Findings from Navon letters paradigm studies among individuals with autism spectrum disorder are inconsistent. The different results are often being interpreted in terms of "local bias" and/or "global weakness," according to the predictions of leading theories such as the "weak central coherence" or the "enhanced perceptual functioning." We suggest that some of the inconsistencies may be a result of differences between these studies in the stimuli's physical characteristics and/or the task's attentional demands which are known to affect the relative saliency of the global and local levels. In this paper, we systematically discuss the parameters that may affect global and local perception in autism and suggest future experimental designs and potential clinical implications of the paradigm.