When “I” Becomes “We”, Even “Illness” Turns to “Wellness”: Why Group Life Is Important for Our Health

Vegetables, exercise, and friends are good for you. Whereas, you already know about the beneficial health effects of the first and second, we want to show you the importance of the latter. Have you ever spent time with friends and felt powerful, safe and indestructible in your group? That is because you share a social identity with them and this social identity influences your mental and physical health. Besides your friends, you have other group memberships—for example, your family or your classmates. These groups make you feel socially integrated and they are a great source of social support in stressful situations. In this article, we introduce the Social Identity Approach—a popular psychological theory, which explains how your feeling of belonging develops and why it is important to identify with a group of other people. Furthermore, we show how social identity can be manipulated and changed in the long term.

Christy wants to improve her health. She already knows that smoking is bad for her and that doing regular exercise is good. But, like most people (and even many doctors), Christy does not know that social relationships are just as important. For example, people who feel alone are more likely to develop mental or physical illness [ ]. Research

MENTAL AND PHYSICAL ILLNESS
Mental illness can a ect your emotions, thinking, or behavior. Physical illness, like pain in your body or a flu, can sometimes lead to mental illness. has shown that being a member of multiple social groups is good for your health. You have social groups at home (your family), in school (your classmates), and in the community (your neighbors). Your social groups define your identity and are a source of social support. Social

SOCIAL SUPPORT
Giving and receiving help from people in your social groups. support involves helping people out when they need it.

WHAT IS A SOCIAL IDENTITY?
Every person has a personal identity and a social identity. Your

PERSONAL IDENTITY
What distinguishes you from your friends. This might be your taste in music, your hair color, or the school you are going to.

SOCIAL IDENTITY
What you have in common with your friends. Think about the similarities between you and your social groups. Why are you spending time together?
personal identity is what defines you as unique. It distinguishes you from other children. The basis of your social identity are your social groups. For example, Christy loves to play football and often plays with other children. These children are as excited about football as Christy, and they form a group together. In psychology, we would say that Christy shares a social identity with the other children in her football group. Her football group becomes part of her own social identity. Surprisingly, you do not even have to talk to other people to share a social identity with them. Christy is walking down the street when she suddenly notices another person wearing a shirt of her favorite football team. Christy will feel more connected to that person than to someone who is wearing the shirt of a di erent team. Researchers have used similar situations in experiments to change the social identity of their participants. For example, they ask participants to wear same-colored t-shirts (resembling school uniforms or jerseys in sports), and ask them to think of similarities between themselves and the other participants. This allows researchers to see how people act when they share (or do not share) a social identity with each other. These kind of studies help us to understand how social identity a ects our behavior.

THEORIES THAT EXPLAIN SOCIAL IDENTITY
Scientists use theories to explain the things that they observe.

THEORY
A theory explains a broad range of phenomena using only a few assumptions. These general assumptions help us to understand how a specific phenomenon works.
Theories are useful because, even though there might occasionally be exceptions to them, they help us to understand complicated phenomena, like people's behavior. In the scientific study of social identity, there are two important theories: social identity theory and

SOCIAL IDENTITY THEORY
Your social group memberships shape your social identity and define you as a person.

SELF-CATEGORIZATION THEORY
Which of your social identities is active depends on the situation you are in. That is the reason, why you behave di erently in di erent situations. social identities define you as a person. Self-categorization theory says that which of your social identities is active depends on the situation. At a football match, Christy defines herself as a member of her team. At school, she defines herself as a member of her class or school.
In these social situations, Christie's personal identity is less important than her social identity for defining who she is as a person, and her social identities will have a stronger influence on her actions. In class, Christy will behave more quietly than she will on the football field. Self-categorization theory helps us to understand why people behave quite di erently in di erent places.

SOCIAL SUPPORT IS GOOD, BUT SOCIAL IDENTITY IS EVEN BETTER
People receive many benefits from their social groups. Social support is only one of them. Christy experienced this herself: she noticed that she can deal with problems more easily when she receives help from her friends. This is beneficial for her health, because she experiences less stress. Benefits from group memberships are mutual. Within Christie's football group, the children can both give and receive help. For example, if Christie knows how to perform a ball trick she might explain it to the other group members. As a result, all group members feel that they can achieve much more than they could alone. In psychology, we have found that people who experience such advantages from their social groups are healthier and experience less stress [ ].
However, it is not the support of just anyone that can have a positive e ect on your health. The health benefits of social support depend on your social identity [ ]. This is something researchers have confirmed in experiments. In these, participants were asked to perform a speech in front of two strangers (who were actually members of the research team). The participants had only limited time to prepare-very stressful! Half of the participants were told that the two strangers were part of their own social group, meaning the participants thought the strangers shared their social identity. The other half of the participants were told that the strangers were part of a di erent social group, so participants did not feel a sense of shared social identity with those strangers.
The strangers in both conditions-those with whom the participants believed they shared a social identity and those with whom they did not, either acted in a supportive way or in an unsupportive way. To act supportively, the strangers smiled and nodded now and then during the speech. This gave the participants the feeling that they were doing well. To act unsupportively, the strangers frowned and shook their heads, which made the participants feel insecure.
Before, during and after the speeches, the researchers took saliva samples from the participants and measured the amount of a stress hormone called cortisol in these samples. This allowed the researchers to assess the amount of stress that the participants felt. In the first condition, when the participants and the strangers shared a social  Figure   Experiment to test, when the interplay of social identity and social support reduces stress. (A) In Condition , in which the participant and the two strangers shared social identity, the social support of the strangers reduced the stress of the speaker. (C) When the two strangers acted unsupportively, the stress response was higher. (D) In Condition , in which the participant and the two strangers did not share social identity, the social support of the two strangers did not reduce the stress level of the participant. (B,D) It did not make a di erence if the two strangers who did not share social identity acted supportively or not. This tells us that social support is only e cient in reducing stress if you are supported by people, with whom you share a social identity. identity, the participants were less stressed. As a result, there was a reduced amount of cortisol in their saliva samples. In the second condition, when participants did not share their social identity with the two strangers, the cortisol in their saliva was higher than in the first condition. This showed the researchers that sharing a social identity with the strangers could help to reduce the stress of the participants. But they found another surprising result: in the second condition, the cortisol levels of the speakers in response to supportive and unsupportive did not di er-the way the strangers acted in response to the participant's speech did not matter (Figure ). What do these results tell us? They tell us that social support is only beneficial for your health when you receive it from people in your own social groups-people with whom you share a social identity [ ].

HOW CAN SOMEONE DEVELOP A SHARED SOCIAL IDENTITY?
There are several ways to influence your social identity. Researchers have developed a program called Groups Health, which helps people to feel more socially connected and While drawing her social identity map, Christy notices that she has two sport groups: her football group and her swimming group. She realizes that she always has to split herself between these two groups, which is stressful for her. For her birthday, Christy plans to take both groups to a movie. They all have a great time and the children start to form a movie group. Now, Christy no longer needs to split herself between the two groups and always has someone to go to the movies with. Christy now knows that being part of several social groups is not only fun, but also good for her health. Her goal is that her social groups reflect her identity. Therefore, she wants to build positive and lasting social relationships in her life. To avoid stress, it is important to her that her social groups are compatible with each other. Just like Christy, everybody should know about the importance of social groups. This way, every person can successfully use their social networks to their advantage. . Making support work: the interplay between social support and social identity. J. Exp. Soc. Psychol. :
. Groups Health: evidence that a social-identity intervention that builds and strengthens social group membership improves mental health. J. A ect. Disord.

CONFLICT OF INTEREST:
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
COPYRIGHT © Frenzel, Junker, Häusser, Haslam and van Dick. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

YOUNG REVIEWERS
ESCOLA PIA DE SARRIÀ-CALASSANÇ, AGES: -Hello folks! We are a group of students from Barcelona. We were all born in , and are in third of ESO, the third year of the Secondary school here in Spain. Because of our love for science and English, our teachers gave us the opportunity to take part in this amazing article review. This interest in English is due to the fact that some of us speak other languages like Dutch or French. Apart from this, many of us are keen on other things, such as padel, martial arts like judo, football, basketball, or even learning Chinese! AUTHORS SVENJA FRENZEL Svenja Frenzel obtained her master's degree in psychology at the Johannes Gutenberg-University (Mainz, Germany) in . For her Ph.D., she has been working in the Department of Social Psychology at Goethe University (Frankfurt, Germany). Currently, Svenja is working in several exciting social identity projects, in which she is investigating di erent aspects of social identity in teams. Therefore, she manipulates the shared identity of her participants. Svenja wants to get other people, and especially you, excited about scientific work. In her spare time, she likes to go skydiving and rock-climbing with friends, with whom she shares a social identity. *frenzel@psych.uni-frankfurt.de

NINA M. JUNKER
Nina Junker is an Applied Social Psychologist who studies teams, well-being, and the myth of work-life balance. At the moment, she is most interested in better understanding how groups can (in)e ectively work together and whether group members' views are similar to others' views, such as their supervisors'. She likes to bring a di erent angle to the study of established phenomena, challenging the kids.frontiersin.org March | Volume | Article | assumption of whether certain behavior or attitudes are always "good" or "bad." Like all of us, they may sometimes be good for some, but bad for others.

JAN A. HÄUSSER
Jan Häusser is a social psychologist who studies how stress and sleep deprivation a ect people working together, how stress can be reduced by means of mutual support and feelings of togetherness, and how (certain types of) work can make you sick. Moreover, he is interested in all types of weird topics, which is why he recently arranged cockroach races to test whether they run faster when other cockroaches are watching, and he set up a booth in front of the canteen, to test if hungry students are less likely to share-all in the name of science.