By John Drury

A recent article on the Brexit debate suggested that there is a fear among Governments that Brexit would lead to ‘referendum contagion’. The term ‘contagion’ here denotes not only the idea of behaviour spreading rapidly, but also that this spread is uncontainable and undesirable in some way. It is a term that seems to be ubiquitous today. But it appears perhaps most regularly in three particular contexts: explanations for the spread of emotion; accounts of stock market ‘panics’; and explanations for the spread of violence.

On the one hand, the concept of ‘contagion’ seems to do a good job in describing the fact that behaviours spread from person to person. It seems to be the only way to conceptualize the phenomena when we seek to explain how, as in 2011, riots began in London but then seemingly similar rioting then subsequently occurred in Birmingham, Manchester, and Liverpool, apparently as a direct consequence of these first riots. The core idea of ‘contagion’ is that, particularly in crowds, mere exposure to the behaviour of others leads observers to behave in the same way. As well as being a popular cliché among journalists, ‘contagion’ is found to be a vital tool in academic accounts. In a recent Google Scholar search, we found 500 hits for 2015 alone, and very few of them referring to spreading disease. In research, ‘contagion’ is now used to explain everything from ‘basic’ responses such as smiling and yawning (where the mere act of witnessing someone yawn or smile can invoke the same response in another) to these complex phenomena we have mentioned, like the behaviour of financial markets and rioting. What is more, laboratory experiments on the ‘contagion’ of simple responses (such as yawning) serve to underpin the plausibility of ‘contagion’ accounts as applied to complex phenomena (such as rioting).

Despite this widespread acceptance, the ‘contagion’ account has major problems in explaining the spread of behaviours. In particular, there are boundaries to such spread. If men smile at a sexist joke, will feminists also smile in response to the men’s smiles? If people riot in one town, why is it that they also riot in some towns but not others? For example, in 2011, disturbances spread from London to Birmingham, Manchester, Liverpool and Nottingham but they did not spread to Sheffield, Glasgow and parts of Leeds.

Figure 1: Riots originally broke out in London.

Figure 2: Riots spread to other parts of the country.

The concept of ‘contagion’ cannot answer such questions. ‘Mere touch’ (literal or metaphorical) may be necessary, but it is not sufficient for influence. The notion of ‘contagion’ assumes that transmission is automatic. It does not take account of the social relations between the transmitter and receiver. The best it can do is simply re-describe, in a limited way, the fact of involuntary influence, rather than explain it. At worst, it pathologizes influence in crowds and elsewhere, by likening it to the action of a disease.

This month, we (Steve Reicher,Clifford Stott and I, along with research fellows Fergus Neville and Roger Ball) started work on an ESRC-funded project to test a new account of behavioural transmission, based on the social identity approach in social psychology. This approach suggests that influence processes are limited by group boundaries and group content: we are more influenced by ingroup members than by outgroup members, and we are more influenced by that which is consonant with rather than contradictory to group norms. The social identity approach is therefore ideally suited to explaining the social limits to influence, both for ‘basic’ phenomena and rioting.

Because the concept of ‘contagion’ has been employed across a range of settings, we will be using different research designs to address it and test an alternative. These include a series of experimental studies to examine generic processes, but also make use of a large body of secondary data to look at the specific case of the 2011 riots, where ‘contagion’ was one of the explanations mobilised to ‘explain’ the spread of behaviours.  We will use our findings to generate a wider debate about the nature of psychological transmission and the practicalities of addressing them.

This research is funded by the ESRC, Ref ES/N01068X/1