1. In both active and passive groups, the correlation between spatial ability and performance was attenuated, relative to previous studies In contrast to the previous studies, the difference between high and low spatial participants was not significant in either condition. Once again, active and passive participants did not differ significantly, even though active learners used a more intuitive interface than in the previous study. As in Experiment 1, interactivity moderated the correlation between spatial ability and performance. The performances of high and low spatial participants differed overall, but when analyzed by condition, the difference was significant only in the passive condition In Experiment 2, active and passive participants did not differ significantly. That is, when the visual information was identical, interactivity did not confer an advantage. Above: Vandenberg Mental Rotation Test Right: Guay Visualization of Views Test Performance was correlated with 2 spatial ability tests: Passive Condition r=.25 n/s Active Condition r=.29 n/s Active Condition r=.30 n/s Passive Condition r=.54 p<.01 Experiment 2 found that, when the visual information was identical, there was no difference between participants who had active control and participants who did not. However, this finding may have arisen from the non-intuitive nature of the key-press interface. To assess this, we replicated the study, using a more intuitive, hands-on interface. How Learners Comprehend and Interact with 3D Computerized Representations of Anatomy-Like Structures Peter Khooshabeh 1, Madeleine Keehner 1, Cheryl Cohen 1, Mary Hegarty 1, & Daniel R Montello 2 University of California, Santa Barbara 1 Department of Psychology 2 Department of Geography General Method In three experiments, we investigated the roles of spatial visualization ability and interactivity in the comprehension of 3D computer visualizations. The stimulus represented a fictitious, “anatomy-like” structure. We used a cross-section drawing task to explore the nature of learners’ mental representations. Our research questions were: 1.How well can people mentally represent cross-sections? 2.Is spatial ability correlated with this skill? 3.Does interacting with the visualization significantly improve performance? 4.How do individual differences in spatial ability relate to differences in the use of interactive capabilities? In all experiments, we compared the performance of active participants (who were allowed to interact with the visualization) and passive participants (who were not allowed to interact with it). We used different experimental designs to establish whether it was interactivity per se, or the visual information available, that affected performance. Research Questions The ability to visualize cross- sections is important in comprehending the relationship between real 3D anatomical structure and 2D MRI, ultrasound or X-ray images. What factors contribute to this skill? Individual differences in spatial ability predict performance on this task. However, Interactivity moderates this relationship. Under some conditions, interactivity helps performance, but when the visual information is identical it makes no difference. Conclusions Scoring The drawings were scored on 4 standardized criteria: 1.Number of ducts: Does the cross-section contain the correct number of ducts? 2.Outside shape: Is the outer shape correct? 3.Duct relations: Are the spatial relations among ducts correct to +/- 20 degrees? 4.Duct position: Are the ducts placed in the correct region of the slice? Results Undergraduates were asked to draw cross sections of an anatomy-like structure. Printed diagrams of the structure were superimposed with a vertical or horizontal line, and the task was to draw the cross-section that would result if the object was sliced at the line. During the task, participants either actively manipulated or passively watched a dynamic rotating 3D computer visualization of the structure. Spatial ability is correlated with the ability to represent cross sections of computerized 3D structures Interactivity benefits performance, but only when interacting with the visualization produces different (and presumably “more helpful”) visual information about the structure If the visual information is held constant, interactivity does not benefit spatial understanding. This suggests that the quality of information available to a learner is at least as important as interactivity per se Although it does not necessarily improve overall performance, interactivity does attenuate the correlation between spatial ability and performance An analysis of the patterns of interactivity revealed that participants used the naturalistic interface more Passive participants in Experiment 3 benefited more than those in Experiment 2 Patterns of Interactivity Experiment 2 Sample cross- sections drawn by participants Results In a previous experiment (Experiment 1) showed that interactivity improved performance, relative to a continuously looping rotation. However, the visual information available to the two groups differed. Experiment 2 examined whether this finding held true if the visual information was identical. We used a yoked design, so that the interactive manipulations made by one (active) participant (using a key- press interface) were recorded and later played back to another (passive) participant. This ensured that active and passive participants had access to identical visual input. Active group (N=30) Allowed to manipulate the visualization via key-presses to select x, y and z rotations. Manipulations were recorded. Passive group (N=30) Not allowed to interact with the visualization. Saw the previously recorded manipulations made by active participants. Experiment 3 In Experiment 3, we replicated the paradigm using a more intuitive hands-on control system (an Inertiacube 3-dof motion tracker mounted inside an egg-shaped casing). As participants held and manipulated the egg, their movements were translated directly to the on-screen structure in real time, providing total freedom of movement and more a naturalistic sense of control. Active group (N=30) Allowed to manipulate the visualization via the hands- on interface. Manipulations were recorded. Passive group (N=30) Not allowed to interact with the visualization. Saw the recorded manipulations of active participants. Results *Significant at p<.01 Data were analyzed so as to determine how participants interacted with the stimulus. The parameters that were used were time spent on angle and angle change with respect to time. Start position Test Page view Most informative view Experiment 2 Experiment 3