In this study, the author investigated factors that influence the direct measurement of cognitive load using the dual-task method. The dual-task method is an unambiguous and objective technique to measure cognitive load. The primary task was to master content in a lesson about the Autonomic Nervous System. The secondary task was to respond to a symbol that changed colour by pressing the Enter key. The time between the symbol changing colour and the response of the student was measured. Two versions of the multimedia program tested the influence of the presentation format and instructional strategy on cognitive load. Each version of the program was further subdivided into four lessons, which were used to test the influence of the position of the secondary task on the cognitive load. All the data was collected electronically. The statistical analysis revealed that the position of the secondary task does not influence cognitive load (F (1, 2661) = 3.25, p = 0.071). The presentation format and instructional strategy used in this study however did result in a significant difference between the cognitive load of the two versions. The mean cognitive load of the version using animation was 6.408 and that of the version using predominantly static images and text was 5.684. This difference was found to be highly significant (F (1, 2661) = 52.39, p <.0001). It was concluded that using animation to present content required more mental effort by participants than using images and text to present the same content.