Core of Human Nature: Fundamentals of Evolved Psychological Mechanisms

The essence of the masculine lion includes walking on four legs, developing a curly afro of fur, and engaging in food hunting. The butterfly's innate ability to transform into a flightless pupa condition, cocoon itself, and then emerge to soar and flit elegantly in pursuit of food and mates is inherent in its natural life cycle.

The ability to protect oneself with quills, a spritz, horns, or a carapace is ingrained in the character of the porcupine, skunk, stag, and turtle, respectively. Each species has a unique nature, which is present in all species. Each species has encountered a particular set of adaptive challenges since it has experienced somewhat different selection forces throughout its evolutionary history.

The Core of Human Nature

All psychological theories assume that humans also have natural—qualities that make us a distinct species. Sigmund Freud believed that raging sexual and violent impulses made up human nature. According to William James, dozens or thousands of instincts make up human nature. Even the staunchest ecological views presuppose that people have natural learning processes. Every psychological theory must start with some basic assumptions about human nature.

All theoretical approaches are either directly or indirectly evolutionary since evolution through selection constitutes the sole recognized causative mechanism capable of developing the core elements of that human nature. If evolution by choice is the process that created human nature and if people have a natural, the next issue is: What valuable insights into humankind may be gained from studying our evolutionary past?

The study of the human mind as a compendium of developed processes, the circumstances that stimulate those frameworks, and the behaviors produced by those mechanisms are the centerpiece of evolutionary psychology, as opposed to the more general field of evolutionary biology, which is preoccupied with the evolutionary assessment of all the integral elements of an organism. So, we are now turning directly to the category of evolved psychological mechanisms that comprise the human mind.

Definition of an Evolved Psychological Mechanism

An organism's internal processes with the following characteristics are considered to be an evolved psychological mechanism −

Exists in the form that it does because it solved a specific problem of survival or reproduction recurrently over evolutionary history.
Designed to take in only a narrow slice of information.
Input tells an organism the particular adaptive problem it is facing.
Input is transformed through decision rules into output.
Output can be physiological activity, information to other psychological mechanisms, or manifest behaviour.
Output of an evolved psychological mechanism is directed toward the solution to a specific adaptive problem

Solving Problems of Survival or Reproduction

An evolved cognitive system exists in the way it does since it repeatedly, during evolutionary history, addressed a particular challenge of survival or reproduction. As a result, the mechanism's shape and collection of features function like a key customized for a specific lock.

The geometric parameters of a psychological process should be shaped to suit the requirements necessary to address an adaptive issue of existence or replication, much as the form of the keys should be matched to meet the internal representation of the lock. Failing to solve the adaptive challenge meant failure to go through evolution's sifting process.

Process Data

An evolved psychological mechanism is built to process a limited amount of data. Think about the human eye. Although we can see almost anything when we open our eyes, the eye is only receptive to a small subset of electromagnetic waves, specifically those in the visible range. X-rays, which are smaller when compared to the optical range, are invisible to the human eye.

Nevertheless, even across the emission spectra, our eyes can only process a smaller fraction of data. Human eyes contain specialized edge detectors that identify opposing rays from surfaces and motion sensors that detect motion. Also, they have particular cones that are made to detect certain information about the hues of objects.

Hence, the eye cannot be considered universally capable of seeing. It is intended to handle a much smaller subset of the much more expansive possible information space, such as specific frequency ranges of waves, edges, movements, and so on.

Inputs about Adaptive Problems

An organism learns about the specific adaptive difficulty it is experiencing via the information of a developed psychological process. The input of spotting a snake in motion alerts us to a specific survival issue, specifically the risk of suffering physical harm and possibly death if bitten. We are dealing with an adaptive survival dilemma of food choice by the contrasting scents of potentially edible objects—rotting and rancid versus sweet and perfumed.

In a nutshell, the information informs the organism about its particular adaptive challenge. Almost always, this happens outside our consciousness. As a pizza is baking, people do not immediately think, "Aha! I have an issue with food selection due to adaptation! Instead, the smell triggers intuitive food selection mechanisms without awareness of the adaptation dilemma.

Transformation via Decision Rules

Decision rules convert an evolved psychological mechanism's input into output. When we see a snake, we can choose whether to attack it, flee from it, or pause. We can eat or ignore the pizza that has just come out of the oven. The "if, then" techniques in the decision rules direct an organism in one direction. Humans might have "if, then" rules such as: "If the furious rival is bigger and more powerful, then shun a fist altercation; if the angry competitor is weaker and more petite, then embrace the public invitation and fight."

When openly addressing an angry rival. In this example, decision rules ("if, then") translate inputs (a clash by an irate rival of a specific size) into outputs.


Physiological action, data to other psychological processes, or apparent behavior can result from an established psychological mechanism. We may feel physically excited or afraid when we see a snake (physiological production), use this data to evaluate our behavioral options, like freezing or retreating (data to other psychological processes), or take action by running away (behavioral output), depending on the evaluation.

Another illustration would be sexual jealousy. Consider attending a soiree with our significant other and leaving the event to have a drink. When we return, we see our partner engaging in animated conversation with someone else. We can see that they are softly caressing while standing near and gazing into one another's eyes. These cues may result in a feeling known as sexual jealousy. The cues communicate an adaptation issue—the risk of losing our partner—by acting as input to the process.

After then, this input is assessed using a set of decision-making guidelines. One alternative is to pretend to be unconcerned and disregard the two. Threatening the competitor is another choice. The third possibility is to hit our lover out of wrath. Reassessing our relationship would be another choice. As a result, a psychological mechanism's result could be behavioral or physiological or an intake into other psychological processes.

The output of Solving a Specific Adaptive Problem

An evolved psychological mechanism's output is focused on finding a specific signalling problem's solution. The outcome of the sexual envy circuit is directed at resolving the adaptive problem, just as cues to a partner's possible infidelity convey the issue's existence.

Our partner may stop flirting with other people, the threatened competitor may depart, or we may decide to end the relationship after giving it another look. These could aid in finding the answer to our adaptive dilemma. The fact that a psychological mechanism's output results in solutions to specific adaptive challenges does not guarantee that such solutions remain practical or ideal. Our warnings might not be enough to discourage the competitor.

Despite our jealousy, our companion might sleep with our rival. The key argument is that psychological mechanisms generally tend to solve adaptive problems more effectively than rival approaches in the contexts in which they developed, rather than that their outputs always result in successful solutions.


In conclusion, an evolved psychological mechanism is a collection of procedures within the organism created to absorb a specific piece of input and translate that knowledge into output via decision rules that historically have assisted with resolving an adaptive challenge.

The psychological mechanism can be found in living things since it, on average, helped their ancestors solve a particular adaptation problem. A crucial thing to remember is that a process that produced a good solution in the past might or might not produce one now.

Updated on: 11-Apr-2023


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