6. Conclusion
In this study we found a positive effect of visibility of a lecturer on reported attention, at least when participants had been watching a weblecture for more than 15 min, which probably contributes to students' reported preference for lectures with video of the lecturer. After a short time of watching a weblecture, no differences on reported attention were found between the different visibility-modes. An explanation, to be studied in further research, is that a reduced attention span will lead to different strategies to remain attentive during the weblecture where visibility of the lecturer contributes to these strategies. At present, educational institutes should offer their students a choice on their preferred way of watching a weblecture: with or without a visible lecturer, at which size, and with large or small images of the slides.