Discussion
Through this study, it was found that (1) participants with low SA had significantly lower heart drawing scores than those with high SA despite no significant differences in reported ICL, (2) males had significantly higher SA than females, (3) there were no significant differences in reported ECL when signalling in the form of colour-coding was added to the PR3DM, and (4) participants who studied the liver A3DM had significantly higher post-test scores than those who studied the liver PR3DM. The findings are important and provide useful insights on the impact that spatial ability and photorealistic and artistic 3D models have on anatomical education and their application to the research of instructional and assessment design in anatomy.The finding that participants with a low SA had significantly lower heart drawing scores supported our first hypothesis that learners with a high SA have superior anatomy performance in drawing assessment. The correlation between MRT and heart drawing scores was moderately positive. This corroborates with the meta-analysis by Roach et al. reporting significant positive pooled correlation between SA and anatomy performance when drawing tasks were used to assess anatomical knowledgeA possible explanation for the low SA group's performance in heart drawing is that they were unable to mentally imagine, orient, and map the heart valves with their components from an unfamiliar perspective. This impacted their ability to recall and present the image correctly. Previous research found that participants who could not draw objects from an imagined viewpoint could do it from their actual viewpointOur second hypothesis was that colour-coded 3D model would decrease ECL. Previously, literature showed that PR3DMs can provide accurate detailsPerhaps what is most important is the impact of instructional design on learning performance, as per our third hypothesis. Our results demonstrated that participants who studied the A3DM performed significantly better in post-testing than the PR3DM group, suggesting that colour-coding translated to better recognition, distinction of structures and information retention. Photorealism is useful because it preserves true geometry, giving accurate representations of subject material