How Evolutionary Psychology Explains Human Behavior

Evolutionary psychology is a scientific discipline that approaches human cognition, emotions, and behavior through a lens that incorporates the effects of evolution over time. It combines two sciences, psychology and biology.

Based on Charles Darwin's ideas explained in his book, "Origin of Species," an organism’s main goal is to survive and reproduce and those organisms that adapted biologically to environmental changes were able to do both.

Similarly, evolutionary psychologists seek to explain how people made psychological adaptations in order to survive the dangers of the past which is the framework used to explain modern human behavior.

This article will describe how evolutionary psychologists explain modern human behavior as a product of the past, review the basic principles of evolutionary psychology, and apply these principles to the development of fear and phobias.

Evolutionary Psychology Approach

William James, the father of American psychology, was inspired by Darwin's theories of natural selection and sought to understand the purpose of mental processes and behaviors that have evolved over time to help humans adapt and survive. This became known as functionalism which defines mental states by their function.

Proponents of this psychological approach posit that our ancestors confronted problems and developed ways of solving them. Those who had more problem-solving skills would be more likely to survive. They gained important advantages, such as better health or a longer lifespan, allowing them to produce more offspring. Examples of these adaptive skills:

• process information
• solve problems
• communication skills
• express emotions
• identify others' intentions
• choose a healthy mate
• group cooperation

Other psychological adaptations to promote survival include the fight or flight response that is activated when we face a dangerous situation such as a predator or enemy. In addition, aggressive behaviors may have been necessary when people had to compete for resources or mates.

Hardwired for Survival

Evolutionary psychologists believe that these adaptive behaviors have become rooted in deeply complex neural circuits in the brain and that they are inherited by subsequent generations.

Although these innate behavioral tendencies are often tempered by input from our culture, family, and individual factors, the principles of evolutionary psychology suggest that the underlying neural mechanisms are shaped by evolutionary forces.

Principles of Evolutionary Psychology

Evolutionary psychology explains the behavior of humans today as a set of psychological adaptions that were made in order for our ancestors to survive in their environment. These adaptations are now hardwired into the human genome through the natural selection process, or the survival of the fittest, so to speak.

Below are some of the basic principles of evolutionary psychology that contribute to the nature of modern man:

• Your mind is based on adaptive changes that originated in the Pleistocene era (100,000 to 1.8 million years ago), giving modern humans the adaptions developed in a stone-aged mind.
• Your brain is an information-processing device that produces behavior in response to the environment. Your environment can be external (seeing a predator) and internal (feeling nauseous after eating).
• The specific ways that the neural circuitry is constructed in your brain today have been directed by natural selection from our ancestors who best solved problems, over the course of many generations millions of years ago.
• Most of your psychological processes take place subconsciously within your neural circuitry. You rely on conscious decision-making to guide you in your daily life, but you are unaware of the complex underlying process involved.
• Neural circuits in the brain are highly specialized to solve different adaptive problems for your survival. For example, the circuitry involved in vision (seeing predators) is not the same as for vomiting (eating something poisonous). 

Although many aspects of biological evolution are widely accepted among scientists, evolutionary psychology is a controversial field of study with much debate. One of the field's major criticisms is that the assumptions are not falsifiable because we do not truly know the intimate details of the psychological functioning of our stone-aged ancestors.

How Evolution Explains Fear and Phobias

Healthy Fear

Developmental psychologists explain that in normal infant development, there are a variety of hardwired reflexes that help newborns get through their most vulnerable months. They root, suck, grasp, and cry. They have a startle reaction called the moro reflex when they sense their head shifting position quickly (like a falling sensation), and they jump at loud noises.

Fear and disgust are two of the earliest basic emotions that emerge in babies, along with happiness, anger, surprise, and sadness. These emotions appear to be hardwired in the developing human, and an evolutionary psychologist would explain they are adaptive behaviors to assist in their survival. In other words, expressing these emotions is how they get their needs met and promotes bonding with their caregivers.

Around 6 months, babies develop a fear of strangers and this fear peaks when they are between 12-15 months old. They also develop a fear of heights between 6 and 10 months when they learn to crawl. An experiment demonstrated how babies refuse to crawl over a cliff (an illusion created by the experiment) even when their parent is coaxing them over the cliff.

Irrational Fear, Anxiety, and Phobias

It has been debated whether certain fears exhibited in young children are learned or innate. For example, research studies show you are more likely to fear snakes and spiders than other predatory animals, such as lions and tigers.

Babies who are less than six months old exhibit a fear response (pupils dilate) when they see a picture of a snake or spider, presumably before they have had a chance to learn this response from a bad experience or observing fear in others. It may be a combination of fear and disgust that creates this healthy fear response, one that helps us survive as infants.

From an evolutionary point of view, this may be due to the fact that snakes and spiders are more difficult to spot. It made sense to our ancestors to look carefully for poisonous creatures before sticking their hands into woodpiles or overgrown brush. Over time, that ability to recognize and quickly react to these small, quiet creatures became a trait that many humans inherited as an instinctive human reaction.

However, these mechanisms that are designed to help us survive can become problematic if we are responding with excessive fear to imaginary threats or stressors that are not life-threatening. An overactive fight or flight response can lead to mental health conditions such as anxiety, panic attacks, and phobias. Phobias are fears that are irrational and that go beyond protecting you from danger.