Is It Surprising That Our Brains Respond More to Those We’re Close With Than Those Similar to Us?

Unsurprisingly, both yes and no.

The reason it is surprising has to do with precedent. A recent and intriguing hypothesis in social neuroscience is that we understand others through the process of simulation. In one form, this would posit a mirror neuron-like process in which we activate "self-responsive" regions—brain regions that become active when we think about ourselves—in order to make predictions about others. However, simulation is only a good strategy if you and I are actually similar to each other. After all, why would I pattern your inner world after my own if you’re really nothing like me? This notion resonated with many classical social psychologists, especially those who study social biases like stereotyping. After all, it has long been known that we tend to prioritize people we’re similar to, even if similarity is assessed along what should be a totally inessential dimension. Perhaps the brain’s fundamental organization reflects these types of biases.

However, our results are unsurprising from a different perspective—namely, one that considers the pressures that would have shaped representational systems in social animals such as us. The strong form of this theory proposes that a critical event in the evolution of anthropoid species was the emergence of the capacity to create and maintain relationships beyond reproductive partners. We were intrigued by this idea because it seemed to us that the ability to recognize and assign value to relevant individuals within someone’s clan is incredibly important for maintaining group cohesion. What do I care that you are similar to me if what I really need to know is whether you are part of my tribe, friend or foe, above or below me in the pecking order? And if I do know you, why would I use myself as a proxy when I can instead draw upon my past experience with you to form opinions about what you’re like?

So I have to admit that we weren’t very surprised when we found that the brain responds to our friends in the same way regardless of whether they are similar to us, and furthermore, that this pattern of activity overlaps the pattern evoked when we think about ourselves. It actually makes us wonder how useful the concept of a “self” as somehow distinct and separate from the significant, varied relationships that broaden our views of ourselves and the world truly is.

Fenna Krienen is a doctoral student in psychology and the Center for Brain Science at Harvard University.