Memory

Graphics, diagrams, and videos are frequently used to enhance learning of verbal material. Indeed, as much as half of the space in K–12 textbooks is devoted to graphics and diagrams, and videos are frequently presented in classrooms. Furthermore, recent technological advances have made possible the use of additional, primarily visual, materials for instruction, such as animation and hypertext.

Presumably, graphics, diagrams, video, and other visual materials are used to make information accessible and memorable. But how might such visual materials be exploited to facilitate learning and memory? When are such displays actually beneficial for learning, and when are they simply decorative or even distracting? This brief review begins with a discussion of general research on how visual media displays aid comprehension and enhance memory for verbal material, and the circumstances in which visual materials are distracting and perhaps even reduce comprehension memory of verbal material. This discussion incorporates guidelines for the design of visual displays for effectively enhancing memory in the context of specific commonly used displays such as graphic organizers, graphs, diagrams, and videos.

Main Benefits of Graphics, Diagrams, and Videos

Visual displays and videos play a number of important roles in learning. Perhaps the most cited cognitive explanation for the benefits of presenting information both visually and verbally is Allan Paivio's dual-coding theory. In classic memory studies, Paivio and his colleagues demonstrated that people were better at remembering lists of words coded visually and verbally, rather than merely verbally. One explanation for the superiority of dualcoding is that by encoding information to be learned in two modalities rather than a single modality, people have multiple retrieval cues that help them access information, thus enhancing memory.

A second general benefit of visuospatial displays is that they are visually appealing. Viewers' attention is attracted to these displays, and viewers are more likely to study them for longer periods of time. This, in turn, can lead to enhancement of memory for information depicted in them. For example, one study of memory for materials taught in introductory psychology courses found that students recalled ideas and examples presented in videos and in-class demonstrations better than information presented in the text alone.

In addition to directly enhancing memory for information, diagrams, graphics, and videos can also make complex information easier to comprehend. Specifically, visual representation can make complex information "visually obvious" and thus require less cognitive effort to understand than text-based descriptions of the same information. Better comprehension, along with more cognitive resources that can be allocated to learning and memory, will together enhance memory for the information to be learned.

Concepts that Visual Displays Are Most Useful in Communicating

Visual displays are particularly beneficial to the comprehension of some classes of concepts that often involve specialized types of displays. First, visual displays are useful for communicating cause- and-effect information. For example, a diagram can help illustrate how turning a key can unlock a door. When such displays are designed to highlight the cause- and-effect sequence (e.g., by animating one portion at a time or by using a sequence of arrows), viewers' comprehension and memory for the cause- and-effect information is enhanced.

Second, visual displays are frequently useful for representing relationships amongst elements (e.g., a Venn diagram, a text-based graphic organizer, a scientific model). One benefit of such representations is that they can facilitate problem solving. Another benefit is that they provide concrete representation of key concepts or elements and their relationships. Graphic organizers, for example, are often used to represent relationships among the main ideas in a text. For example, information in a text can be summarized in matrix form such that similar concepts are closer together along one or more dimensions. Research has suggested that representations that group relevant concepts, such as matrices, can significantly enhance memory for text compared to representations that simply summarize materials, such as outlines. Indeed a general principle that is relevant for any diagram intended to represent relationship elements, including graphic organizers but also including graphs, flowcharts, and so on, is that information that is closely related be placed close together on a page or related visually (e.g., via Gestalt principles of grouping).

Third, visual displays are useful for communicating information that is intrinsically visuospatial. For example, visual displays of a map of a building or a drawing of how different parts of a car engine fit together communicate information that is difficult to describe verbally. Not all intrinsically visuospatial displays, however, are equally beneficial. One general guideline is to design displays that facilitate integrating relevant information (placing text and graphics together) to reduce working memory load and allow viewers to focus on learning relevant content. A 2001 book by Richard Mayer on multimedia learning includes a number of guidelines for the design of such displays.

Fourth, visual displays provide natural mappings to quantitative information (e.g., more is higher) and thus increase comprehension and memory for quantitative information. One difficulty associated with graphs is that students often make interpretation errors and therefore remember erroneous data. In a 2002 article, Priti Shah and James Hoeffner discuss a set of guidelines for teachers and other graph designers who need to depict data for students. These guidelines include making relevant trends visually salient in the graph and writing text to be compatible with information in the graph.

Additional Benefits of Visual Displays

In addition to making some concepts easier to understand, diagrams, graphics, and videos tend to focus viewers' or readers' attention and thus highlight important information. Displays or videos can guide a viewer's attention from one step to the next in a description of causal information or in instructions. For example, a sequence of arrows might highlight how a mechanical device, such as a bicycle pump or a toilet, works, or a sequence of panels might instruct someone how to bake cookies. Such displays, by highlighting information or key elements in a sequence, help students learn and remember relevant information.

In addition to the cognitive aspects of how they influence memory, visual displays and videos serve a social function beneficial to memory. In particular, visual displays and videos provide a common motivating experience for students. In "anchored instruction," students view movies with built-in problems that serve as a reference point for lessons on a wide variety of topics such as solving mathematical problems, discussing social issues, and understanding physics concepts. The common anchor may provide a social and personal context for information to be learned.

The use of graphics, diagrams, and videos includes not just presenting such visual information to students but also asking them to create them. Creating visual artifacts or inscriptions appears to be motivating to students, especially when they share their products with fellow students. Furthermore, developing them forces students to consider the important elements and relationships and also to identify what information they understand and what they do not. Thus, the creation of graphics, diagrams, and videos can be used to enhance comprehension and memory for to-be-learned information.

Drawbacks of Displays and Videos

Despite the benefits of graphics, diagrams, and videos for helping students comprehend and remember important information, there are some cases in which displays and videos can be harmful. Specifically, because graphics, diagrams, and videos attract attention, it is possible that in many cases such visual presentations serve as seductive details detracting attention from important information and thus impair rather than enhance learning. A concrete example of a display that may serve as a seductive detail is a picture, in a scientific text about how lightning is formed, of someone who was struck by lightning. Although the intention of such a picture might be to interest the students in the content of the text, research has found that, in fact, displays such as these are actually distracting and reduce the quality of readers' understanding of the scientific content of the text. Videos, also, can serve as or include seductive details detracting viewers from the main message of a particular lesson.

In summary, this general discussion of visual displays suggests that diagrams, graphics, and videos can help users comprehend relevant information and enhance memory for that information. The content and format of the information, however, should be consistent with the goals of communication. When the content is not consistent with the goals of communication, students may remember irrelevant or inaccurate information.