The effect of icon spacing and size on the speed of icon processing in the human visual system

Alphanumeric and graphical information needs to be presented in such a way that its perception is accurate, fast and as effortless as possible. This study investigated the effects of spacing and size of individual interface elements on their perception. Experiment I investigated the effect of icon spacing on the speed of visual search for a target icon and determined the perceptual span for icons, that is, the number of icons that can be processed by one eye fixation. Experiment 2 studied the effect of size, and experiment 3 the subjective preferences for levels of icon spacing. The results of experiment 1 showed that spacing does not have an effect on search times. On average the perceptual span for icons was found to be 25 arranged in a 5 X 5 array. The size of the inter-face elements, on the other hand, was found to have a great effect. Icons smaller than 0.7degrees resulted in significantly raised search times. Experiment 3 revealed that an inter-element spacing of one icon is to be preferred and a spacing of zero icons is to be avoided. (C) 2003 Elsevier B.V. All rights reserved.