Does length really matter? effects of number of pages in the informed consent on reading behavior: An Eye-Tracking Study

The use of an adequate informed consent (IC) is a current concern in psychological research. A good understanding of the IC is an important step to certify that the participant’s decision to participate in research is informed and free. However, the number of pages in the IC may be a main hinder factor in both reading and understanding the IC. The length of information in ICs has been a matter of debate for a long time, however, no clear guidance has been given. As the reading process requires visual attention, eye movements can provide an objective and quantitative measure of visual behavior that can also be viewed as a proxy of reading behavior. Thus, the objective of this study was to examine how the number of pages in the IC influences reading behavior. Sixty participants were randomly assigned in three experimental conditions (1 page vs. 2 pages vs. 3 pages) while eye movements and the reading time were recorded. Results have shown no differences in average reading time between different lengths. However, a larger number of fixations per word was found at the bottom of the page (area of signature) in the IC with one page in comparison to the bottom of the page in ICs with two or three pages. These findings demonstrate that eye movements are a rich source of information by providing details of relevant/irrelevant contents in the IC.