| Summary: | 博士 === 國立臺灣科技大學 === 工業管理系 === 93 === Reading from visual display terminal (VDT) is increasing enormously with widespread computer use. Whether it will affect higher cognitive processes deserves study. This first experiment explored the effect of display medium (screen vs. paper) and luminance contrast on memory performance, subjective preference and EEG response. Forty subjects performed a memory task in the experiment. The results showed that memory performance and EEG response were similar for the two display media. However, subjective preference was greater for paper than for screen and the difference was significant. Luminance contrast had significant effects on memory performance and EEG responses. Subjects showed better performance under contrast ratio 1:3 than under contrast ratio 1:15. θ-wave increase and α-wave suppression were also greater for contrast ratio1: 3 than for contrast ratio 1:15.
This second experiment investigated the effect of display medium (LCD screen vs. paper) and luminance contrast (1:3; 1:7; 1:11) on concept-formation performance and EEG responses. 96 men and 24 women participated in two concept-formation tasks (rule learning vs. attribute and rule learning) in the experiment. Concept-formation performance and EEG responses were similar for stimuli displayed on paper or LCD. The concern that LCD may be detrimental to conception-formation performance did not stand in the present study. However, luminance contrast had significant effects on time to complete a concept-formation task and EEG responses. The middle contrast (1:7) had the smallest mean EEG power, which indicated that this contrast might be appropriate for cognitive performance. It seemed that attributes of VDT such as luminance contrast instead of VDT in itself affect user’s cognitive processing. Participants’ performance was significantly faster and EEG power lower for the rule learning task as compared to an attribute and rule learning task.
Based on the results, guidelines for the optimal cognitive performance environment were suggested. The issues of display medium and luminance contrast are important because they may affect user performance and preference. The results of this study have implications for using computer in cognitive processing activities. In addition, the significant effect of luminance contrast on cognitive performance and EEG may assist in improving human-computer interaction.
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