Influencing Behaviour

We make decisions every day. Some, like choosing what to eat for breakfast, seem trivial. Indeed we are often unaware that we are even making them. To others, like choosing a medical treatment, deciding whether to apply for a job, or electing a president, we afford much greater deliberation. We are normally aware of making those decisions, yet we may not be aware of the forces at play to influence our decision, both internal and external. In light of the recent US Presidential Election, I want to know if there are lessons in decision making for Public Health.

Persuasion is all around us when it comes to politics, and it comes as part of a framework. When we switch on the television, we are likely to see a member of the political establishment trying to convince us their way is best, with ubiquitous masquerading of normative ideas as facts. If we wait it out to see the subsequent analysis by political correspondents or open a newspaper or read an online article from an established news organization, our view is further shaped by those institutions, along with their own bias. The third part of the framework, the blogosphere, has come into play in a powerful way since the start of the millennium. These three entities are referred to by Daou as “The Triangle,” which are able, as a whole, to more successfully capture our attention and create a greater impact.

John Kerry’s 2004 presidential campaign demonstrated a huge disconnect between the Washington political establishment and “the netroots.”  Attempting to learn from this, both the Clinton and Obama campaigns for the Democratic primaries in 2008 tried to bridge the gap. While Clinton’s team attempted to make the language of her texts and emails to supporters cosy and familiar, Obama kept a more formal approach but allowed supporters to form their own sub-networks, exponentially increasing the power of the network.

At face value, the attributed winning strategy seems highly noteworthy. And yet, somehow I’m not convinced. Is it evidence based enough? Where among any of this is the hint that the relationships we are seeing are because of causation rather than just association ?

There is an answer in the world of online persuasion, which satisfies the part of me that is grounded in making evidence-based decisions. As Sasha Issenberg describes in her book “The Victory Lab,” online entities are able to collect data on what their users do, and this gives us an opportunity to really experiment. Dan Siroker employed an experimental approach as part of the 2008 Obama campaign, adjusting elements of the campaign website like the sign-up box or the displayed content. The different website appearances were shown randomly to different users, and as such they were able infer causation in a much greater way than comparing observations of events of the past. In public health and indeed all the biological sciences, we see experimental data as being superior to observational data when we can ethically and practically obtain it.

But what about the choice of content? We can broadly divide this into positive and negative. Political campaigns tend to devote the lion’s share to negative advertizing: in 2012, Barack Obama designated 85% of his $404 million TV advertising campaign on negative ads, while Mitt Romney spent 91% of his slightly larger $492 million [link] on negative ads.

This is not just because the campaigns prefer a mud-slinging match, but rather because of the way our brains are wired. As a whole, humans are much more susceptible to negative information. This is evident on a very basic level, with greater event-related brain potentials (essentially a measure of brain electrical activity) in response to negative images. Roy Baumeister and colleagues describe how this also affects our behaviour, from the way we provide and receive feedback at work, to the likelihood of our relationships to succeed. On the latter, the authors show that positive interactions must outweigh negative ones by a ratio of five to one if a relationship is to succeed. It is not a coincidence that the proportion of advertising budget spent on negative advertizing, as referenced above, mirrors this ratio.

This is called our negativity bias.

Icek Ajzen’s Theory of Planned Behaviour says that, while the most important determinant of our behaviour is our intention to perform the behaviour, impulses and habits can get in the way and prevent us from making the jump from plan to action. Political campaign managers are all too aware of this and it is this that sets two distinct processes in securing votes – the first is persuading the voter, the second is getting them to the voting booth, the so called “Get Out The Vote” effort.

Nobel prize-winner Daniel Kahneman writes in “Thinking, Fast and Slow” that this is due to our dual processing in achieving our planned behaviours: on the one hand we have our rational process which is slow, effortful and rule-governed, while on the other we have our intuition, comparatively quick, effortless, yet vulnerable to emotion. Behaviours formed from intuition are often less healthy, like choosing chocolate cake over fruit salad when we are stressed. A growing body of work in public health shows that we may be able to exploit intuitive thinking for better health, however.

External cues such as packaging and container size can powerfully impact the amount people eat. A 2001 experiment provided participants with free popcorn at the movies, either medium or large. The catch was that the popcorn was five days old and tasted like styrofoam packing. Despite this, on returning their buckets at the end of the movie, those who had the large bucket had consumed 55% more popcorn than those with the medium sized bucket. (The taste was actually so bad, that many participants asked for their money back, forgetting the popcorn was free).

Similar effects were seen in a randomized trial assessing the efficacy of a simple portion control plate for obese patients with Type 2 diabetes. While participants were free to eat what they chose, 16.9% with the plate lost more than 5% body weight, compared to only 4.9% of those who continued as normal.

As we realize these effects more and more, the subsequent challenge will be to effect policy change. There are many who regard such attempts to change health behaviours as paternalistic. I argue they are, rather, Nudges. Nobody is forced to do or give up a particular behaviour, yet we might bring about real change. After all, we face an onslaught of nudges from our surroundings – in the form of advertising, and indeed other forms of persuasion – all the time.


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