People view the Swift Boat Veterans for Truth attack ad against John Kerry as a turning point in the 2004 election, but the research says it probably didn’t have much of an effect. While billions of dollars are spent on political advertisements, they are generally ineffective. However, they do reveal a lot about both advertising and human nature.

To start, political advertising seems to be ineffective because many people have already made up their minds. As a result of confirmation bias, once a mind is set any new information will be viewed in relation to preserving previous thoughts. As George Washington political scientist John Sides told NPR, “When voters are confronted with inconvenient facts, it is oftentimes difficult to persuade them that those facts are, in fact, facts. When supporters of President Obama see negative information about Obama, they don’t think it is true. To the extent it is true, they find ways to explain it or rationalize it — they discount it.”

Since most of the viewers are already committed to a party or candidate, there are very few people out there whose minds can be changed. But, Rolling Stone’s basic position is that this small number of people is large enough to sway our elections and thus justifies the large ad spends. However, the data doesn’t fully support that conclusion. In fact, the person or campaign launching an attack ad often loses support, and the best research in negative ads’ favor suggests that they are most effective when shown sparsely.

But here’s where it gets more complicated and even more interesting. What if it’s not just confirmation bias? What if the ads are ineffective because we have entirely different ways of seeing the world? Fear based ads and imagery are more effective at pushing people to vote conservatively. In fact, reminders of disease or contamination, pictures of children, and images of the flag have all been shown to push people to vote more conservatively in the past. Could that lead us to believe that conservative people in general think more emotionally or make fear-based decisions?

Yes. In fact, the data shows that conservatives and liberals don’t just have minor disagreements, they have different brains with which to interpret the world. Conservatives are more affected by fear – they have a bigger amygdala, respond more sensitively to negative stimuli, interpret things as being more threatening, and are focused on preventing negative outcomes. Liberals, on the other hand, tend to be more open-minded, open to risk, capable of change, and focused on creating positive outcomes. Differences in thinking style may also shed light on how to approach these groups. Studies show conservative policies are in general derived from more “low-effort” thinking, while more deliberate (or possibly censored) thought leads to more liberal decisions. A simple summary of these studies can be found here.

Undoubtedly, that should begin to explain the political divide and why compromise seems to be so hard. But it also hints at how to bridge the gap. If you can flip your perspective to examine the issues from either a risk aversion or gain focus, policy issues begin to make more sense. For example, opposition to or support for the Iran Nuclear Deal, Immigration, Stimulus spending, etc, are more relatable when you can see how the other side approaches the issue.

In terms of advertising, the takeaways seem to be focus on thorough action plans and benefits while building a coalition of support with liberals and focus on the preservation of order or the avoidance of negative outcomes while reaching out to conservatives. Products which stereotypically fit a certain type of person may also benefit from these approaches.