Neuroscience

In the research article by McCabe and Castel their hypothesis asserts that brain imaging specifically fMRI and PET, which are usually displayed pictorially with highlighted brain areas of activation, have a significant effect on the readers’ conclusions concerning an articles credibility and are thus rated higher in scientific reasoning. They believe this is because it provides a physical basis for abstract cognitive processes. To substantiate these claims, they conduct three experiments to determine if a brain image has a significant effect on perceived credibility and what exactly about the image is persuasive.

In the first experiment, one hundred and fifty-six Colorado State University undergraduate participants were measured within-groups. Each participant read three articles, one as a control with no image, a second with a bar graph and a third article with a brain image. The experimenters attempted to control for possible confounds by giving short articles, all of which containing illogical reasoning. This may have prevented a ceiling effect if all articles were all scientifically sound. This also allows the experimenter to see the full effect of the independent variable with less possible confounds, especially when using a within-groups design. There was a significant effect between the brain image article and the bar graph, and the control with no image, in that the articles containing a brain image were significantly rated as higher scientific credibility than the other two kinds of articles presented. In the second experiment, the articles, sample size and sample population all stayed generally the same. One article with a topographical map of brain activation and one with an fMRI brain image. This allows experimenter to determine if it the complexity of a brain image compared to the bar graph is a causal factor in the significant results found in the first experiment. There was a significant effect, in that the fMRI imaged article was still perceived as significantly greater scientific reasoning than the article with the topographical imaged article. This leads experimenters to conclude that it isn’t the visual complexity of brain images that influence this reaction in readers.

Experiment three included roughly the same participants and sample population but also included students from the University of California. This experiment was a between-subject’s analysis with two by two subjects. One being with an image and one being with a brain image. Some of each of those articles included a critical comment at the bottom of the article. These articles did not include unscientific reasoning and were articles used by BBC. There was no perceived difference of agreement or disagreement based on the critical comment but did have a significant effect on the perceived appropriateness of that articles title. There was however, a significant difference between articles including a brain image compared to without regardless of comment, in that even when using equally logical publicized articles, brain images still receive a higher perceived credibility and logical conclusion than articles including no image.

As mentioned in the article, there was a small to moderate effect size in these experiments. The first suggestion to reinforce these findings (or discredit them) would be to increase the sample sizes in each experiment. Second it would be beneficial to repeat these experiments so that they are measured as between-groups design. This would control for more possible confounds when rating the logical reasoning of the article by participants. I would also like to know exactly which experiment had exactly which effect size. It also would have been advantageous to include all statistical findings of all three experiments rather than only thoroughly representing the results of experiment one. Especially considering the assumption made that these findings apply to lay-readers, thus appropriating that the readers of this article are not and are concerned about the microrotation of neuroscience data. Another way to strengthen or specify these findings would be to design a reaction for these articles allowing the reader to elaborate on their response. This may narrow the focus of future research as well as highlight any additional confounds the experimenter is not aware of.