How Evolution Brought The Factor of Emotion into Human Lifestyle

Human emotion is a subject many find too complex to fully understand. Humans feel such a variety of different emotions and it can be difficult to explain the reasoning and purpose of each one. The research question that will be discussed is: How has evolution brought the factor of emotion into human lifestyle?

The first dive into the idea of evolutionary emotion was from Charles Darwin himself. Darwin wrote a book entitled “The expressions of the Emotions in Man and Animals,” and in it, he provided the first theory of evolutionary emotion. Darwin spoke about how emotions were heritable in humans and not just learned as we grew in society. The two main purposes he believed emotions had were to aid in survival and communication with other creatures. An example of survival aid is how fear drives the human body to become more precise with certain senses to aid in a way to escape. The idea of emotions aiding in communication is based off of the observation that humans can recognise different emotions in each other and in other animals, and the same goes for other living creatures.

Darwin described emotion with three different principles. The first is that beneficial habits strengthen over time such as the emotion disgust. Disgust aids in the avoidance of things that may be poisonous or harmful to one’s body. The second explains that opposite situations of ones a habit has been already formed around will result in opposite reactions. The third is that there can be an accumulation of energy in the nervous system that is released as a certain behavior. This happens involuntarily and Darwin referred to it as a “nervous discharge.” Darwin supported his theory of evolutionary emotion through two main examples. The first is the example of newborn babies. On birth, newborn babies cry and express other vital emotions, and even in babies that are born blind, they still show the same vital emotions including the behavioral response of seeing an individual. The second example is the one based around the idea that different creatures can instinctively recognise certain emotions in others.

The process of how emotions occur in our brain is difficult to explain. In a paper written about the evolution of human emotion, Joseph E. LeDoux, an American neuroscientist states: “First came “primitive” cortical regions in early mammals. In these organisms the basic survival functions related to feeding, defense and procreation were taken care of by fairly undifferentiated (weakly laminated) cortical regions (primitive cortex, including the hippocampus and cingulate cortex) and related subcortical areas (such as the amygdala) that were closely tied to the olfactory system. Later mammals added highly novel, laminated cortical regions (neocortex) that made possible enhanced non-olfactory sensory processing and cognitive functions (including learning and memory, reasoning, and planning capacities, and, in humans, language).” An example used many times to explain how emotions work is fear, and an explanation for how fear occurs in the brain is provided by LeDoux. “As mentioned already, Pavlovian conditioning is the initial phase of avoidance conditioning. After the subjects rapidly undergo Pavlovian conditioning, they then slowly learn to perform avoidance responses using the CS as a warning signal… In Pavlovian fear conditioning, the subject receives a neutral conditioned stimulus (CS), usually a tone, followed by an aversive unconditioned stimulus (US), typically footshock. After one or at most a few pairings, the CS comes to elicit innate emotional responses that naturally occur in the presence of threatening stimuli, such as predators.”

Leda Cosmides and John Tooby, pioneers in the idea of evolutionary emotion state that “[emotion] is the statistical composite of selection pressures that cause the genes underlying the design of an adaptation to increase in frequency until they become species-typical or stably persistent.” and “modes of operation or an orchestration of all the different mechanisms; turning some off, turning some on, in particular situations, which are particularly well-designed to deal with the challenges of given situation.” They describe how emotions are like programs that help in the resolve of evolutionary issues. These programs are triggered by signals sent out when different situations occur. Cosmides and Tooby also use the example of fear in their explanation. The situation of being in the presence of a predator will send a signal that activates the fear program in the brain. This program is meant to help solve the situation by changing the brain’s current motives, prioritizing functions in the body at the given moment and changing the sensitivity of certain senses. Almost all the features of psychology can be altered by different emotional states. These states slightly change certain psychological features in order to access a mode of that feature that, through evolutionary adaptation, is the “best bet” to be able to help solve the situation.

The conditions or situations relevant to the emotions are those that (1) recurred ancestrally; (2) could not be negotiated successfully unless there was a superordinate level of program coordination (i.e., circumstances in which the independent operation of programs caused no conflicts would not have selected for an emotion program, and would lead to emotionally neutral states of mind); (3) had a rich and reliable repeated structure; (4) had recognizable cues signaling their presence; and (5) in which an error would have resulted in large fitness costs.

Because of the different roles played by chance and selection, the evolutionary process builds three different types of outcomes into organisms: (1) adaptations, that is, functional machinery built by selection (usually species-typical), (2) byproducts of adaptations, which are present in the design of organisms because they are causally coupled to traits that were selected for (usually species-typical), and (3) random noise, injected by mutation and other random processes (often not species-typical).

In a lecture given by June Gruber of Yale University, she describes the EEA, or the Environment of Evolutionary Adaptiveness, which is what helps us understand the true reasons why emotions were needed and why they came along in lives of early hominids. Hunter and gatherer societies that still exist today were studied to help understand why humans needed to evolve emotion, and properties of the EEA were revealed. Five properties that Gruber speaks about are: the vulnerability of offspring, monogamous bonds, emergency of caring and compassion, flattening of social hierarchies, and need of collective action. Vulnerability of offspring is a common thing most animals; However, the offspring of humans is much more vulnerable. It can take years for the human brain to develop enough to even begin to understand things, while most other animals are leaving their mother to be on their own before that. Because of human offspring being so vulnerable, we have evolved the need of emotions such as nurture, love and compassion to be able to feel and care for them. Monogamous bonds refer to the long term relationships between humans. An instinctive priority in humans is the need to reproduce, and in order to complete that goal, emotions of needing a long term commitment to another human is needed in order to reproduce and help support the vulnerable offspring. Emergency of caring and compassion became important because of the need to care for young offspring and for older members of society. The flattening of social hierarchies is explained by humans’ innate need to have egalitarian societies, meaning that each member is treated equally. The need for collective action is important because many things humans do require collaborative efforts, and in order to satisfy to those needs, humans developed behaviors that assisted in becoming more cooperative.

The evolutionary approach to emotions includes five main ideas: gene replication, selection pressures, natural selection pressured, sexual selection pressures and group selection pressures. Gene replication talks about how certain genes are concentrated on more frequently to make sure they make it to the next generation. Selection pressures push or pull away at the chance of survival of certain genes. Natural selection pressures decide how likely an organism is to survive and reproduce. Sexual selection pressures push the ability to be able to reproduce. Lastly, group selection pressures describe how more cooperative members of society are more likely to survive and reproduce.

In recent studies of evolutionary emotion, even more specific groups of drives of emotion have been dug up. An article by Laith Al-Shawaf, Daniel Conroy-Beam, Kelly Asao, David M. Buss lists these groups. “This diverse range includes sexual consummation, intrasexual mate competition, mate retention, mate poaching, hierarchy negotiation, losses of status, gains of status, punishment of coalitional free-riders, retribution for social cost infliction, strategic interference, kin protection, kin investment, food acquisition, and others”.

The main ideas needed to summarize the evolution of emotions are all here: the original theories, why emotion came along, how emotion programs function in our brains, and how they have changed to help human society flourish. All of these studies, explanations, and pieces of evidence come together to explain the origin and evolution of emotion. Emotion is more deeply connected with psychological functions than was originally thought and ties in to almost all of our natural behaviors. It has been found that they aren’t just “feelings,” they are our brains’ ways of coping with certain situations and trying to solve each one. There is much more to know and learn about emotion, we just have to dig deeper.