our minds are highly similar to the physical stimuli. They are a near-exact representation of the physical stimuli we observe in our environment, such as trees and rivers. Symbolic codes are used to form mental representations of words. They represent something conceptually, and sometimes, arbitrarily, as opposed to perceptually. Similar to the way a watch may represent information in the form of numbers to display the time, symbolic codes represent information in our mind in the form of arbitrary symbols, like words and combinations of words, to represent several ideas. Each symbol (x, y, 1, 2, etc.) can arbitrarily represent something other than itself. For instance, the letter x is often used to represent more than just the concept of an x, the 24th letter of the alphabet. It can be used to represent a variable x in mathematics, or a multiplication symbol in an equation. Concepts like multiplication can be represented symbolically by an "x" because we arbitrarily assign it a deeper concept. Only when we use it to represent this deeper concept does the letter "x" carry this type of meaning. Support Evidence from psychological research 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. Paivio found that participants when shown a rapid sequence of pictures as well as a rapid sequence of words and later asked to recall the words and pictures, in any order, were better at recalling images. Participants, however, more readily recalled the sequential order of the words, rather than the sequence of pictures. These results supported Paivio's hypothesis that verbal information is processed differently from visual information and that verbal information was superior to visual information when sequential order was also required for