Visual lobe shape characteristics for different subject, training, and task factors

Abstract

The relationship between visual lobe shape characteristics and search performance has long been a topic for the ergonomics researchers. It is evidenced that the quantitative visual lobe shape indexes recently developed by other researchers may provide a basis for the development of novel mathematical visual search models and serve as a useful screening device for selecting inspectors in various industries. Given the importance of lobe shape characteristics to search performance, the current study has put some effort in more in-depth understanding of lobe shape characteristics for different subject, training, and task factors with three experiments. The first experiment was to identify lobe shape differences between experienced inspectors and inexperienced subjects, the results of which will be useful for inspector selection. It was shown that the main difference between inspectors and students was found on lobe roundness and inspectors had significantly rounder lobe shape than that of students. Moreover, inspectors who had more prolonged experience in inspection jobs yield better lobe shape characteristics. The second experiment was to understand the effectiveness of different lobe shape training methods on shape characteristics and to optimize subjects’ lobe shape characteristics with the provision of shape training. The results are expected to be helpful in devising optimum training strategy for industrial operators and inspectors for daily search and inspection tasks. On this issue, it was found that although lobe shape training did not optimize lobe shape characteristics of subjects, but search task practice improved search performance in terms of search time and accuracy. Besides, the results demonstrated that lobes mapped with an easy target were larger, rounder, and more symmetric and regular with smoother boundaries than those mapped with a difficult one. The third experiment was to study the variation of lobe shape characteristics and foveal task performance with changes of experimental conditions on target difficulty, priority assignment of attentional resources, and difficulty and order of testing of foveal loading. The results will be useful in understanding the effect of information complexity processed in the central area on visual lobe shape. The results of this experiment once again showed the effect of target difficulty on lobe shape characteristics. Besides, it was shown that with the practice of lobe mapping under foveal load condition, better lobe shape characteristics in terms of roundness, symmetry, boundary smoothness, and regularity were obtained for lobes mapped under the condition of no foveal load. It was also found that directed attention onto the foveal task led to better foveal task performance. These findings were useful in devising optimum practice or training strategy for industrial operators and inspectors, which in turn will be beneficial to the high growth manufacturing and inspection environment.

Date of Award	15 Feb 2008
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Hoi Shou Alan CHAN (Supervisor)