The effectiveness of an informing system is based upon several factors that include the perceptual limitations of the person receiving the information. This paper examines the perceptual limitation of the amount of information that may be processed by the human cognitive system when this information is displayed in parallel through multiple windows. The experiments show that a sequential presentation of information is more effective than a parallel one in information transfer of large amounts of information or highly complex information in cognitively demanding subjects like mathematics. These conclusions are informative to educational system designers of complex subjects.