Graphs persuade some more than others

Sometimes the easiest way to persuade people is the simplest. Just including a graph as a peripheral cue convinced almost all (96 per cent) subjects of a recent study compared to just 67 per cent of the control group, who read the same information in text form (Tal, et al., 2016).

The research appears to show that graphs increase the credibility of the source and the perceived accuracy of the information they are communicating. Previous research has shown that the more credible the information is, the more persuasive it is because it motivates message recipients (or at least some message recipients) to process the message and judge it on its argument strength (DeBono & Harnish, 1988; Wu & Shaffer, 1987).

Figure 2 = A little bit of humour from the study.

The study also showed that it wasn’t simply the repetition of the information in both text and in graphic form that led to the persuasive effect, it was merely the inclusion of the graph itself, supporting the hypothesis that its inclusion led to a peripheral route attitude change. The authors confirmed this finding by removing the graph and including a scientific formula, which produced similar results.

Interestingly the authors performed a separate study in association with this to determine whether a message recipient's support for science had a protective effect against this form of persuasion, and indeed it did.

Therefore it seems as if it is the perceived scientific nature that including the graph adds to information that persuades people with lower levels of support for science.

Discussion

The authors hypothesize that those that respond to the visual cue, process the information like this:

  1. The information contains a graph (premise);
  2. Graphs signal a scientific basis (premise);
  3. Therefore, the information has a scientific basis (conclusion);
  4. A scientific basis indicates truth (premise);
  5. Therefore, the information is true (conclusion).

This is obviously a peripheral route processing mechanism that is open for manipulation and exploitation. Interestingly it points to the success of pseudoscience, which to the untrained eye can look like science and uses the same visual cues and language as science, but without the attention to facts. However it is an important reminder to science communicators that they should not try to simplify their all of their information to a year 10 standard of education, because giving cues – even those that some people won’t understand – can be highly persuasive. And their pseudoscientific competitors are doing it too.

The fact that elements associated with science can so easily enhance persuasion urges caution in the communication of purportedly scientific claims, and a more critical eye when it comes to assessing claims that are given a scientific veneer.

References

  • DeBono, K. G. & Harnish, R. J., 1988. Source Expertise, Source Attractiveness, and the Processing of Persuasive Information: A Functional Approach. Journal of Personality and Social Psychology, 55(4), pp. 541-546.

  • Tal, A., Wansink & Brian, 2016. Blinded with science: Trivial graphs and formulas increase ad persuasiveness and belief in product efficacy. Public Understanding of Science, 25(1), p. 117–125.

  • Wu, C. & Shaffer, D. R., 1987. Susceptibility to Persuasive Appeals as a Function of Source Credibility and Prior Experience With the Attitude Object. Journal of Personality and Social Psychology, 52(4), pp. 677-688.