Methods for Testing Evolutionary Hypotheses

When we talk about science, we talk about theories, statistics, methodologies, and what is now. We are familiar with psychological testing and how different approaches are utilized to arrive at a conjecture. In a similar vein operates, all scientific fields and their theories.

Methods for Testing Evolutionary Hypotheses

After certain assumptions about evolved psychological systems and the corresponding expectations are developed, they must be investigated to understand and comprehend them. Evolutionary psychologists can use a wide range of scientific techniques. The scientific basis of evolutionary psychology is not based on a single methodology, instead relying on converging evidence from various methodologies and information sources.

  • Compare different species

  • Cross-cultural methods

  • Physiological and brain imaging methods

  • Genetic methods

  • Compare males and females

  • Compare individuals within a species

  • Compare the same individuals in different contexts

  • Experimental methods

The various methodologies can only be utilized when we have information that can be obtained from the following sources.

  • Archeological records

  • Data from hunter-gatherer societies

  • Observations

  • Self-reports

  • Life-history data and public records

  • Human products

Comparison of Several Species

One way to evaluate functional hypotheses is to compare organisms that vary across standard specifications. According to the comparative technique, "checking hypotheses regarding the trait's occurrence across organisms apart from the animals whose behavior the researcher attempts to comprehend is included. Comparing sperm competitiveness and testicular volume between various species is one way.

Additionally, we can contrast entities known to experience one adaptation difficulty with those known to experience another. The idea that sheep that forage on mountains will have technical modifications to avoid slipping, such as more vital spatial reasoning ability, can be tested by comparing cliff-dwelling sheep and non-cliff-dwelling sheep.

To test the theory that specific adaptations have been made to fend off those predators (such as specialized alarm cries made when meeting a picture of the predator), we can compare animals with recognized competitors with those missing those predators. In conclusion, comparing various species is an effective way to evaluate theories about how adaptation works.

Cross-Cultural Methods

Methods that span cultural boundaries offer valuable resources for evaluating evolutionary psychology ideas. The most transparent approach involves adaptations that are thought to be universal, including fundamental emotions, cooperative adaptations, or sex-specific mating tactics. Examining modifications allegedly made in response to various ecologies can also be done by contrasting various cultures. It has been demonstrated in a survey of 37 cultures that mate choices, for instance, are sensitive to ecological differences in parasite incidence.

Competing hypotheses can also be tested by being pitted against one another using cross-cultural approaches. Researchers investigated gender disparities in a mental rotation task spanning 53 civilizations. Because hunters must predict the arcs of spears or other killing weapons as they traverse space to match the course of a fleeing animal, it has been theorized that mental rotation ability is indicative of a masculine hunting adaption.

On the other hand, social role theory postulates that psychological gender disparities result from the roles that various cultures place on people and, as a result, should disappear when sex equality rises. This cross-cultural study discovered two key findings −

  • The gender disparities in mental rotation capacity were ubiquitous across cultures, and

  • According to social role theory, the gendered inequalities were somewhat higher in cultures with more gender diversity.

In conclusion, cross-cultural approaches are beneficial for evaluating a variety of evolutionary hypotheses as well as for comparing conflicting ideas.

Physiological and Brain Imaging Methodologies

It is possible to evaluate phenomena like emotionality, sex drive, and stress using physiological approaches. These techniques may be employed to uncover the biological underpinnings of psychological adjustments and evaluate theories on the structural elements of those adaptations. One hypothesis examined was whether kids with stepparents would be more stressed out than kids with two biological parents.

It was shown that stepchildren did have higher cortisol levels than non-stepchildren—one of the main chemicals released when people feel stressed. Another study supported the idea that males in committed love relationships would have lower testosterone levels, one of the primary chemicals in mate rivalry. Another study discovered that having gorgeous women around enhanced men's testosterone ranges. In conclusion, physiological approaches are helpful for both testing adaptation-related hypotheses and determining the underlying causes of adaptations.

Functional magnetic resonance imaging (fMRI), one type of brain imaging technology, is utilized more frequently to test theories on adaptations and underlying brain mechanisms. FMRI approaches have been utilized to investigate ideas about modifications for kin identification, linguistics, spatial awareness, amorous desire, and jealousy.

The use of brain imaging tools to test evolutionary psychological concepts has grown significantly over the past ten years, even though the spectrum of occurrences they may study is limited. Research participants must stay stationary while being subjected to stimuli.

Genetic Methods

Several evolutionarily based ideas can be tested using conventional behavioral genetic techniques, like twin studies and adoptees. One evolutionary theory, for instance, contends that females have a context-dependent adaptation that causes them to shift towards an earlier onset of sexuality and menarche when raising children without an investing father present, as opposed to a later onset of sexuality when an investing father is present. Behavioral genetic techniques can establish whether individual variations in the timing of female sexuality are biologically controlled, which would contradict the evolutionary hypothesis or contextually ameliorated, as the evolutionary supposition predicts.

More current techniques involve molecular genetics. They are made to find the precise genes responsible for the supposed adaptations. The evolution of humans has also been fascinatingly studied using molecular genetic techniques.

Comparing Males and Females

Male and female reproductive forms are typically present in sexually reproducing animals. Another way to investigate adaptation-related ideas is to compare the sexes. Analyzing the differences between the adaptive issues that males and females experience is one comparative technique. For instance, in species where females fertilize themselves internally, men must deal with the adaptive challenge of "paternity ambiguity." They will never be able to "know" for sure if they are the biological father of their partner's children.

Nevertheless, this adaptation challenge does not exist for females. They "know" that since the eggs can only originate from within them, they are the ones who are fertilized, not a rival's eggs. This research lets us contrast males and females to determine whether males have developed specific characteristics that increase their likelihood of paternity. Thus, it is another exemplary method to test a hypothesis.

Comparing Individuals Within a Species

Contrasting some people with others of the same species is the third technique. Think about women our age and older. Women in their 30s have limited reproductive years left, whereas teenage girls have several years of viable reproduction. These variations can be used to create and evaluate theories on adaptation. We predicted that younger women are more likely than older ones to abort a growing fetus without a supportive partner.

According to the evolutionary theory, younger women may "afford" to forgo the opportunity to become pregnant to wait for a more advantageous period to reproduce because they still have much fertile age left. The older woman might not have another opportunity to become a mother. One way to test this theory is to compare the incidence of abortion, stillbirth, and homicide in the two categories of women.

Comparing the Same Individuals in Different Contexts

A powerful technique for discovering developed psychological systems is contrasting the same people under different circumstances. It is possible to establish hypotheses about the adaptive challenges faced in two distinct circumstances and the psychological processes engaged in each. Unfortunately, it can be challenging for investigators to wait till a user moves contexts. Many people settle into a specialty and stick with it.

Additionally, even when individuals differ in their circumstances, many often change in one go, posing problems for researchers to pinpoint the precise cause of a change. Scientists occasionally attempt to "control" the environment in psychological tests due to difficulty isolating the precise causative elements at fault.

Experimental Methods

A "manipulation" is often applied to one set of test subjects in trials, while the other group acts as the "control." Suppose we have a theory about how threat affects how tightly "in-group cohesion" is held together. According to the theory, humans have developed a specific psychological process that aims to respond appropriately to external threats, like an incursion by a belligerent population.

Group cohesion should rise in times of threat, as seen by inclinations like partiality for members of the same group and an upsurge in bias towards members of other groups. We organize two groups – a control group and an experimental group and assign separate tasks to them. We would infer that our prediction was incorrect if both groups were identical.

In conclusion, adaptation-related theories can be tested using the experimental technique, which involves putting several groups in various settings (also known as manipulations).


Overall, it has been identified that a single methodology yields far less viable foundations than using a mixed method approach yields. The strength lies in applying the correct methodology in the correct context and then using that data to create new knowledge, support existing conceptualizations or build imaginations.

Updated on: 11-Apr-2023


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