Problems arise when proximate explanations, like sociocultural theories, are used in place of ultimate explanations, or evolutionary theories, to explain human characteristics.  ~ Alex Mackiel

In my last post (First Principle: Acknowledge Male-Female Differences), I underscored the need to acknowledge differences between men and women in their sexual psychology and response in preparation for understanding sexual orientation and the sexual fluidity of women.  I outlined twenty-two domains of difference. Several of these domains (such as #15 – “influence of context”) directly clarify the causes and expression of female sexual fluidity, or as researcher Lisa Diamond describes it, the “situation-dependent flexibility in women’s sexual responsiveness.”  I will address all manifestations, causes, and effects of women’s sexual fluidity in future posts.

Thanks for Letting Me Set the Foundation

Today’s post is very “inside-baseball” and may have limited appeal to casual readers.  What follows is not popular, titillating, twitter-ready, easy-to-eat-like-candy fluff psychology.  Intellectual integrity and rigor demand that consideration of female sexual fluidity (in this particular cultural moment) revisit basic concepts of evolutionary psychology and address misconceptions about its tenets (see Appendix).  I explain and defend evolutionary psychology as an educator and reluctant contrarian to the dominant narratives of the academic social sciences and politically-correct thinking.  Reviewing concepts of evolutionary psychology will provide a foundation for understanding the biological and cultural adaptations of female sexuality.

Women’s Sexual Functioning Demonstrates Biological and Cultural Adaptations

Women’s sexual functioning includes sexual attractions, romantic affections, sexual practices/behaviors, and preference/orientation identities that are different from men’s sexual functioning due to biological and cultural adaptations.

Evolutionary Psychology Explains Biological and Cultural Adaptations

Basic tenets of evolutionary psychology (EP) undergird the arguments and evidence about female sexual fluidity (see What is Evolutionary Psychology?) and clarify the interplay of biological and cultural adaptations that operate in female sexual psychology and response. 

How or Why “Situations” Trigger Female Sexual Fluidity

If female sexuality is “situation-dependent,” we must understand not only what situations trigger same-sex attractions, bi-sexual identity, or hetero-flexible behavior, but how or why those situations operate as triggers.

Move “Upstream” to Understand Adaptations

Acknowledging the evolved behavioral differences between men and women is a “first principle” that explains the difference between the sexual psychology of men and women; it certainly explains different degrees of sexual fluidity.  But we might need to move “upstream” one step further to understand how behaviors become adaptive over thousands of years of human evolution.  We must clarify the difference between ultimate and proximate causes to completely understand modern-day female sexual fluidity.

Female Sexuality is Sensitive to Context

Female sexuality is dramatically sensitive to context.  Women are more context-dependent than men; all external circumstances of everyday life influence the context surrounding a woman’s arousal, desire, orgasm, choice of partner, and orientation identity.  Situation-dependent equals context-dependent.  Women’s “situation-dependent” sexual fluidity implies the power of proximate causes, but it does not eliminate the possibility of ultimate causes driven by evolutionary adaptation.

Causes of Sexual Fluidity and Patterns of Expression

My next post will address “ultimate” (evolutionary) causation theories for female sexual fluidity, such as the alloparenting hypothesis.  After that, I will handle the “juicy” stuff:  patterns of desire (and its three elements), sexual behavior, and sexual orientation identities.  Importantly, research suggests functional independence (potentially) of these patterns for any particular woman.  You can begin to see the possible permutations of female sexual expression.

Definition and Overview of Evolutionary Psychology

Evolutionary psychology (EP) is the study of human nature – meaning the study of evolved psychological mechanisms or psychological adaptations.  An adaptation is a product of evolution by natural and sexual selection that allows the human species to solve particular problems — most importantly, problems of survival and reproduction.  EP contends adaptations are behind most of our preferences, desires, and emotions and incline us to behave specific ways.  EP is particularly focused on behavior traits that appear to be universal across human populations.

Culture and Nature are Part of Evolutionary design

EP believes humans are born with an innate nature and that culture and learning are part of the evolutionary design and, thus, also innate.  This blend of intrinsic nature and culture is called the “dual inheritance” model of human evolution which explains how we are “structured prior to experience.”

Psychological Adaptations Operate Beneath Conscious Thinking

Psychological adaptations exist in the brain and operate primarily beneath conscious thinking.  For example, male sexual jealousy is an evolved psychological mechanism that prevents cuckoldry and investment in children who will not carry the man’s genes into the next generation.  EP explains human behavior in terms of the interaction between these evolved psychological mechanisms and the current environment in which they express themselves.

Adaptations Emerge at Appropriate Time

Adaptations do not need to appear at birth.  Many adaptations develop long after birth (e.g., walking by humans and development of female breasts).   With some exceptions, an adaptation “must emerge at the appropriate time during an organism’s life in reasonably intact form, and hence be characteristic of most or all of the members of a given species” (Buss, D.M. 1999, p. 36).

Proximate Causes Are Triggers for Female Sexual Fluidity

Evolutionary psychologists examine proximate and ultimate causes of behavior.  Proximate causes of behavior often include stimuli in the immediate environment of the organism or physiological mechanisms inside the organism.  Such stimuli include the current cultural triggers of female sexual fluidity.

When and Where Our Mind Developed – the Timing of Ultimate Causation

Humans (the genus Homo) appeared between 1.5 and 2.5 million years ago, in a time roughly coinciding with the start of the Pleistocene Epoch.   Because the Pleistocene ended only 11,700 years ago, most human adaptations either newly evolved during the Pleistocene or were maintained during that era.   EP, therefore, proposes that the majority of human psychological mechanisms are adapted to solve survival and reproductive problems frequently encountered in Pleistocene environments.

Ultimate Causes from the Ancestral Past

Ultimate causes of behavior evoke our ancestral past and address behavior or psychological processes that were adaptive for survival-based natural selection or reproduction-based sexual selection.  Ultimate causes of a behavior pertain to our evolutionary (phylogenetic) history, addressing these questions (for purposes of this discussion):

How did female sexual fluidity come to be?  How was it adaptive? How did it confer reproductive benefits to individuals with this behavior?

Evolutionary “Situationalism” – Proximate Causes of Survival and Reproduction

EP seeks to understand both proximate and ultimate causes of species-typical psychological processes in light of basic evolutionary theory.    Modern-day EP posits “evolutionary situationalism” (Geher, G. 2014).  Situational factors that matter most in affecting behavior are the ones that bear directly on factors associated with survival and reproductive success. Five decades of feminism and women’s economic progress and political empowerment are likely contributing proximate causes of female sexual fluidity.  (To be explained in subsequent posts.)

Alloparenting is a Proposed Ultimate Cause of Female Sexual Fluidity

The theory of alloparenting is a proposed ultimate cause of female sexual fluidity.  It posits that sexual fluidity in women is a contingent adaptation that increased ancestral women’s ability to form pair bonds with female alloparents who helped rear children to reproductive age.  Under this view, most heterosexual women are born with the capacity to form romantic bonds with both sexes. (My next post will explain this in-depth.)

Interplay of Biological and Cultural Adaptations

EP sees total congruence between learning and evolution; they are natural explanatory partners – perfectly compatible.  Many evolutionary hypotheses are about learning.  Humans are endowed with evolved learning mechanisms embodied in the brain.   For instance, the claim that humans have an evolved fear of snakes and spiders does not mean that people are born with this fear.  Instead, it means that humans are endowed with an evolved learning mechanism that acquires a fear of snakes more easily and readily than other fears. Learning itself is a Darwinian process and provides one of several possible mechanisms of inheritance in addition to conventional genetic processes.

Nature versus Nurture is a Strawman Debate

It should be clear by now that nature versus nurture is an antiquated “strawman” debate*, especially as a critique of evolutionary psychology.  (See Appendix below.)  Ultimate and proximate causes easily co-exist – but it is the “nature” part of the equation, the research about ultimate evolutionary causation, and the evidence of evolved behavioral sex difference that have been under-reported and too often dismissed in the halls of contemporary political and academic inquiry.

Problems arise when proximate explanations, like sociocultural theories, are used in place of ultimate explanations, or evolutionary theories, to explain human characteristics.

Sociocultural and Evolutionary Explanations Are Not at Odds

Sociocultural and evolutionary explanations are not necessarily at odds with each other.  Evolutionary psychology is an interactionalist framework.  Human minds created culture in the first place.  Both operate simultaneously to cause most human actions, such as aggressive behavior.  It would be virtually impossible for humans to acquire and learn their culture and all its complexity without innate mechanisms in place to make it happen.

Evolutionary psychologist Glenn Geher offers, in summary: “Given this focus on both environmental and innate causes of behavior, coupled with a genuine focus on proximate and ultimate cause of behavior, evolutionary psychology is truly an approach to psychology that embraces both the nature and nurture side of that debate” (Geher, G., 2014, p. 22).

Conclusion and Summary

There are both ultimate and proximate causes of female sexual fluidity.  My next post will describe the ultimate cause(s).  After that, I will address the more proximate, modern-day situational causes and expressions of women’s same-sex orientation and bi-sexual and hetero-flexible behavior.  All of this rests on the foundation of evolutionary science – or at least an appreciation of how the field of evolutionary psychology informs the discussion.**  But the contexts or “situations” in our current sociocultural moment are rich with nuance and ripe for observation. Why did your mother take up with a woman in her fifth decade of life in 2021?  I will get to that.

Notes

*A strawman is a fallacious argument that distorts an opposing stance in order to make it easier to attack.  EP has been attacked for supposedly not incorporating “nurture” in its framework.

**Sources Outside of Evolutionary Psychology

It is worth reminding you that MatingStraightTalk draws heavily on psychologists, sexuality educators/researchers, social scientists, neurobiologists, and investigative journalists that fall outside the ranks of evolutionary psychology but whose work mostly corroborates evolutionary ideas about the context-driven, proximate causes of female sexual fluidity.

The theories and writing of Emily Nagoski (Come As You Are) are very on target.

See blog posts:

• Sexual Non-concordance: Recipe for Relationship Confusion
• Is Your Sexual Foot on the Accelerator or Brake?
• Spontaneous and Response Desire – the Underbelly of Heterosexual Mating

Also relevant are these posts: 

• Turn Off the Brakes! Making the Most of Responsive Desire
• Why Women Are Bored in Monogamous Relationships
• Addressing Barriers to Female Sexual Pleasure – Let’s Get Educated.

I will give an in-depth analysis of Lisa Diamond’s seminal work (Sexual Fluidity, Understanding Women’s Love and Desire) and Jennifer Baumgardner’s book, Look Both Ways, Bisexual Politics. Baumgardner relates her personal story and the stories of women in the 70’s and 80’s.  These women were at the leading edge of discovering, integrating, and “coping” with the milieu of the women’s movement through the lens of sexual identification and sexual practice.

Appendix: Correcting Misconceptions about Evolutionary Psychology

• EP does not focus mainly on mate selection and reproduction.
  While research on evolved behavioral sex differences has been prolific, the broader field studies parenting, education, politics, emotions, morality, aggression, mental health, physical health, technology, and mismatches of evolutionary design in the modern world.

• A belief in evolved behavioral sex differences does not negate support for women’s equality and political empowerment.
  Most evolutionary psychologists reside in academic institutions; survey research of these psychologists shows a decided leaning to the political left generally representative in the academic community.  Many feminist scholars do indeed disparage evolutionary psychology.  The bias is so strong that it has been studied as a separate phenomenon. Steven Pinker in The Blank State explains an EP position that equality is not sameness: “equality is not the claim that groups of humans are interchangeable; it is the moral principle that individuals should not be constrained by the average properties of that group.”  EP also supports equal access to all rights and privileges of economic power and role flexibility for both sexes.

• EP does not claim that products of evolution are present at birth or emerge very early in development.
  This is not how natural selection works.  Adaptations come online during the developmental phase in which they are needed – they develop reliably in all or most members of a species during the appropriate developmental state of an organism’s life.

• Evolution (EP) does not imply that behavior is genetically determined.
  Evolutionary psychologists believe that everything in the mind, body, and brain is co-determined by genes and the environment.  Environmental pressures drive the evolution of adaptations, and adaptations require environmental input to develop correctly during an organism’s lifespan.  Environmental triggers are necessary to activate the adaptation in the present.  All adaptations have a genetic basis but are not genetically determined.  Genes often build different minds in response to different environments.

  Different environments will change the way the mind causes behavior.   Thus, evolutionary psychologists accept that it is possible to change most human behavior. This flexibility is an essential part of how we are designed.  Natural selection has programmed human development to be contingent on various environmental triggers.

  “However, humans are not infinitely flexible.  Changes in the environment still interact with a relatively stable genome and a relatively fixed mental architecture.  We can’t make people fly just by giving them plastic wings” (Evans, D. & Zarate, O., 2005, p. 161).

• EP does not suggest behavior will be uniform across cultures; it suggests the neurocognitive machinery that produces behavior will be uniform across cultures.
  Natural selection has sculpted a universal ability to learn language, but the language learned depends on where a person grows up.  “Evoked culture” refers to cultural differences between groups that arise from combining a universal psychological mechanism with environmental inputs that differ across cultures.  Cultural differences in mating strategy demonstrate this by responding to a particular operational sex ratio in the local environment.   Evolutionary approaches to psychology predict cross-cultural universality at the level of information processing mechanisms, not at the level of behavior.  Again, this is called the “dual inheritance” model of human evolution, illustrating how we are “structured prior to experience.”

• EP does not think everything is an adaptation.
  Evolution also yields “byproducts” (spandrels) and “noise.”  Examples of byproducts include racism, sexual fetishism among men, homicide, uxoricide (killing a wife), and filicide (killing a son or daughter), religion and belief in the supernatural.  Evolutionary biology uses the term “spandrel” for features of an organism arising as byproducts rather than adaptations that have no clear benefit for the organism’s fitness and survival.

  Evolutionary psychologists accept that much of human behavior is a side-effect of modules designed for other things.  Some authors believe that the great products of human civilization — including art, religion, and science, are side-effects of modules originally designed for other purposes.  However, Geoffrey Miller (The Mating Mind, 2000) and most evolutionary psychologists now say that capacities for creative expression are, in fact, essential modules, or primary adaptations inside the global adaptation of sexual selection.

• EP does address individual difference.
  Although evolutionary psychology began with studying universal and sex-typical mechanisms, the last twenty years have produced a plenitude of research on individual differences related to personality characteristics, sexual jealousy, disgust, mating strategies, and within-sex variation, to name a few.

• EP does not assert that what is true ought to be true (the “naturalistic fallacy”).
  Evolutionary psychologists attempt to describe what human nature is like, not prescribe what humans should do.  They argue that discoveries of EP could be used to inform left-wing policies just as much, if not more than right-wing policies.  For example, the equal distribution of wealth could be advocated for by knowing that humans are adapted to live in groups in which inequality is relatively low.  EP does not make moral or value judgments. 

• EP does not believe in or promote eugenics.
  EP does not believe in selective breeding or optimizing the gene pool.  (Do I have to say this?) EP is focused on human behavior as shaped to optimize an individual’s chances of reproduction with no regard for saving the species.  Natural selection happens at the level of the individual organism.  Eugenics is a group-selection doctrine.  But finding mates with good genes is indeed one of the significant functions of mate choice across all sexually reproducing species.

• EP does not use questionable research methodology – it is not “just-so stories.”
  “Just-so storytelling” refers to the process by which a researcher notices something about human behavior, proposes an explanation for it (an evolutionary one in this case), and then decides to believe that explanation without further inquiry or testing.  This criticism asserts EP over-applies evolutionary explanations and that there are no safeguards against such over-application.  But, it is a misconception that evolutionary psychologists will take any finding and mold it into an evolutionary explanation after the fact.

• Evolutionary psychology (EP) is not simply a sub-discipline of psychology.
  Evolutionary theory integrates the life sciences and unites many disciplines.  Thus, modern evolutionary theory provides a foundational, meta-theoretical framework that integrates the entire field of psychology.  EP draws insights from anthropology, economics, computer science, and paleo-archaeology but relies mostly on the combination of evolutionary biology and cognitive psychology.

References

Buss, D.M. (1999). Evolutionary Psychology, The New Science of Mind.

Buss, D.M., & von Hippel, W. (2018). Psychological Barriers to Evolutionary Psychology: Ideological Bias and Coalitional Adaptations.  Archives of Scientific Psychology, 6(1) 148-158.

Evans, D., & Zarate, O., (2005).  Introducing Evolutionary Psychology.

Geher, G. (2014).  Evolutionary Psychology 101.

Mackiel, A. (2019) What Explains the Resistance to Evolutionary Psychology?  Quilette (April 8).