Encyclopedia of Evolutionary Psychological Science

Living Edition
| Editors: Todd K. Shackelford, Viviana A. Weekes-Shackelford

How Evolutionary Psychology Can Still Explain Behavior

  • Richard HollerEmail author
  • Lauren Smith
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-16999-6_414-1



The understanding of foundations of psychology in respect to biology and of evolutionary psychology’s ability to coalesce various academic domains that advances the modern science of psychology.


The battle between nature and nurture continues to be incessant within the social science communities. Evolutionary psychology, however, is a field that takes initiative to become an exemplar of academic consilience. The inception of psychology and biology itself segregates themselves from the other, which distorts the perspective that behavior can be adaptations like physicality. Humans are organisms that possess brains that abide to the laws of evolutionary biology. Societies similar to modern Western ones exploit the operations of psychology as well as the ancestral conditions in which psychology evolved. When the comparisons between ancient and modern environments are established, evolutionary psychology will become a pertinence to the modern study of mind and behavior.

Psychological Attributes as Biological Adaptations

Like organisms, academic disciplines evolve. Psychology is widely accepted as a descendent of biology; however, parsing one from the other has resulted in academic complications and controversies. Behavior as an adaptation, sometimes called an instinct, serves as an intersection of psychology and biology. Behavior of all sorts rests on the foundations of the nervous system or the brain, which has and always will be subject to the principles of biological evolution.

Because the rates of both biological and cultural evolutions are far from identical, adaptations from exponential generations ago endure the journey to the contemporary generations. Like a biological adaptation, a psychological adaptation is a feature that ultimately enhances its genes reproductive fitness as a result of gradual modification generation to generation. Any adaptation or any seemingly designed characteristic is not always of service to the organism that possesses it. Mismatch theory posits that evolved features that were adaptive in certain environments are maladaptive in others (Buss 2015; Barkow et al. 1995).

Modern society and enduring cultures, intuitively, are distinct from one another; however, many, if not most, of them share similar qualities. Language, religion, sexual preferences, division of labor, and hierarchal structures, for example, are never identical culture to culture but certainly are in respect to their service to those who practice them. As a perspective of psychology, evolutionary psychology unites a variety of academic domains, which poses original questions on behavior. The lens of evolutionary psychology is capable of enlightening the current conundrums traditional psychologists frequently confront. As a truly integrative discipline, evolutionary psychology could contribute to the sciences of most, if not all, of the branches of psychology.

Psychology as a Descendent of Biology

The foundations of psychology lie within the nervous system. The central nervous system of modern humans or Homo sapiens is the brain, the hub of cognition and behavior. Like any organ, the brain is a product of gradual modification on the basis of evolution via natural selection. The accumulation of selective forces and environmental pressures that humans encountered throughout their evolutionary history ultimately forged, like any other biological entity, the brain (Palanza and Parmigiani 2016).

Distinction between the mind and body has been under debate since their inception. Science, today, advocates the dualistic view of the mind and body by delegating their studies into two different disciplines: psychology, which imperialized the study of mind and behavior, and biology, which imperialized the study of the body and its operations. This dualistic view yields unexplained discrepancies between neurological psychologists and molecular biologists. While every brain and mind is popularly believed to be different between every individual, merely every bodily aspect is inherited, including neurochemistry (Pervin 2009).

The terms psychology and biology themselves are a mean to their academic segregation. The underlying causes of mental illnesses and bodily diseases are almost indistinguishable from each other. The notion that psychological and biological principles are related is frequently condoned from both disciplines, yet one cannot survive without the other. As a descendent of psychology and biology, evolutionary psychology is the first scientific discipline that applies established biological principles to the study of human mind and behavior.

Life history theory predicts the pace of a species’ maturation when given its ancestral history and modern environments. Furthermore, life history theory can be used to predict characteristics such as lifespan and degree of social cohesion. Mental traits that foster socialization develop nonrandomly from species to species. Even major brain regions like the amygdala, hippocampus, and frontal lobes begin and finish developing during specific times of an organism’s lifespan (Figueredo et al. 2006).

Somatic effort, an organism’s pursuit for self-growth and maintenance, transforms into reproductive effort or the will to obtain the means to procreate. Reproductive effort may then evolve into mating effort to select a particular mate from a selection of potential mates, which may transform into parenting effort, which is an organism’s nature to bear and rear its offspring they can sustain themselves. The relationship from somatic to parenting efforts enables life history theory to predict the number of offspring typically reproduced, sex differences in mating strategies, years of adolescence, risk-taking tendencies, and even social deviance (Figueredo et al. 2006).

Sexual selection theory also has implications on the nature of parenting. Sexual selection is the preference of one sex to choose to mate with members of the opposite sex. Generations of sexual selection result in more unique characteristics that distinguish one sex from the other. Sexual selection influences almost all of the nuances of a species’ reproductive nature. Relative to males, females more often invest both more and a variety of efforts to the overall fitness of their young, especially within the mammalian kingdom. Evolutionary psychology endorses the relationship between sexual selection and parental investment theory as it provides new insights to explain human parenting and mating behavior (Buss 2015; Geher 2014).

Behavior or acts of expression may be viewed as a physical adaptation enhancer. Scientists within the domain of ethology effortlessly explain animal behavior from an evolutionary standpoint, yet the nature of biology is condoned when examining behavior of Homo sapiens. Physical structures that characterize an organism are designed by biological evolution (Cosmides and Tooby 1997; Palanza and Parmigiani 2016); the architecture of the brain changes in order to guide its host to survive without excessive discomfort.

Mental traits, like their physical counterparts, are adaptations. Behavior is a result of both genes and environments (Cosmides and Tooby 1997). From an ultimate perspective, the origins of behavior can be traced to the principles of biology. This perspective does not assert that every action or single behavior is of a survival or reproductive service; rather it posits that psychological phenomena are not completely dependent on experience and are partially inherited qualities from previous generations.

Evolutionary Mismatch Theory

Traditional social sciences have an extensive history of putting nurture before nature. This standard social science model (SSSM) originates from the false conception that mind and behavior is a product of only experience, which is also called the blank slate (Barkow et al. 1995; Figueredo et al. 2006). Given that numerous regions of the brain are functionally specific (Cosmides and Tooby 1997; Palanza and Parmigiani 2016), an adaptationist approach to psychology may be scientifically advantageous (Buss 2015; Barkow et al. 1995; Geher 2014). The SSSM significantly lacks this perspective, which transcends to a plethora of unasked questions.

It is necessary to reiterate that the rate of cultural evolution is far beyond the rate of biological evolution, for biologically complex organisms. The human brain’s evolution predominantly derives from when early humans were hunter-gatherers (Cosmides and Tooby 1997). The persistent problems human ancestors faced – droughts, famine, competitions for resources, predators, and disease, to name a few – serve as ultimate and unique selective pressures. Individuals with cognitive advantages over the others better adapt to evolutionary pressures over time. The more consistent the evolutionary pressures, the more time the mind has to specialize in each evolutionary hurdle (Buss 2015; Barkow et al. 1995; Geher 2014).

The position that human psychology is chronologically displaced due to the rapid rate of change of culture and society leads evolutionary psychologists to espouse evolutionary mismatch theory. A psychological trait is either an adaptation, a by-product of other adaptations, or a random effect (Buss 2015). A central theme of evolutionary mismatch theory is that an adaptation is not always adaptive or maladaptive (Caporael 2001). Evolutionary psychological theories and hypotheses frequently result from this popular theory, many of which assist the field to explain contemporary psychological phenomena.

A lucid example of mismatch is the penchant for sugary and fatty foods. Hunter-gatherers would not be called hunter-gatherers if there were a McDonalds or a supermarket in their environments. The conditions hunter-gatherers evolved from had a dearth of food and nutrition. Humans who yearn and seek for fatty foods have advantage over those without it or those with a lesser degree of it. Today in developed nations, fast-food restaurants and supermarkets are ubiquitous, which result in maladaptive responses, such as heart disease, high cholesterol, and obesity (Geher 2014).

Modified pictures and popular movies with slim women and men have significant influence on its audiences. Teenagers and young adults prioritize their physical appearance so high that they become malnourished or spend masses of money for unnecessary surgeries. Both the absence of images of slim women and men throughout Homo sapiens’ evolutionary history and the social-behavioral phenomenon to imitate individuals with seemingly desirable traits exploit humans’ evolutionary mismatch of environments (Ferguson et al. 2011).

Evolutionary mismatch theory may also explain the rise of the epidemic of clinical depression. Evolutionary psychologist, Stephen Ilardi, advocates for a lifestyle similar to those of earlier humans. Actively participating in social relationships, getting daily exercise with a diet similar to the Paleolithic diet, being awake and outside in broad daylight while maintaining a proper sleep schedule, and being mentally engaged to minimize rumination comprise Ilardi’s new therapeutic regime. Healthy diets, proper exercise and sleep, exposure to sunlight, and living in the present moment are painstakingly difficult to obtain in modern developed nations. The vast majority of clinically depressed individuals who participated in Ilardi’s program reported to have obtained an overwhelming degree of success and recovery without the use of antidepressants (Ilardi 2010).

Although there are cogent instances of evolutionary mismatch when comparing the ancestral environments with those of developed nations, social scientists urge evolutionary psychologists to demonstrate the phenomenon in all nations and cultures. Universal behavior across independent cultures would elucidate evolutionary psychology’s role on modern behavior.

Any two cultures are far from identical, but the variations between them are not completely random (Schmitt et al. 2016). Evolutionary psychology with the cultural and multicultural psychology perspectives provides viable predictions within esoteric cultures. Women with a waist-to-hip ratio of .7, for example, is rated as the most attractive by men from both developed nations and indigenous tribes (Singh and Young 1995; Buss 2015; Schmitt et al. 2016), which bolsters the hypothesis of universal behavior as evidence for a biologically evolved psychology.

Evolutionary Psychology and the Subdisciplines of Psychology

Any mental capacity or ability that survives and is passed down to the next generation, one way or another, is technically an evolved psychology. Evolutionary anthropologists and psychologists claim that human psychology is derived from early humans as hunter-gatherers (Cosmides and Tooby 1997), and despite that it was designed for prehistoric environments, it survived or adapted to modern environments. More simply, modern psychology is prehistoric psychology “but on steroids” (Pinker 2011).

Stimuli from contemporary cultures and environments act on the same biological frameworks that stimuli from ancient cultures and environments did. The difference between how the mind operated and functioned in hunter-gatherers and how it operates and functions in modern human beings is not due to a biological change; it is due to an environmental and cultural one. Reading, going to school, and living in large cities are examples of evolutionary novelties. Although many novelties engender admirable behaviors, many yield abominable ones.

It is a common misconception to view evolutionary psychology as a justification for malicious or any sort of behavior. Individuals who support this naturalistic fallacy fail to recognize that the study of evolutionary psychology can provide powerful insight of how to proactively control unwanted behaviors (Wilson et al. 2003). With the understanding of any complex system, one can do more than just control unwanted behaviors. The philosophy of evolutionary psychology can produce viable predictions of behavior within various branches of psychology. An adaptationist perspective will yield unasked questions that traditional psychologists neglect.

The modularity hypothesis, the position that the brain is like a computer with programs that are installed for various functions, is still at the center of debate within cognitive psychology. Evolutionary psychologists espouse the modularity hypothesis in a manner similar to why evolutionary biologists espouse that almost every characteristic of an organism specializes in a particular function (Cosmides and Tooby 1997). Certain cognitive traits and capacities develop at certain rates and are nonrandomly situated in specific locations of the brain (Caporael 2001). Cognitive traits do not arise from oblivion for no reason (Buss 2015; Barkow et al. 1995).

The cornerstone of human culture, language, is a truly universal attribute among Homo sapiens. A social species with the ability to express unlimited information can quickly dominate those without same ability. Evolutionary psychologists explain the origins of verbal language as an exaptation or by-product of human social nature and intelligence (Pinker 2010; Caporael 2001) that has transcended into an adaptation. Traditional cognitive psychology does not refute that language has a biological basis, but it does assert that the capabilities for verbal language are primarily obtained through practice. The controversial critical period, the time when humans are most prepared to acquire verbal language skills, suggests that language can only be learned within a human’s specific time window. With the fact that language is localized within Broca’s area, the region of the brain associated with human speech, evolutionary psychology sits at the forefront of investigating the biological bases of verbal language (Pinker 2010).

Social psychology is a prime disciple of the SSSM. Cultural and social psychologists frequently claim that cultural norms and experience strictly shape human psychology; however, culture is not an adequate explanation for behavior. Moreover, explicating behavior via culture may be a redundant and even a stalling explanation (Barkow et al. 1995). Social psychology supports that committing altruistic acts are strictly motivated by intrinsic satisfactions. Ethology and evolutionary psychology, on the other hand, well explain and predict the instances of altruistic behavior.

Kin-selected altruism rests on evolutionary biological principles that can be observed in many nonhuman species. From a gene’s perspective, putting oneself in harm’s way in situations where the gene can continue to survive via its host’s biological relatives sheds light on the unconditional nurture between biologically related organisms (Geher 2014). In low-risk or low-cost situations, humans are more likely to act altruistically toward friends, which can be reciprocated, whereas humans in high-cost situations are more likely to help their kin or family (Stewart-Williams 2007).

Life history theory may ultimately predict the development of the brain maturity and certain mental abilities (Figueredo et al. 2006), which is also subject to the study of developmental psychology. The onset of puberty and the relationship between infant mobility and fear of heights suggest that both bodily and mental changes are not completely random (Swanepoel et al. 2016). Applying life history theory, a biological evolutionary theory, to developmental psychology may help social scientists learn when and how to intervene various behaviors.

Attachment is fundamental to the development of healthy social relationships. Both traditional and evolutionary developmental psychologists stress the importance of establishing interpersonal relationships on one’s well-being and fitness. Renowned scientist, John Bowlby, examined the functions of the development of an unconditional attachment between an infant and caregiver. Bowlby (1982) recognized that many primates and mammals evolved behavioral-motivation systems to have both their physical and emotional needs met by a caregiver (Palanza and Parmigiani 2016). If these needs are met, individuals will develop a healthy and secure attachment style toward others; if not, individuals are likely to develop an insecure attachment style that could lead to severe issues within subsequent social and personal relationships.

Evolutionary psychology can also contribute to the field of personality psychology. Each of the Big Five personality traits (openness, conscientiousness, extraversion, agreeableness, and neuroticism) can be portrayed as a behavioral adaptation. Evolutionary theory hypothesizes that extraversion is rated as more attractive than introversion (Nettle and Clegg 2008). Not only was the hypothesis supported; it was also found that the more extraverted an individual reports to be, the more sexual partners that individual is likely to have (Buss 2015). Beyond personality traits, evolutionary psychology traces self-esteem, subjective well-being, and mental disabilities to their origins and uses. Additionally, the variation of personality characteristics across cultures is not due to chance, but is due to the environmental conditions (Schmitt et al. 2016).

Treating mental disorders like anxiety and depression is incredibly rare in indigenous tribes that are independent from other cultures, whereas developed societies treat mental disorders on a daily basis (Ilardi 2010). Evolutionary psychology poses unprecedented questions that gravitate around a variant of functionalism. Mania and periods of low energy and activity fluctuate with the four seasons, which is a relationship that cannot be depicted without the evolutionary lens (Geher 2014). Most, if not all, psychiatric disorders are considered to be results of the mismatch between ancestral and modern environments. Clinical depression, among other mental illnesses, is now under immense scrutiny since the evolutionary perspective advanced depression treatments within clinical psychology (Buss 2015; Palanza and Parmigiani 2016; Ilardi 2010).


Psychology is, in a perspective, a branch of biology; however, psychologists and biologists are reluctant to inspect phenomena from the other domains. Established theories of evolutionary biology, such as sexual selection and life history theory, indirectly influence behaviors that take advantage of physical attributes and abilities. While the brain shelters the human soul, it abides by the laws of biological evolution.

Although cultural evolution complicates the means to observe evolved behavioral adaptations, by-products, and random effects, evolutionary mismatch theory disambiguates one from the others. Modern tools and technology facilitate many endeavors, yet their consequences accumulate to a seemingly incessant burden. Human psychology evolved from humans with the predominant occupation of hunting and gathering, yet the once adaptive traits betray our physical and mental health today. Whether or not culture is responsible for one’s actions, it is not a cogent explanation of behavior.

Universal behavior across modern and indigenous cultures, like mating preferences and social altruism, is an evident support for psychology possessing a heritage. Despite that evolutionary psychology is mistakenly accused for justifying unwanted behavior, it has made prominent advances in cognitive, social, developmental, personality, and clinical psychology. With the adaptationist frame of mind that can be applied to, perhaps, all psychologies, evolutionary psychology cannot be sufficiently identified as a subdiscipline of psychology. Given that psychology is a descendent of biology, evolutionary psychology is not an opposition of traditional psychology; it is a missing property of the study of mind and behavior, psychology.



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© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.State University of New York at New PaltzNew PaltzUSA

Section editors and affiliations

  • Haley Dillon
    • 1
  1. 1.Dominican CollegeOrangeburgUSA