Discussion

According to widely used theories regarding the use of PowerPoint in educational contexts, such as multimedia learning theory, the best way to improve the effectiveness of PowerPoint presentations is to use a combination of images and voice or images and texts (Roberts, 2018a). In our study significant differences emerged both in the factors for using PowerPoint, as measured by the UTAUT-2 scales, and in the type of slides predominant in the three macrodisciplines studied. As expected (H1), there was a high predominance of visual or combined presentations in the natural and medical sciences, while the social sciences were still dominated by textual slides, which could limit their effectiveness in learning. Indeed, as stated in H2, the use of textual slides was

associated with a purpose based on rote learning. These results (H1-H2) are consistent with the findings of previous research (Smith-Peavler et al., 2019; Hertz, van Woerkum and Kerkhof, 2015), which showed that the natural and medical science disciplines were more focused on images because of the nature of the disciplinary content. Conversely, Johnson and Christensen (2011) did not find any effect of the type of slides on

psychology students' performance. However, their design simply converted text-based slides into visually-rich slides. The pedagogical value of the content of each slide was not called into question. In fact, when looking at the examples they presented in their study, the slides are clearly intended to define key concepts so that just transferring a text-only slide to a visually-rich slide, although probably more attractive to students, did not necessarily increase the pedagogical value. In Roberts' studies (2018a; 2018b), specially designed images were used to foster critical reflection, which obtained positive results. Perhaps the incongruence between the type of slides and their reported purpose partly explains the ambiguous results of previous research about PowerPoint

effectiveness.

A second observation derived from our findings is that programs related to medical sciences have their own pattern of factors for using PowerPoint, while both natural sciences and social sciences share a more similar pattern. Although a specific pattern of factors for using PowerPoint was expected in the three groups (H3), only the medical sciences instructors had a more positive outlook regarding the expected benefits associated with the use of PowerPoint. They also showed greater dependence and automatism in this use. It is possible that this positive but dependent combination explains in part why this discipline gives less importance to critical reflection through PowerPoint. Perhaps the decision to use PowerPoint to stimulate critical reflection upon content requires a critical stance towards the technological tools used to present the content.

We also observed that high scores on the habit scale, defined as the level of

dependence upon the use of PowerPoint in the classroom, are strongly related to the use of PowerPoint to study for exams, while low scores on this scale are related to the use of PowerPoint for critical reflection. This pattern remains stable in the three areas of knowledge evaluated. This is particularly interesting because, as far as we have been able to discern, this relationship had not been studied in previous research.

3.5.1. Implications

We believe that our study has implications on a theoretical and practical level. At the theoretical level there are few studies that have directly compared the use of

PowerPoint in different areas of knowledge. This research aimed to gain further insight into the factors that influence its use and the different patterns of use of PowerPoint in the macrodisciplines of the medical, natural, and social sciences. Additionally, we added some factors for using PowerPoint, as measured by the UTAUT-2 dimensions, revealing the significant role habit is playing in all three disciplines. Finally, we

postulated that the incongruence between the type of slides and their reported

pedagogical value could explain some of the inconsistencies found in the effectiveness of PowerPoint in past research.

On a practical level, some differentiated profiles have been established in the use of PowerPoint, which can encourage the design of specific strategies by discipline. This is particularly worthwhile because this research emphasizes what type of slides are usually associated with a specific function, which opens the way to new interventions and investigations to understand the importance of the design of the slides being consistent with faculty members' pedagogical approach.

It is clear from this study that there are specific patterns of PowerPoint use,

depending on disciplinary content. This finding has important implications: if the social sciences, due to the epistemology of these disciplines, use more textual slides, which are associated with rote learning, it becomes important to foster a more thoughtful use of PowerPoint. For example, instructors might be encouraged to think about how it can best be designed to enhance learning.

Finally, a higher dependence on the use of PowerPoint for lectures, as evaluated with the habit scale in this study, is associated with using PowerPoint to study for exams. Of course, this means that PowerPoint goes from being a support tool for teaching, to simply helping students to pass their exams. This finding is fundamental and calls for developing strategies that help faculty members in the support of innovation and critical use of educational technologies such as PowerPoint, which is more than simply implementing policies to encourage its use. Instructors who use PowerPoint in a way that we have called "critical use," with low scores on the habit scale, often report that they use PowerPoint to encourage students to reflect critically

upon content. Developing strategies for this type of use should be a priority in all higher education institutions in order to exploit the pedagogical potential of PowerPoint.

3.5.2. Limitations and Future Research

As in any study, there are some limitations that must be mentioned. First, the sample is relatively small. Although it is not uncommon in such research to have a sample of similar size, we suggest replication of this study with a larger number of faculty

members before generalizing its results. Additionally, an expanded sample would allow observing the differences in PowerPoint usage patterns between different majors within a particular macrodiscipline (e.g., psychology and sociology in social sciences; biology and physics in natural sciences; medicine and nursing in medical sciences).

Second, we used only self-reports of the faculty members, so it is possible that the results are biased. The original design of this study included the use of actual slides as provided by respondents in order to obtain an objective measure. However, because of logistical problems we were unable to do so. Combining that kind of objective measure in a future study would allow evaluation of the existence of bias with respect to the type of slides used by comparing the perception of the faculty members with an objective analysis of the slides they actually used.

In this study, faculty members who claimed to use PowerPoint primarily to help students memorize key concepts also claimed to use mainly textual slides. This association between textual slides and rote learning is particularly interesting since criticism of the use of PowerPoint refers precisely to the fact that it has been dominated by a text-centric trend, whereas in this study only 24% of the instructors indicated that they preferred using textual slides. Is it possible that faculty members underestimate their use of textual slides, thereby favouring a more rote-based learning than they might think they are doing.