Psychologists study people. Many psychologists have studied other animals, especially rats. But psychologists have never shown much interest in studying trees. Why not?
Trees, like people and all other living creatures, need to get certain things (e.g., water, nutrients) from the world around them. What is inside them is there to enable them to get what they need. The inside parts of trees enable them to draw water from the soil, chemicals from sunlight, and so forth. Trees, however, do not move around in search of food or to escape from predators. They take what comes to them where they are. Facing few decisions and being therefore essentially indifferent to other trees, they do not have much psychology. They don’t have much in the way of thoughts, feelings, or behavior, because they don’t need these things to survive and reproduce. (That’s why psychologists don’t find them interesting.)
Contrast this with animals who also live as loners. They have to find food, possibly kill it, and eat it. They need more food and produce more waste than trees do. They need to sleep and so must find safe places to do so. Reproduction is more complicated than it is for trees, so they may need to perform a particular set of behaviors in order to reproduce. Like trees, they need to interact with their world, but doing so is more complicated for animals, so what is inside them has to be up to the task. Psychologists start to get interested in these processes.
Many animals are not loners. They discovered, or perhaps nature discovered for them, that by living and working together, they could interact with the world more effectively. For example, if an animal hunts for food by itself, it can only catch, kill, and eat animals much smaller than itself—but if animals band together in a group, they can catch and kill animals bigger than they are. A pack of wolves can kill a horse, which can feed the group very well. Thus, there is more food available to the same animals in the same forest if they work together than if they work alone. There are other benefits of cooperation: They can alert each other to danger, can find more food (if they search separately and then follow the ones who succeed in finding food), and can even provide some care to those who are sick and injured. Mating and reproduction are also easier if the animals live in a group than if they live far apart.
In short, being social provides benefits. Being social is a strategy that enables some animals to survive and reproduce effectively. That is the biological starting point of social psychology: Being social improves survival and reproduction.
Th e downside of being social is that it is more difficult to achieve than solitary life. As with trees, what is inside social animals is there to enable them to get what they need from the environment. But to be social, one has to have quite a bit going on inside. (Hence psychologists can find much to study.) Social animals have to have something inside them that makes them recognize each other and want to be together. They must have something that prompts them to work together, such as automatic impulses to copy what the others are doing. (Hunting in groups doesn’t happen by mere coincidence.) They must have ways to resolve the conflicts that inevitably arise in social life, as when two animals both want the same piece of food. They need something akin to self-control to enable them to adjust to group life. In short, social animals need complex, powerful brains.
