According to Wansink and Tal, the effects seems to be strongest in people who agreed with the statement "I believe in science". So, a graph makes a claim more "sciencier" and, therefore, more credible? Also, does this mean that science believers aren't being as critical because they already have an underlying belief in what they are reading?
I thinks this is a good way of conveying the power of graphs to students in a statistics class as well as the need for better scientific literacy/statistical consumerism/skepticism. I think it is also a good example of Elaboration Likelihood Model.