Group behaviour: one for the team

Researchers at Leiden study group behaviour. One of their findings is that when people make sacrifices for another member of their group, it is probably instinctive. Insights of this kind enable us to better understand and influence the social processes in a neighbourhood or company.

We derive some of our identity from the groups with which we feel a connection: our family, circle of friends, department or sports team, for example. Leiden psychologists study group behaviour. They want to find out how an individual relates to the group, and what happens in the interaction between groups. With this knowledge, we will be more able to understand and influence the social processes in a neighbourhood or company, for instance.

Evolutionary advantage

Living together has given people many advantages. Close-knit groups, in which people support and complement each other, exchange favours and perform complex tasks together, find it easier to survive than solo individuals. But group dynamics can also be counterproductive. People are excluded or bullied, group members fail to cooperate properly, or groups make life difficult for other groups. Leiden psychologists conduct experiments with behaviour, measure physiological responses and look inside the brain. They aim to obtain a fundamental understanding of the group processes that we see all around us: at school, in the village, in the mosque or at the office, with the ultimate goal of making such processes more controllable.

Group status affects heart rate

Psychologist Daan Scheepers conducts research on status differences between groups and group members’ responses to these differences. It is known that in a dominance contest the heart rate and blood pressure increase more in the members of the ‘inferior’ group than in the members of the dominant group. Scheepers discovered that it is not only the group status itself that is important here, but also how legitimate that status is. If rumours are spread during an experiment, suggesting that the low status was not legitimate – ‘people are cheating’, ‘ the referee is rubbish’ – then the members of the inferior group exhibit a better physiological response and they also perform better in the next round. The opposite effect can be seen in the members of the winning group. If their status was called into question, they felt less sure of themselves, which was reflected in their heart rate and blood pressure.

Altruism as instinct

Studies have shown that individuals are willing to sacrifice their self-interest if this benefits a member of their own group. Research is conducted in Leiden into the roots of this phenomenon. Is altruism a conscious, rational decision or an intuitive, almost instinctive response? Psychologist Carsten de Dreu has found indications for the latter. He discovered that experimental participants who make a decision favouring a member of their group do this faster than participants whose decision is in their own favour. And participants also make an altruistic decision faster if they are working on a cognitively demanding task, such as solving a maths problem, at the same time. This suggests that the altruistic decision to help a group member is an unconscious response. Giving priority to self-interest uses more cognitive capacity. De Dreu also discovered that when we make altruistic decisions the hormone oxytocin activates the parts of the brain where our emotions are regulated, and not the parts where rational consideration takes place. It seems that solidarity with fellow group members has become deeply rooted in our brain during the course of evolution.