Are you attending? Everyone else is

Logging onto my Facebook account the other day, I saw the above question posted in one of my university society groups. The person who asked the question (probably unknowingly) employed an effective persuasive technique in order to get people to click ‘Yes, I will be attending’.

The technique is called social consensus and the basic principle is that the more it looks like other people are doing something, the more likely another person will be to join in. It promotes conformity through informational (‘If other people are going, that must be the right thing to do’) and normative (social pressure to join the majority) social influence.

Reingen (1982) demonstrated the effectiveness of social consensus in a paper involving a number of experiments, three of which are relevant to the influence example mentioned above.

In the first experiment in the paper, undergraduate students were asked to donate money to the Heart Association in one of two ways. The first way was to simply ask them to donate (request only control condition). The second way involved showing them a list of 8 other students (from the same university) who had donated, and then asking them to donate afterwards (list condition). It was found that when just asked to donate, 25% of participants did so however, when shown the list first, 43% of participants donated to the Heart Association. This result shows that we are more likely to comply with a request when we can see that others have also complied with that request.

The second experiment involved adult residents of randomly selected homes in South Carolina. Participants were asked the same request regarding donating to the Hear Association. Similarly to experiment 1, it was found that those who were only asked to donate complied 47% of the time, whereas those who were shown a list of others (also residents in the area) who had donated gave money 73% of the time (significantly more often).

Experiment 3 involved asking undergraduate students whether they would be willing to donate blood. Again, half of participants were just asked and the other half were also shown a list of 8 students form the same university who had already given blood. The results were similar to those outlined for the previous two experiments: only 3% of those who were simply asked agreed to donate blood; 33% of those shown the list agreed to donate. One weakness of this experiment (when compared to the others) is that the dependent variable was only behavioural intention (signing up to say they would donate blood); in the other two experiments a donation was actually made (a behaviour). This difference may explain the lower compliance rates for this experiment.

Table 1: The table above shows a summary of results from the paper. It can be seen that compliance was significantly higher in the list than the control condition across all 3 experiments.

So Reingen’s (1982) research shows that people are more likely to comply with a request if they can see that other people have already complied; they are conforming to other people’s actions (the actions of the majority). Similarly, in the Facebook question shown at the start of the blog post, people are more likely to respond ‘Yes’ because they can see that everyone else has previously responded ‘Yes’.

Social consensus has obviously worked well in the case I showed you above – everyone has clicked ‘Yes’, adding to the size of the majority and thus perpetuating the effect. The more the technique works and the more people who click ‘Yes’, the less likely future respondents will be to click ‘No’. I wonder how many people will turn up on Monday…

Reingen, P. H. (1982). Test of a list procedure for inducing compliance with a request to donate money. Journal of Applied Psychology, 67(1), 110.