By John Sweller
"When technology is used to present information to learners, the modality and format of the presentation is frequently changed. For example, written information may be substituted by spoken information and the static graphics associated with hard copy may be replaced by animations. While instructional designers are usually highly cognizant of these changes, there is another, concomitant but less obvious change that occurs. Relatively transient forms of information such as speech or animations replace a relatively permanent form of information such as written text or visual graphics. Frequently, this change is treated as being incidental and is ignored. Cognitive load theory suggests that it may be critical. Limited human working memory results in transient, technology-based information having considerable instructional consequences, many of them negative. Theory and data associated with the transient information effect will be discussed in relation to e-learning."