When we enter a room, we instantly assess who is dominant and who is submissive. This ability is fundamental to successful social cooperation, yet little has been known about the neural processes behind it. Researchers at ELTE and the University of Arizona were the first to discover how the brain encodes social hierarchy and how this influences visual attention by studying the brain activity of monkeys.

In order to navigate social environments, it is essential that we recognize the hierarchy among those around us. This determines who we observe more closely or whose gaze we follow. An international research team, including Hanga Dormán from the HUN-REN Research Centre for Natural Sciences and Zoltán Nádasdy from ELTE PPK, investigated the neurological mechanisms that facilitate this rapid and automatic decision-making.

What happens in the brain before a glance?

When we look around, our eyes do not scan the environment randomly, but make rapid, jerky movements called saccades. More and more research suggests that the sequence of fixations (when the eye stops briefly and focuses on a point) and saccades reflects not only what we are currently seeing, but also our previous experiences and the brain's predictions. In other words:

our eye movements reveal what we find relevant in a situation.

The researchers wanted to know how social status affects related neural activity in two key areas of the brain: the amygdala and the hippocampus.

Previous studies have shown that both areas are involved in recognizing social rank. Although the amygdala is often referred to as the center of emotions, it actually plays a fundamental role in filtering socially significant stimuli, such as facial expressions and threatening signals. The hippocampus, on the other hand, helps direct attention based on past experiences and memory traces.

A study published in the journal Proceedings of the National Academy of Sciences (PNAS) explored in detail how these two systems work together when we observe social scenes.
 

Status-dependent eye movements

In the experiment, macaque monkeys watched 15-second videos featuring two unfamiliar individuals: one displaying threatening, dominant behavior, while the other displayed conciliatory, submissive signals. While the animals watched the recordings, the researchers recorded their eye movements using an infrared eye-tracking system and simultaneously measured the electrical activity of the amygdala and hippocampus. They examined what are known as local field potentials (LFPs), which reflect the coordinated activity of larger groups of nerve cells. Within the first few seconds, it became clear that the observing monkeys looked longer and more frequently at the dominant individual. This clearly indicated that they recognized the social hierarchy.

One of the most important findings of the study was that amygdala activity changed even before eye movements began, when the monkeys were preparing to look at a higher-ranking individual. In other words, when the gaze shifted from a subordinate individual to a dominant one, characteristic activity in the 20–25 Hz range appeared in advance. Conversely, when the gaze shifted from the dominant to the subordinate individual, the neural response only appeared after the eye movement.

This suggests that

the amygdala does not merely process visual stimuli, but also "tags" socially important individuals in advance and prepares the visual system to observe them.

In other words, the brain determines who is important before our eyes focus on the person.

The interaction between the dominant (right) and submissive (left) monkeys shown in the video

Dominance and “thinking with someone else’s head”

The researchers also analysed the gaze paths of the observing monkeys in detail and distinguished between gaze-following and shared attention saccades. These eye movements provide important insights into how we understand the intentions and mental states of others.

When the monkeys performed gaze-following movements—that is, when they looked where the dominant individual in the video was looking—high-frequency oscillations in the amygdala and hippocampus increased. This is a sign of intense information processing and attention:

the focus of attention of those higher up in the hierarchy is "contagious," meaning that the brain mobilises extra energy to see what the leader is looking at.

In other cases, a shared attention situation developed when observers directed their gaze to the same point—for example, the face or eyes of another monkey—as their conspecific in one of the videos. These saccades were more frequent on the part of the subordinate individual, suggesting that the viewers of the recordings actively tried to interpret the tensions and intentions between the actors, reacting particularly sensitively to conciliatory, appeasing gestures.

The hippocampus showed particularly strong post-saccadic gamma activity in these situations, meaning that it is mainly activated when the observer draws conclusions about the intentions or focus of attention of others.
 

What does all this mean for humans?

Although the study was not conducted on humans, the brain systems involved in social understanding are very similar. The research provides a precise picture of how social status is integrated into our basic perceptual processes: the amygdala not only processes visual details, but also integrates abstract information such as social status into eye movement planning.

It is no coincidence, that at a meeting we look at the leader first

– this is the result of a deeply rooted neurological process.