and cognitively in varying ways. Furthermore, as humans evolved and began to pair bond and cooperate within and between sexes, role playing in the form of male hunting and female gathering helped shape these sex differences that favor a larger physique for males and smaller physique for females. These role-playing effects also helped contribute to the neuroanatomical features of the brain as well wherein males acquired visual spatial skills that appear to have been the byproduct of being on the hunt and building tools and structures. On the other hand, females role-playing afforded them the essential skills of verbal communication and cooperation along with nurturance that enabled them to better care for social lives within the home and village or camp (Lassek & Gaulin, 2022).

    Sexual selection has offered its adaptive morphological effects through male and female selective features that favored certain qualities that were dimorphic in nature, and yet also signaled health and vitality. Females often sought out males that were larger in stature with a more muscular build indicative of higher circulating testosterone that provided protective benefits and higher hunting success rate that generally accompanied such features. Males, on the other hand, often sought females that were more petite in stature and neotenous in appearance that indicated higher estrogen levels and fertility. As these selective processes continued through the evolutionary pathway from homo erectus approximately 2 million years ago until recent times, sexual dimorphic qualities continued to persist.

    The evidence for such differences between the sexes, especially regarding the brain, was quite evident within the three studies provided wherein substantial differences emerged between male and female brains. The first study highlighted differences that were found using diffusion tensor imaging that revealed not only differences within certain regions of the brain between the sexes, but differences in the connectome between these regions. This difference in connectivity showed that males and females utilized different parts of the brain that helped explain differences in both behavior and perception. Another significance of this study was the fact that they utilized data from males and females during their developmental years, ages 8 to 22 years of age (Ingalhalikar et al., 2013). The second study went on to reveal how subcortical regions of the brains between males and females were different that included brain volume, surface area, cortical thickness, diffusion parameters, and functional connectivity. These differences are important to note as, again, they are often exhibited in behavioral and perceptual processes (Ritchie et al., 2018). The third and final study examined revealed an even deeper understanding of the differences between male and females by utilizing the latest technology such as AI to examine differences in both structural composition and connectivity. This study highlighted substantial differences in each of these factors that were both replicable and generalizable, and that challenges the idea of a female and male continuum of cognition that is currently being promoted (Ryali et al, 2024).

    On an ending note, as technology advances and is utilized to help map out the human brain, more evidence might be found that helps shed light not only the history of humanity and the differences within, but also where humanity might be heading. These discovered differences should not be a discriminatory marker that undermines differences between the sexes but should rather be a beacon of information that highlights diversity among the human species. If utilized properly in a cooperative manner, just as the primitive ancestors of the past, humanity could continue its trajectory of progress towards a future of endless possibilities wherein sex differences are celebrated in an egalitarian manner that promotes all to achieve whatever it is that they set their minds on.

    References

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    Beau, E. (2024). Minor differences in male and female brains. Medium. https://ellebeauworld.medium.com/ive-said-more-than-once-that-there-are-minor-differences-in-male-and-female-brains-one-of-them-bb7ea3139f9b

    Bird, B.M., Welling, L.L.M., Ortiz, T.L., Moreau, B.J.P., Hansen, S., Emond, M., Goldfarb, B., Bonin, P.L., Carré, J.M. (2016). Effects of exogenous testosterone and mating context on men’s preferences for female facial femininity. Hormones and Behavior, 85, 76-85, ISSN 0018-506X, https://doi.org/10.1016/j.yhbeh.2016.08.003

    Britannica, T. Editors of Encyclopaedia (2021, April 29). biology summary. Encyclopedia Britannica. https://www.britannica.com/summary/biology

    Brooks R., Scott I.M., Maklakov A.A., Kasumovic M.M., Clark A.P. & Penton-Voak I.S. (2011). National income inequality predicts women’s preferences for masculinized faces better than health doesProc. R. Soc. B.278810–812 http://doi.org/10.1098/rspb.2010.0964

    Garrett, B. & Hough, G. (2022). Brain & behavior: an introduction to behavioral neuroscience 6th edition. Sage Publications, Inc. https://capella.vitalsource.com/reader/books/9781544373454/epubcfi/6/10[%3Bvnd.vst.idref%3Ds9781544373447.i30]!/4

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    Gildersleeve, Kelly & Haselton, Martie. (2014). Do Women’s Mate Preferences Change Across the Ovulatory Cycle? A Meta-Analytic Review. Psychological bulletin. 140. 10.1037/a0035438. https://www.researchgate.net/publication/260376815_Do_Women’s_Mate_Preferences_Change_Across_the_Ovulatory_Cycle_A_Meta-Analytic_Review

    Gori, A., Giannini, M., Craparo, G., Caretti, V., Nannini, I., Madathil, R., & Schuldberg, D. (2014). Assessment of the relationship between the use of birth control pill and the characteristics of mate selection. The journal of sexual medicine, 11(9), 2181–2187. https://doi.org/10.1111/jsm.12566

    Ingalhalikar, M., Smith, A., Parker, D., Satterthwaite, T.D., Elliott, M.A., Ruparel, K., Hakonarson, H., Gur, R.E., Gur, R.C., Verma, R. (2014). Sex differences in the structural connectome of the human brain, Proc. Natl. Acad. Sci. U.S.A.111 (2) 823-828, https://doi.org/10.1073/pnas.1316909110

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    Lassek, W. D., & Gaulin, S. J. C. (2022). Substantial but Misunderstood Human Sexual Dimorphism Results Mainly From Sexual Selection on Males and Natural Selection on Females. Frontiers in psychology, 13, 859931. https://doi.org/10.3389/fpsyg.2022.859931

    Lizcano, F., & Guzmán, G. (2014). Estrogen Deficiency and the Origin of Obesity during Menopause. BioMed research international, 2014, 757461. https://doi.org/10.1155/2014/757461

    Määttänen, I., Gluschkoff, K., Komulainen, K., Airaksinen, J., Savelieva, K., García-Velázquez, R., & Jokela, M. (2021). Testosterone and specific symptoms of depression: Evidence from NHANES 2011-2016. Comprehensive psychoneuroendocrinology, 6, 100044. https://doi.org/10.1016/j.cpnec.2021.100044

    Nguyen, V., Leonard, A., Hsieh, T.C., (2022). Testosterone and Sexual Desire: A Review of the Evidence. Androgens: Clinical Research and Therapeutics, 3(1), 85-90. 10.1089/andro.2021.0034. https://liebertpub.com/doi/abs/10.1089/andro.2021.0034

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    Ritchie, S.J., Cox, S.R., Shen, X., Lombardo, M.V., Reus, L.M., Alloza, C., Harris, M.A., Alderson, H.L., Hunter, S., Neilson, E., Liewald, D.C.M., Auyeung, B., Whalley, H.C., Lawrie, S.H., Gale, C.R., Bastin, M.E., McIntosh, A.N., Deary, I.J. (2018). Sex Differences in the Adult Human Brain: Evidence from 5216 UK Biobank Participants, Cerebral Cortex, 28(8), 2959–2975, https://doi.org/10.1093/cercor/bhy109

    Ryali, S., Zhang, Y., de los Angeles, C., Supekar, K., & Menon, V. (2024). Deep learning models reveal replicable, generalizable, and behaviorally relevant sex differences in human functional brain organization, Proc. Natl. Acad. Sci. U.S.A.121 (9) e2310012121, https://doi.org/10.1073/pnas.2310012121

    Stanyon, R. & Bigoni, F. (2014). Sexual selection and the evolution of behavior, morphology, neuroanatomy and genes in humans and other primates. Neuroscience & Biobehavioral Reviews, 46(4), 579-590, ISSN 0149-7634, https://doi.org/10.1016/j.neubiorev.2014.10.001

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    Tsujimura A. (2013). The Relationship between Testosterone Deficiency and Men’s Health. The world journal of men’s health, 31(2), 126–135. https://doi.org/10.5534/wjmh.2013.31.2.126

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    Wrangham, R. (2009). Catching fire: how cooking made us human. Basic Books.

    Zitzmann M. (2020). Testosterone, mood, behaviour and quality of life. Andrology, 8(6), 1598–1605. https://doi.org/10.1111/andr.12867

  • Two Years Alcohol-Free

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    Today marks 2 years alcohol-free. I personally struggled with alcohol for years prior to finally quitting and detoxing myself. The journey has been quite enlightening as I have put my focus on my family, my health, my work and schooling, and my relationship with God. My wife has been front and center in helping me overcome my demons, and to her I cannot thank enough. I have transformed for the better, and the journey does not end there.

    The pinnacle message of the gospels, besides the belief in Christ, is the concept of transformation. This profound concept should not be sought out in a lighthearted fashion, but is something that should be endeavored in a manner that constitutes the whole of one’s being. It is an attempt to refashion the self through physical, psychological and spiritual exploration and application.

    We are complex creatures, and often times we are quite distinct within our own self. Made up of sub-personalities and diverse personas, a unification through the process of transformation is required. The concept of transformation through the “spirit” is not solely a union of the self with God, but also a unification of the self within itself, we becoming one with the Source and one within our self. Only when we become unified are we able to utilize the potential that resides within.

    The book of James expounds on this well as the author states that we should be patient and allow the various trials and tests, which to a varying degree should be sought out in an experimental fashion, mature and transform our implicit potential into explicit reality. Through the process of learning and growing do we become more unified in our self that enables us to manifest the potential within, and the more efficiently and effectively we are able to contend with reality as such.

    Again, this same concept is echoed in the teachings of Christ in the book of John when speaking of the vine and the branches, and how we (branches) should be pruned (transformed) in order to make manifest the potential within us that brings God the glory. This pruning effect implies the death of what once was in our life that hinders our growth, whether this be substances, unhealthy foods, faulty interpretational schemas, and the like, which gradually unifies the self. By seeking out novel information while ridding ourselves of hinderances, we can transform and become what has laid dormant within.

  • Quandary Mountain Hike

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    I got a chance to hike up Quandary mountain through the Quandary Peak Trail that provides a 3.2 miles hike up to the summit followed by a 3.2 mile trip back down. Elevation change is approximately 3,300 feet. I managed to trek to the summit in 2 hours followed by a 2 hour descent that totaled to a 4 hour round trip. Thank God for keeping me safe throughout the trip.

    Watch hike here:

  • The Evolution of Gender Differentiation in Mate Choice and Sexual Preferences

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    Introduction

    For the past seven million years of human evolution, humans have survived and thrived through the mutative and adaptive processes of both natural and sexual selection. Alterations of gene expression along with the transformation that humans undertook with each passing subsequent generation was a vital necessity in the process of the survival and progression of the species (Goldberg et al., 2018; Hosken & House, 2011). Through these two selective processes, males and females have both mate choice and sexual preferences inherit in their biological and perceptual systems. These systems help guide not only mating and sexual preferences, but corresponding behaviors that help achieve such mating success. This is paramount in understanding gender differentiation regarding sexuality. Another theory to be considered when analyzing gender differentiation in sexual behavior is that of sexual economic theory which is concomitant with that of sexual selection. This theory posits that males and females exchange resources in effort to fulfill mating desires through the process of weighing costs and benefits in choosing mates. Females generally seek out financial security and a stable partner to help raise offspring by providing an exclusive sexual engagement and social contract with a male counterpart (Baumeister et al., 2017).

    In addition to understanding gender sexuality differentiation, there must also be clarification as to what classifies a pathological means of sexual behavior among the genders and a healthy means. Although a majority of the population adheres to a “healthier” means of achieving sexual satisfaction, there are those in the sexual minority camp that do not. This, of course, is not to say that all those that reside outside of the average pathway of sexual satisfaction are deemed unhealthy behaviors, but rather that within this camp there are those that push the bounds to the point of healthy maintenance, while there are others that have allowed sexual satisfaction to become the overarching aim of their perceptual framework. Those that are deemed unhealthy sexual seekers are best defined as desires and behaviors that consume an individual’s existence while neglecting all other matters such as family, work, health and well-being, friendships, etc. (King & Regan, 2019).

    Sexual Selection

    Sexual selection theory, first postulated by Charles Darwin in the 19th century, refers to the mating choice and success between males and females for reproductive purposes. Females are those that choose mates based off certain “healthy traits” exhibited through physical and psychological characteristics and abilities, while males compete amongst each other for social hierarchal position for increased selectivity of female mating opportunities (Jones & Ratterman, 2009). These traits are indicative of “good genes” that are then carried through subsequent generations which are aggregated across time that produce stronger, healthier, and more intelligent generations that help the survival and propagation of the species as a whole (Hosken & House, 2011).  

    Sexual Economic Theory

    As mentioned previously, sexual economic theory postulates that males and females exchange resources (generally exclusive sexual access from females in exchange for wealth and security from males) through a process of weighing out costs and benefits in potential mate interaction. This strategic means of mating is predicated upon a supply and demand dynamic wherein female access is a demand and the number of available females a supply, although this can shift with any given context where there is an imbalance in gender ration where females outnumber males, and thus supply exceeds demand and the price for sex is low. In this framework, females compete among one another to appear more attractive for potential male mates, while males compete against one another to seem like a better provider than their rivals. (Baumeister et al., 2017).

    Gender Difference in Mate Selection

    Both sexual selection and sexual economic theory have been defined, and yet what do these theories have to do with male and female differences in sexuality? First, a better understanding of mate preference and selection among the two genders should be attained before light can be shed on sexual preferences and differences. According to sexual selection, mate preferences among males and females have evolved wherein females tend to prefer more masculine type males that are physically fit, taller than average, industrious, brave, symmetrical (Peters et al., 2009), and high socioeconomic status, all of which are indicative of higher testosterone levels and good overall health, which also equate to healthy offspring. Moreover, males prefer females that are younger, neotenous, facial femininity, low hip-to-waist ratio, and petite-like features. Mating strategies among males and females have also evolved differently with females seeking out long-term partnerships while males generally desire short-term sexual engagement. Although there are quite a few distinctive differences between males and females regarding mate preference, there are also similarities between the genders when it comes to long-term mating strategies that include desired traits such as respectful, kind, trustworthy, and committed (Buss, 2023).

    In relationship to sexual economic theory, males and females differ in their exchange of resources with males seeking the resource of exclusive sexual access in exchange for resources of economic security and status. This exchange rate, of course, comes at an even greater costs for females besides solely allowing access to sexual intercourse, but also the potential for pregnancy. This supply and demand dynamic has influenced females to prefer male mates that are high socioeconomic status and willing to commit to a long-term relationship, while males prefer female mates that are attractive and sexually promiscuous, often through the perceptual lens of a short-term mating strategy (Baumeister et al., 2017).  

    Gender Differences in Sexual Preferences

    With sexual selection and sexual economic theory in mind, how do these two theories help increase understanding of gender differences in sexuality? The short answer is mostly through the long-term impact and influence of the reciprocal environmental, social, and interpersonal factors mentioned earlier that have shaped both the perceptual system and brain that males and females possess. This process of reciprocal influence can be broken down into three primary domains: Long-term versus short-term mating strategies, perceived attractiveness, and testosterone.

    Females on average desire more intimate, long-term relationships with a male counterpart while the opposite is true of males. This long-term strategy among females has helped influence a sexuality orientation that favors more intimate, romantic, and affectionate characteristics. Males on the other hand prefer more explicit and visual imagery when engaging in sexual activities that is related to predominately physically attractive features which reflects a more spontaneous and short-term mating strategy. Even though males predominately mate in accordance with perceived attractiveness, females too seek out partners, although to a lesser degree, that are attractive (King & Regan, 2019). One study conducted by Sherlock and colleagues found that higher rated orgasms among female participants were more frequent when engaged with a partner who was perceived as attractive compared to less attractive partners (2016).

    Testosterone is another factor that plays a rather large role in sexual propensity among the male population as it helps increase sexual drive (Corona & Maggi, 2022), and it is associated with characteristics of increased appeal that females seek out in their male counterparts such as increased height and muscle mass (Peters et al., 2009). Heightened testosterone is also linked to increased assertiveness and dominance (Knight et al., 2022), which can be associated with the sexual fantasy of dominance that is favored by men and sexual submission that is favored by women (King & Regan, 2019). Moreover, females during ovulation, which is a time of increased sex drive, prefer more masculine males that is associated with higher testosterone levels (Little et al., 2013).

    The Effects of Social Changes on Mate and Sexual Preferences

    Although the selective mating patterns mentioned previously are still evident today among males and females, both social changes and technological advancements such as oral contraceptives, gender equality, and lower sexual engagement have shifted the initial perceptual mate preferences in another direction. For instance, oral contraceptive cause females to not ovulate, a time wherein females estrogen levels increase dramatically which contribute to increased perceived attractiveness by males (Roberts et al., 2004). Moreover, this anti-ovulation feature of oral contraceptives is also shifting females to become more attracted to less masculine males (Little et al., 2013).

    The influence of gender equality in modern society has revealed its benefits for all of society, and yet there are changes that have influence the sexual dynamic interplay between males and females. These factors include the lowered desire for a high socioeconomic status in potential male partners (March & Grieve, 2014), and an increased prevalence for a dominant position during sexual intercourse (King & Regan, 2019). Another social change of consideration is that of lower levels of sexual engagement and increased celibacy among both males and females. From 2000 to 2016, men report an overall decline of weekly intercourse dropped from 60% to 47%This change in sex drive is multifaceted with influencing factors such as increased phone and internet usage, longer commutes, and financial stress (Castleman, 2021).

    References

    American Psychological Association, (2019). Ethical Principles of Psychologists and Code of Conduct. https://www.apa.org/ethics/code

    Baumeister, R., Reynolds, T., Winegard, B., & Vohs., K.D. (2017). Competing for love: Applying sexual economics theory to mating contests. Journal of Economic Psychology. 63, 230-241. https://doi.org/10.1016/j.joep.2017.07.009

    Buss, D., (2006). Strategies of Human Mating. Psychological Topics. 15. https://www.researchgate.net/publication/41391479_Strategies_of_Human_Mating/citation/download

    Buss, D., (2023). The Sexual Selection of Human Mating Strategies: Mate Preferences and Competition Tactics. 10.1093/oxfordhb/9780197524718.013.1.  

    Burtăverde, V., & Ene, C., (2021). The influence of environmental and social characteristics on women’s mate preferences. Personality and Individual Differences, 175, 110736, ISSN 0191-8869, https://doi.org/10.1016/j.paid.2021.110736

    Cameron, J. J., Stinson, D. A., (2022). Ethical Gender/Sex Measurement in Canadian Research. Canadian Psychological Association, 63(4), 536–544. https://doi.org/10.1037/cap000033

    Corona, G., & Maggi, M. (2022). The role of testosterone in male sexual function. Reviews in endocrine & metabolic disorders, 23(6), 1159–1172. https://doi.org/10.1007/s11154-022-09748-3

    Goldberg, A., Uricchio, L., & Rosenberg, N., (2018). Natural Selection in Human Populations. Evolutionary Biology – Oxford Bibliographies. DOI: 10.1093/OBO/9780199941728-0112

    Hosken, D. J., House, C. M., (2011). Sexual selection. Current Biology, 21 (2), R62-R65, ISSN 0960-9822. https://doi.org/10.1016/j.cub.2010.11.053

    Knight, E. L., Morales, P. J., Christian, C. B., Prasad, S., Harbaugh, W. T., Mehta, P. H., & Mayr, U. (2022). The causal effect of testosterone on men’s competitive behavior is moderated by basal cortisol and cues to an opponent’s status: Evidence for a context-dependent dual-hormone hypothesis. Journal of personality and social psychology, 123(4), 693–716. https://doi.org/10.1037/pspa0000305

    Little, A. C., Burriss, R. P., Petrie, M., Jones, B. C., & Roberts, S. C. (2013). Oral contraceptive use in women changes preferences for male facial masculinity and is associated with partner facial masculinity. Psychoneuroendocrinology, 38(9), 1777–1785. https://doi.org/10.1016/j.psyneuen.2013.02.014

    National Academy of Sciences (US); Avise JC, Ayala FJ, editors. In the Light of Evolution: Volume III: Two Centuries of Darwin. Washington (DC): National Academies Press (US); 2009. 9, Mate Choice and Sexual Selection: What Have We Learned Since Darwin? Available from: https://www.ncbi.nlm.nih.gov/books/NBK219729/

    Peters, M., Simmons, L. W., & Rhodes, G. (2009). Preferences across the menstrual cycle for masculinity and symmetry in photographs of male faces and bodies. PloS one, 4(1), e4138. https://doi.org/10.1371/journal.pone.0004138

    Price, G. C., Jansen, K. L., & Weick, M. R. (2020). Let’s talk about sex: Ethical considerations in survey research with minority populations. Translational Issues in Psychological Science, 6(3), 214–222. https://doi.org/10.1037/tps0000270

    Qiao H. (2018). A brief introduction to institutional review boards in the United States. Pediatric investigation, 2(1), 46–51. https://doi.org/10.1002/ped4.12023

    Roberts, S. C., Havlicek, J., Flegr, J., Hruskova, M., Little, A. C., Jones, B. C., Perrett, D. I., & Petrie, M. (2004). Female facial attractiveness increases during the fertile phase of the menstrual cycle. Proceedings. Biological sciences, 271 Suppl 5(Suppl 5), S270–S272. https://doi.org/10.1098/rsbl.2004.0174

    Sherlock, J. M., Sidari, M. J., Harris, E. A., Barlow, F. K., & Zietsch, B. P. (2016). Testing the mate-choice hypothesis of the female orgasm: disentangling traits and behaviours. Socioaffective neuroscience & psychology, 6, 31562. https://doi.org/10.3402/snp.v6.31562

  • Courage When Facing The Enemy

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    First, continued prayers for Israel and all those that have been affected by the brutal attacks. The devastation is surreal.

    Second, let this be an awakening for the Christian church, especially the men within. Understand that this world is not the illusionary dream-like landscape we inhabit each day here in America, and throughout much of western society. Through this many have become lazy and apathetic in our approach to life, while at the same time relying on authority, much of whom are controlled by the enemy, to solve our problems.

    At any given moment an enemy can attack, and according to end time prophecy, they will attack someday soon. The church must come to grasp the fact that the end is near, and this means that, just like the what happened in the Soviet Union and Nazi Germany, the new world order will be coming for you and your family.

    At this moment, most Christians are quick to point to a pre-tribulation rapture scenario, and yet no where in the Bible does it indicate such an event. Time and time again it states that the coming of Christ transpires following the tribulation era. This is just one of many: but

    ““Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light; the stars will fall from heaven, and the powers of the heavens will be shaken. Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory. And He will send His angels with a great sound of a trumpet, and they will gather together His elect from the four winds, from one end of heaven to the other.”

    Matthew 24:29-31 NKJV

    With that being stated, what should the church do? Watch and be ready. Stop living the life the elites want you to live; stop overeating, being lazy, not praying, and not studying.

    We are called to pay attention and to be ready. We must train like good soldiers of Christ, so when the enemy arrives, we are at least somewhat physically and mentally prepared to protect our families, friends, and communities.

    And with 80% of the American population being overweight, at this moment, the enemy is going to have a field day slaughtering any and all that try to intervene.

    The church has become weak, and this weakness, unfortunately, is due mostly to the lie that the elites promoted in our modern society: “Eat, drink, and be merry. Buy up what you will while you can, and live the American dream.” The part they left out: “For tomorrow you and your family will die.”

    “Watch, stand fast in the faith, be brave, be strong.”

    I Corinthians 16:13 NKJV

    Let us stand up against the evil that is coming, and get in touch with our ancestral roots wherein they lived a life of survival of the fittest, as there is a time coming soon where the fittest will be the ones who remain at the coming of Christ following the tribulation. We cannot let the Antichrist and his minions have it so easy, but rather give them the fight of their lives.

    -Michael Thacker

  • The Flood and Tyranny

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    I will be going live on both this Sunday, October 8th, at 5 pm central for the fourth lecture of the Examining The Christian Faith series. In this lecture, we will be examining pre-flood history, the flood itself, the Tower of Babel, and the emergence of civilization.

    We will begin by first taking a look at the story of Cain and Abel and the idea of morality and sin. We will examine various interpretations of this story to try to make sense of what is being told in the compacted literature.

    We will then go on to investigate the evidence for a pre-flood society. We will delve into the timeframe of this hypothetical society and its destruction by a cataclysmic flood and look at what evidence there might be for such an event.

    From there, we will examine evidence for a post-flood culture, including Noah and the Tower of Babel. We will look at how these early societies helped shape and influence the later emergence of civilization in Sumer and Egypt approximately 5,000 years ago.

    I hope you can join, and God bless.

    -Michael Thacker

  • Introduction To The Power of Ideas | Examining The Christian Faith

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    Join me this evening at 5 pm central on YouTube for the introductory lecture to the “Examining The Christian Faith” series, Introduction To The Power of Ideas. In this lecture, we will examine what it means to say one believes in something, such as ideas or religions. We will begin by looking at the concept of interpretation and that of traditionalism and progressivism.

    From there, we will see how our perception changes how we interpret ideas and reality and how, in a reciprocal manner, ideas can shape our perception. This will be examined through the work of Iain Mcgilchrist’s dual hemisphere perception.

    Following this examination, we will then go on to investigate some of the popular ideas that have influenced modern culture from the works of figures such as Karl Marx, Friedrich Nietzsche, Carl Jung, and, of course, Jesus Christ and the apostles. We also take a look at what type of influence their ideas had on society and culture, whether positive or negative.

  • Did God Condone Rape In The Old Testament?

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    Did God condone rape in the Old Testament? Those opposed to the Bible and the belief therein are quick to point out Deuteronomy 22:28 where many believe that it suggests rape to be no issue. But how true is this, exactly?

    Help support my work by donating through PayPal: https://www.paypal.com/donate/?cmd=_donations&business=9ZTKGRFY84HAA&item_name=Donation&currency_code=USD&fbclid=IwAR1JUn6QnR6vcuhZAJkQ-nYqx0fhEW0hfR71WpcZdur4HgnvWzCw_DDa7mQ

    Or donate through Venmo: @Michael-Thacker-7

    For more on the Old Testament, check out ⁠Paul Copan’s book, “Is God A Moral Monster?” on Amazon: https://amzn.to/45MKMEa

    Check out my interview with Paul Copan here:

  • Examining The Christian Faith Lecture Series

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    I am excited to announce that I will be hosting a ten part lecture series starting next Sunday, September 17, live at 5 pm central time on both YouTube and Facebook. This series will by far be the most strenuous and in-depth that I have sought to teach, with an array of various topics to be covered throughout the series that include Christian theology, philosophy, psychology, evolutionary theory, quantum physics, archaeology, and more.

    YouTube: https://youtube.com/@Michael-Thacker?si=DWpnpf8vsQRWr8d6

    Facebook: https://www.facebook.com/mike.thacker339?mibextid=LQQJ4d

    I have laid out the list of titles to each lecture below, along with a brief overview of what is expected to be covered. I hope you can join me on this journey, and God bless.

    •Introduction to the power of ideas: An introduction to how ideas change our perception, and ultimately drive our behavior. Examination of historical repercussions of ideas.
    •Creation and evolution: Investigate the Big Bang and the case for an intelligent design. Examine evolution in conjunction with Genesis.
    •The emergence of consciousness: Delve into what consciousness might be and how it manifest in the human brain. Explore the emergence of consciousness in the story of the Garden of Eden and it’s possible historical connection to evolutionary theory.
    •The flood and tyranny: Examine the flood and evidence for the event. Investigate the tyrannical elements of the Tower of Babel.
    •The Exodus: Look at evidence for the events from Abraham to the Judges, and the real mount Sinai. Examine the Old Testament Law and its significance.
    •The birth of Christ: Examine the stories of the birth of Christ from the gospel of Matthew and Luke. Delve into the theology and overall significance of the sermon of the mount.
    •The Transfiguration: Explore what the transfiguration of Christ represented and how it applies to the transformation of the Christian life. Connect this with psychological and philosophical works.
    •Death and resurrection: Explore the significance of the death and resurrection of Christ for the Christian and humanity alike. Cross-examine this story with other ancient death and resurrection stories for similarities and differences.
    •Apostolic Journey: Examine the journey of the apostles and evidence for their existence. Investigate their writings and teachings, and how they apply to the Christian life.
    •Second Coming: Investigate the second coming of Christ, the rapture, and end time scenario. Examine the biblical and scientific evidence for the destruction of the universe and birth of a new one.

    -Michael Thacker

  • The Big Bang, The Big Crunch, and The Bible

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    What does science and the Bible have to save about the creation and death of the universe? Do they both align in their ideas? Both the Bible and science state that the universe had a beginning, and it will have an end. The most recent research on dark energy has revealed that the universe is likely to end in a Big Crunch some 60-120 millions years from now, going back to the state of the singularity.

    The Bible states a similar occurrence in both the book of 2 Peter and Revelation wherein the universe will collapse upon itself while burning everything up in due process. From there, the universe will experience another Big Bang with the birth of a new version of itself. The famous physicist’s, Roger Penrose, claims a similar idea as he believes the universe will collapse upon itself and birth a new universe in its place.

    -Michael Thacket