A working memory capacity (WMC) test called “objects-span tri-tasks” is designed for preschoolers undergoing treatment using a new genre of multimedia, tangible multimedia, created by the authors. It tests the dual-functions of the preschoolers’ working memory (WM), namely storage and manipulation capacity, essential in supporting academic skills. The third task in the test is the overt setting of task engaging the long-term memory that supports the operation of WM. Tangible multimedia potentially enhances the WMC of preschoolers to a considerable extent because firstly, it uses tangible objects that are cognitively appropriate to the “preoperational” stage of preschoolers, and secondly, it simultaneously stimulates three main sensory channels, prescribed as equally crucial in knowledge acquisition in human memory theories. A pragmatic significance of the research is that it deepens the scope of multimedia research by looking into the aspect of cognitive structure wh