Visualizing macroevolutionary timescales : students’ comprehension of different temporal representations in an animation

Background: Macroevolutionary time is a difficult idea to grasp and is considered to be a threshold concept in teaching and learning evolution. One way of addressing this subject is to use animations that represent evolutionary time. The aim of this descriptive and exploratory study was to investigate how various representations of time in an animation affect the way undergraduate students comprehend different temporal aspects of hominin evolution. Two factors, namely differences in timelines (the number of timelines with different scales) and the mode of the default animated time rate (either constant throughout the animation or decreasing as the animation progressed) were combined to give four different time representations. The temporal aspects were investigated using undergraduate students’ ability to find events at specific times, to comprehend relative order, to comprehend concurrent events, to estimate the duration of time intervals and their ability to compare the lengths of time intervals. Results: The results revealed that “finding events at specific times” near to the end of the animation (closer to present time), where the sequence of events appeared very quickly, was more difficult for groups working with animations with only one timeline. We also found that the ability to comprehend concurrent events can be impaired if several timelines are displayed and the animation speed is relatively high. The ability to estimate the duration of a time interval was more difficult for groups working with animations with only one timeline, especially at the end of the animation where the sequence of events occurred quickly. Making correct comparisons of time intervals was relatively independent of which animation was used with one notable exception: groups working with an animation featuring several timelines and a decreasing default animated time rate performed worst at comparing events with intervals that spanned parts of the timeline with different scales. Conclusions: Our results indicate that the choice of animation should depend on the teaching intention. However, a visualization with several timelines, and an animated time which slowed down toward present time, generated the best results for the majority of items tested. Temporal scale shift may interfere with the perception of time in cases where durations are compared