Many researchers have agreed that only words and images are used in mental representation. Supporting evidence shows that memory for some verbal information is enhanced if a relevant visual is also presented or if the learner can imagine a visual image to go with the verbal information. Likewise, visual information can often be enhanced when paired with relevant verbal information, whether real-world or imagined. This theory has been applied to the use of multimedia presentations. Because multimedia presentations require both spatial and verbal working memory, individuals dual code information presented and are more likely to recall the information when tested at a later date. Moreover, studies that have been conducted on abstract and concrete words have also found that the participants remembered concrete words better than the abstract words.