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How can we encourage colleagues and other stakeholders to tackle issues such as climate change, inequality and racial discrimination? Psychologists have known for decades that information alone is insufficient to change attitudes – let alone motivate people into action.

Emphasising the size of a problem – if a vast number of people are adversely affected – is one way people try to raise an issue’s profile. However, a recent study by US-based behavioural scientists Yanna Krupnikov of Stony Brook University and Adam Seth Levine of Cornell University suggests that this approach may be flawed.

Effective tools

Broadly speaking, two main types of evidence can be used to support a proposal: a case study or statistical information. A case study may focus on the story of a real customer, stakeholder or small group of individuals; statistical evidence uses numerical data such as the probability of a problem occurring or the numbers of people troubled by the issue.

Krupnikov and Levine found that individual case studies are generally effective tools for engaging audiences. However, statistical data is only occasionally effective. Raw numbers (eg ‘12.8 million of 19 to 29-year-olds are affected by this issue’) tend not to be persuasive.

Using a story about the experience of an individual or particular group of people continues to be one of the best tools for engaging audiences

Percentages are effective only when they reinforce the fact that a significant majority of stakeholders are involved. For instance, saying ‘76% of adults are affected by this problem’ is roughly as persuasive as using a case study. When a percentage is low (eg ‘35% of customers are affected’), it is far less effective.

In other words, percentages are persuasive only when they demonstrate that a considerable majority of people are impacted by an issue. By contrast, using a story about the experience of an individual or particular group of people continues to be one of the best tools for engaging audiences.

Some people believe that rationality should rule in the workplace and that everyone should rely only on numerical data. However, the reality is that most people cannot help but be swayed more by stories than statistics.

Repetition’s power

A separate study led by Stefan Schulz-Hardt at the University of Göttingen in Germany confirms another way in which audiences are not completely rational. From a logical point of view, hearing the same argument multiple times should be no more persuasive than hearing it merely once. Repetition constitutes redundancy.

However, the researchers found that audiences in face-to-face discussions and when reading written arguments are measurably swayed to behave differently when an identical statement is repeated. This suggests it would be a mistake to propose an idea or make an argument only once and assume it has been taken on board.

Impactful messages

Leaders often try to give inspirational speeches, mentioning the vision of the organisation, its purpose or how it contributes to a greater good. However, US-based academics Adam Grant and David Hofmann have found that there is another way to make such messages more impactful.

Organisations often ask their beneficiaries – people the organisation helped – to speak about the organisation’s products and services. Customers talk about the level of service they received; medical patients speak about how their lives were saved or improved by the end product of device manufacturers.

Speeches delivered by beneficiaries were more effective at boosting audiences’ subsequent task performance

In several experiments, Grant and Hofmann asked audiences to listen to inspirational speeches given by leaders or beneficiaries. In general, speeches delivered by beneficiaries were more effective at boosting audiences’ subsequent task performance.

Employees may naturally suspect that inspirational messages given by leaders are aimed mainly at getting them to work harder. They may be less sceptical of – and so more engaged by – beneficiaries speaking about their genuine, heartfelt experiences of the organisation.

Changing attitudes

Another rhetorical device for persuading audiences may be to find a speaker who has converted from an opposing point of view – someone who did not believe in climate change or anti-discrimination policies but now does. Research led by Benjamin Lyons at the University of Exeter in the UK found that having a speaker explain the process that prompted their conversion is more effective at changing attitudes than their explaining both sides of the argument.

When I run workshops on changing minds and making change happen, I make it clear that finding good case studies, repeating messages and identifying the right speakers to advocate a cause is more time-consuming. However, the studies outlined here confirm that such methods are also likely more impactful.

Dr Rob Yeung is an organisational psychologist at leadership consulting firm Talentspace.