Navigational User Interface Elements on the Left Side: Intuition of Designers or Experimental Evidence?

Humans tend to direct their attention toward the left half of their area of vision, which is known as visual pseudo neglect. Most navigational elements are placed at the left side. However, there is neither a theoretical reasoning nor empirical evidence, why these elements should be placed left. In the present study we examined three independent variables (presentation side of elements (left, right), number of elements (one, three, five) and a visual cue prior to selection (with cue, without). Dependent variables were selection times and accuracy of task completion. 50 participants were exposed to elements consisting of single words in bubbles. After clicking on the start element in the middle of the screen a number of elements were presented randomly on the left or right. In 50% of trials the presentation side was announced in advance, by using a visual cue. It was tested, whether and to what extent there is a preference and performance (correct selection time) increase for elements placed on the left side. When the cue was presented, performance increased; without cue information, elements on the left were selected faster. The use of cues resulted in no significant differences between the left and right side. A significantly better performance was found when only one element was presented on the left. With an increasing number of elements, the performance decreased. The results of this study suggest that the presentation of elements on the left side is advantageous for the speed of information processing only in the case of single elements. When selecting between numbers of options (three, five), placing elements on the left does not affect the selection performance.