Perception, imagery, visualization and engineering graphics

We have conducted action research involving an instructional intervention over a 20-year period. This has demonstrated that spatial ability influences academic performance in engineering, and can be increased through instruction focused on using perception and mental imagery in three-dimensional representation. Prior to our intervention, the first-year engineering graphics course at our university had a failure rate of 36% for all engineering students and failure rates of 80% for African students studying at our university. Similar high failure rates were reported in engineering drawing and design courses at other Southern African universities, and similar association between low scores on tests of spatial ability and academic performance, suggesting that the problem was one encountered by many engineering students, not just by students at our university. Over the initial 2 years of the intervention, pass rates for the first-year engineering graphics course increased from 64 to 76%. With further changes in teaching, and the training of senior students as tutors to support the lecturing and practical activities provided in the course, the pass rates have risen to 88% annually, over a period in which the composition of the first-year student has become increasingly diverse, with greater numbers of students entering the university from disadvantaged educational backgrounds. The instructional model we have used is based on Piagetian principles, and confirms Piaget's theories with respect to the trainability of spatial ability in adulthood. Our findings suggest the importance of early identification of students with difficulty, as well as the potential value of an intervention aimed at training the processes involved in visualization through three-dimensional modelling and representation of objects. While spatial ability appears to be trainable through the methods we have developed, our research also indicates that level of spatial ability at time of intake to university is an important influence on academic performance, suggesting the value of instruction in visualization and three-dimensional representation at school level. Social factors are also important influences on academic performance, suggesting the value of tutorial-based interventions aimed at improving spatial ability in those university and technikon courses for which visualization and three-dimensional representation are a requirement.