My best friend and I were talking about the human need to belong to groups. We found ourselves at a dead end when confronted with the paradox of social identity. The paradox of social identity can be broadly defined as “the tension between the need to belong to a group and the need to stand out as an individual.”
That led me to wonder, what makes humans need to belong? Or, in some cases, not belong?
To answer this question, I think it’s only fair to look back—to the human foundation, to the beginning of life, and to those who came before us: the animals. Alongside that, we must consider the human brain and psychology, and finally, contemporary culture.
First of all, it’s necessary to understand that all animal behavior is rooted in and shaped by survival. Behind every pattern of movement — the migrating bird, the resting lion, the fish swimming in schools — lies an invisible logic molded by instinct and the surrounding environment. Animals don’t freely choose to act as they do, mainly because they lack the same sense of judgment we possess. Instead, their behavior is shaped by the need for food, the threat of predators, the availability of shelter, reproductive cycles, and natural selection.
According to Charles Darwin in The Origin of Species (1859), the animal brain was shaped not by will, but by survival. In other words, an animal would never stop eating simply because it “doesn’t feel like it,” since such behavior would lead to death. There’s a fundamental difference between will and instinct — animals, by design, are biologically wired to follow instinct.
As Bear, Connors & Paradiso state in Neuroscience: Exploring the Brain (2015), the parts of the brain responsible for animal behavior are the limbic system and the brainstem — let’s call these the instinctive brain. Meanwhile, in humans, willpower is primarily associated with the prefrontal cortex — the brain of intention.
Just as animals evolved to live either in groups or in solitude, so did we. The development of language, empathy, and facial and bodily expression arose from group cooperation for survival. This is why animals that live in groups generally have relatively larger brains (especially the neocortex), as they must navigate complex social structures, whereas solitary animals rely on individual instincts.
To distinguish solitary from social animals, we must consider factors such as territory, resources, roles, defense against predators, and reproduction.
Collective behavior first emerged among insects about 100 to 65 million years ago. Ants, for instance, are believed to have become social at least 92 million years ago, supported by fossil records and genetic analyses.
Social animals like wolves, bees, dolphins, and elephants have greater chances of survival in groups, as cooperation increases protection from predators and allows for division of roles (leadership, hunting, vigilance, and caregiving), benefiting the entire group. On the other hand, solitary animals — such as octopuses, rhinoceroses, bears, and pandas — tend to adopt this lifestyle because resources are scarcer, and sharing food or duties would be disadvantageous. The only moment of union typically occurs during mating, after which they go their separate ways.
With that foundation, we can begin to analyze human beings, now having a clearer picture of how and why group behavior emerged in the animal world — survival.
The first hominids, around seven million years ago (species such as Sahelanthropus tchadensis, later Australopithecus), were still very close to chimpanzees and lived in small family tribes, whose main advantage was protection from predators.
Homo habilis, about 2.5 million years ago, had a cranial capacity of around 600 cm³ and organized into groups for simple hunting and carcass sharing, improving food efficiency.
The first species to leave Africa and discover fire was Homo erectus, around 1.8 million years ago, with a cranial capacity of about 900 cm³. Their social behavior revolved around communal fires, division of labor, and prolonged child care, providing greater safety, warmth, and cooked food — which, in turn, fueled brain development. This species was one of the most influential for modern society, especially with the discovery and use of fire as a tool for defense, hunting, and heat.
Furthermore, studies indicate that our hominid ancestors, such as Homo erectus, already possessed some form of communication, though not the articulated language we know today.
Homo heidelbergensis appeared about 400,000 years ago. This species was also important because it marked the beginning of the use of heavy tools, such as spears for hunting. Individuals gathered in groups of 20 to 40 to conduct organized hunts — hunting in groups ensured access to large prey, and the sharing of meat strengthened alliances.
From 200,000 to 40,000 years ago, the dominant species were the Neanderthals and archaic Homo sapiens. The Neanderthals, who lived between 200,000 and 40,000 years ago, already showed signs of living in small groups, caring for one another, and even burying their dead — evidence of emotional bonds and collective respect. With the emergence of Homo sapiens, around 200,000 years ago, brain volume increased to between 1,300 and 1,500 cm³, allowing for greater communication, planning, and cooperation. These advancements enabled larger, more organized groups.
By around 70,000 years ago, humanity began to create cave art, make ornaments, and perform collective rituals — marking the beginning of what we now call symbolic cohesion: the ability to share narratives, beliefs, and meanings.
