The role of trait impulsivity in response inhibition: event-related potentials in a stop-signal task.

The study examined the relation between self-reported impulsivity and inhibitory control in normal individuals. We compared stopping performance and neural correlates of stopping on stop-signal task between participants who scored in the top (n=12) and bottom 25% (n=12) on Impulsivity Scale from a sample of 305 male adults. Participants scoring high on impulsivity did not show impaired inhibitory control. However, it seems that the high impulsive tended to make more errors of commission and omission. Enhanced N1 amplitudes were found in successful than failed inhibition trials. The high impulsive group had smaller P3 amplitude than the low impulsive group. It appears that the high impulsive group may have a less efficient inhibitory control. Impulsivity Scale non-planning impulsiveness score and inattention score of Adult ADHD Self-Report Scale (ASRS) were negatively correlated with P3 amplitudes on successful inhibition trails, suggesting that impulsivity could have the potential influence on inhibitory control.

Preferred viewing distance of liquid crystal high-definition television.

This study explored the effect of TV size, illumination, and viewing angle on preferred viewing distance in high-definition liquid crystal display televisions (HDTV). Results showed that the mean preferred viewing distance was 2856 mm. TV size and illumination significantly affected preferred viewing distance. The larger the screen size, the greater the preferred viewing distance, at around 3-4 times the width of the screen (W). The greater the illumination, the greater the preferred viewing distance. Viewing angle also correlated significantly with preferred viewing distance. The more deflected from direct frontal view, the shorter the preferred viewing distance seemed to be.

Color combinations of visual display terminal (VDT) icon on user preferences and EEG response.

This study explored the effects of color combinations and polarity on user preferences and EEG responses using an icon design for a visual display terminal. 72 college students (M=24.5 yr., SD=2.3 yr.) were tested. The seven color combinations of top 16% with rating scores (5-point scale) over 3.60 almost always included black or white as a target or background, including white-on-black, red-on-black, yellow-on-black, blue-on-white, and black-on-white; the other two preferred color combinations were yellow-on-blue and blue-on-yellow. The eight color combinations of the bottom 16% with rating scores under 2.38 almost always included green, turquoise, or purple as a target or background. Negative image polarity (higher luminance color image shown on a lower luminance color background) was preferred over positive image polarity (lower luminance color image shown on a higher luminance color background) by the subjects. The theta and alpha band power in the right hemisphere were greater than those in the left hemisphere during the experiment. There seemed to be no linear correlation between the rating scores of subjective preferences and brain wave power of theta and alpha bands, so the possibility of using brain wave power to measure subjective preference is questionable.

Preferred viewing distance and screen angle of electronic paper displays.

This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 495 mm and 123.7 degrees. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4 degrees, significantly greater than that of Sony, 120.0 degrees. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7 degrees, which in terms of viewing angle is 29.5 degrees below horizontal eye level. This result is similar to the general suggested viewing angle between 20 degrees and 50 degrees below the horizontal line of sight.