Effects of display medium and luminance contrast on concept formation and EEG response

Reading from a visual display terminal (VDT) has increased enormously with widespread computer use. Whether such reading affects higher cognitive processes requires study so 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 was investigated. 96 men and 24 women participated in two concept-formation tasks (rule learning vs attribute and rule learning). Concept-formation performance and EEG responses were similar for stimuli displayed on paper or LCD screen. The concern that the screen may be detrimental to conception-formation performance was not confirmed; however, luminance contrast significantly affected time to complete a concept-formation task and EEG response. The middle contrast (1:7) had the smallest mean EEG power, so this contrast might be appropriate for cognitive performance. Participants' performance was significantly faster and EEG power lower for the rule-learning task than for an attribute and rule-learning task.