OPINION8 January 2020

In praise of social identity theory

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Behavioural science Opinion

Crawford Hollingworth explores how social identity theory can be used to influence people’s behaviour, from increasing voter turnout to encouraging more physical activity.


Human beings are social creatures; our attitudes and actions tend to be heavily influenced by those of others, and in almost all societies there are unwritten rules about what behaviours are acceptable (or not) within specific group settings. Consequently, the power of social norms in behavioural change and social influence is widely recognised and is a popular tool among practitioners.

Recognising that behavioural change is an inherently social process, research from social psychology indicates that, for lasting change to occur, people need to internalise norms and use them as guides for their own behaviour. Most behavioural interventions to date have successfully used social norm awareness to nudge people towards a desired behaviour, for example, ‘92% of your neighbours reduced their water consumption over the past year’. However, for a more sustainable behavioural change, particularly for regular/habitual activities, the research suggests it may be more effective to go beyond norm awareness to norm internalisation. 

To explore this idea further, I’d like to introduce social identity theory; an extremely powerful concept well established in psychology but typically under-used in the behavioural change sphere.

Social identity theory recognises that human psychology and behaviour are heavily shaped by the group memberships that individuals internalise as part of their sense of self. For example, when an individual feels that membership to a specific group is particularly integral to their self-identity or self-concept, they will try to align their actions with those of the group – otherwise they’ll tend to experience some cognitive dissonance. Imagine you enjoy running and so you join a running group and start to identify as ‘a runner’. Perhaps all the other members of the running group are vegetarian, and you start to associate running with vegetarianism. Since you self-identify as a runner, and runners are vegetarian, it is likely that you will also start to eat less meat.

Joining the in-group

The social identity approach aims to influence behaviour by making it a defining and salient ‘in-group’ characteristic, such that new norms become accepted and integrated into our social identities. The integration and internalisation of social norms can help promote more sustainable behavioural change, something that interventions based on simple awareness of social norms may be less capable of achieving in the long run.

If people grow indifferent to what their neighbours do, for example, and become accustomed to the social norm statistic, these approaches will require ongoing and/or varying ‘nudges’ to achieve the desired behaviour. Once a behaviour has been internalised as part of our identities, we are more personally committed to it, and there is a higher chance that the behaviour will last (without repeated interventions)… And here lies the additional, unique benefit of using a social identity approach.

The social identity approach to behaviour change is beginning to be used more regularly – from promoting environmentally-friendly behaviours, to reducing the rising fear of immigration, to tackling our stubborn obesity crisis – and it is exciting to contemplate the power that this behavioural tool could have in promoting more long-term social influence.

Two ongoing, highly successful campaigns have recognised the importance of group identities in achieving behavioural change.

Getting people to get out and vote can be a notoriously difficult behavioural challenge. In the 2017 UK general election, voter turnout was 68.8%. In the US, approximately 60% of the eligible population vote during presidential elections, and only 40% vote during midterm elections. If every eligible voter could be convinced to vote, there could be a fundamental difference in election outcomes and how accurately the government represents public opinion.

Turbovote is an organisation based in America with the goal of increasing voter turnout. It understands that connecting the idea of voting with the group identities that people hold (for example, being an employee of a company, or a resident in a specific area, or a student) and clearly linking the outcomes of elections to their daily lives, is a highly effective way of getting people to vote. By connecting voting to specific group identities, Turbovote seeks to promote the integration of voting into individuals’ group identities such that they not only vote in the current election cycle but also identify as a voter for future elections. By the end of 2018, Turbovote had helped more than 2.7m people register to vote.

A second example is interventions that incorporate the idea of social identity to drive initiatives that build and encourage greater physical activity, for a healthier lifestyle. A growing body of research has found that individuals who identify strongly with a group in which exercise is the norm, report greater intentions to engage in regular exercise than those who identify weakly with such a group.

In many ways, the successful UK, and later Australian, campaign ‘This Girl Can’ drew on the social identity of women to tackle barriers to participating in sports. One of the major barriers identified in research was the fear of judgement. By focusing on making clear that this worry is common and showing how women just like them (all shapes, sizes, abilities and femininity) are taking part in sport anyway, it helped women overcome some of these mental barriers. According to Sport England, just one year after the campaign launch, 2.8m women reported being inspired to do more physical activity.

Many of society’s most pressing behavioural problems (such as climate change) require long-lasting changes to our behaviour; just imagine what could be achieved through harnessing this powerful social identity concept and realising the importance of norm internalisation. And, after reading this article, maybe ask yourself a probing social identity question – ‘do you identify with people in our industry driving new thinking and understanding?’

This article was first published in the October issue of Impact