Imagery, Keyword Mnemonics and Dual Coding Theory
The learning strategies considered by Weinstein and Mayer (Table 1) - rehearsal, elaboration, organization, comprehension and affective - are general categories of strategies which need to be considered for effective teaching. Table 2 summarizes six strategies which have been proven to be successful in the classroom - imagery, elaborative interrogation, acronyms, keyword mnemonic, summarizing and concept mapping. Imagery and elaborative interrogation appear to be examples o
f Weinstein and Mayer's elaboration category, while acronyms are organizational in nature. Keyword mnemonics, summarizing and concept mapping fit elaboration and organization categories. Imagery was specifically chosen for detailed consideration because it appears to be a more fundamental strategy than the others, and an essential component of keyword mnemonics.
Representational imagery involves creating a mental image linking information to be remembered. For example, creating an image of a hockey player skating on spaghetti as a way to remember to bring food for an after-the-game party. Chemistry students needing to remember to remove the tops from test tubes in which reactions are taking place may create images of themselves jumping up and down inside the test tubes. An image of a tree with tan-coloured leaves falling on its shadow may remind mathematic
s students that the tangent angle is calculated from the length of the tree divided by the length of the shadow. A geology student with a mental image of mountains of dirty dishes piled high at home may remember that one of the results of plate tectonics is mountain building.
Seifert and Lake (p4) suggest that their study provides strong evidence that imagery training can enhance young children's memory for simple prose. "When children are taught to imagine single objects and pairs of objects interacting, they are able to utilize these skills for remembering simple prose sentences"; as the hockey player on spaghetti. Their study follows Paivio's work of 1970 in which he determined that "... performance on a variety of memory tasks was improved when subjects generated ima
ginal representations of the to-be-remembered material" (Pressley, p355). For example, in the experiment performed by Pressley, in which students were given practice constructing mental images of progressively longer prose passages (sentences, paragraphs and a short story), students who were shown slides depicting the meaning of sentences scored higher on testing than the control group. This led Pressley to conclude that "... mental imagery training can be easily taught in the classroom and improve child
ren's memory of passages they read" (p358).
The relationship between text and image as elements of the encoding process is called dual coding theory. This theory suggests that "by generating images of verbal information, including illustrations with text (pictures or mental images), or by elaborating upon illustrations with explanations, the likelihood that both systems are activated is increased, that information is encoded in verbal and non-verbal form, and memory should be enhanced" (Seifert, 1995, p4-5). For dual coding to work, images m
ust be representational; meaning that they must actively draw attention to links within the new information, or between new information and prior knowledge. Seifert (1995, p4-5) suggests that "in making a mental image of some information, the student must identify important ideas and relate those ideas. That is, the image contains both the concepts to be learned and the relationships between those concepts."
Pressley also concluded that "... many children spontaneously used mental images when presented concrete prose passages. ... [and that the] difference between experimental and control subjects may be small because the control group was imaging spontaneously" (p358). Imaging spontaneously may be a function of experience because Seifert and Lake (p1) suggest that "... prior knowledge may play an important role in the extent to which students may benefit from the use of imagery to remember information."
Weinstein and Mayer (p319) suggest that "... younger children are not able to effectively generate images but are able to use imagery that is provided by a teacher; in contrast, older children who are able to generate their own idiosyncratic images may be distracted by the teacher's imagery suggestions." Based on this conclusion, they propose that imagery strategies could be divided into two categories: induced - "in which the learner is instructed to generate and use visual imagery to associate items"
; and imposed - "in which the experimenter or teacher provides an image and asks that the learner use the image to associate items" (p319).
As opposed to imaging spontaneously, the strategy of keyword mnemonics involves the active generation of more complex pictures in which two or more concepts are linked by their visible interaction. "The keyword method involves identifying a new word or name to be
learned, transforming that word into a familiar sounding word, and then generating an image of the new word and old word interacting" (Seifert, 1995, p4-9). Peters and Levin conducted a study to determine if children of different reading abilities could benefit from a memory-enhancing imagery strategy. In their experiment students recorded a "famous" person's surname into a keyword, and then created a relational image between the keyword and the person's accomplishment (p180). For example, the name, occ
upation and claim-to-fame of their famous fictional tailor, Larry Taylor, who invented a house-on-a-turntable designed to rotate for exposure to the sun, was accomplished by imaging his house on an elevated turntable, the base of which was decorated by a curtain Larry was sewing. Carney et al. wanted to discovered if students could be taught to associate artist names with their paintings. For example, a painting by Millet entitled "Man with hoe" was remembered by mentally transforming the hoe into a croq
uet mallet, and linking from mallet to Millet (p109).
Levin et al. (p280) represented four separate concepts - wealth, natural resources, technology and a growing population - by simple illustrations of money, an oil well and storage tanks, a computer terminal and a crowd of people. The separate illustrations were then combined into a single organized picture in which people were shown standing around an oil well while either holding money or typing at a computer keyboard. Hence "mental" links were created visually to stimulate the encoding process. I
n addition, by showing the oil well and tanks covered by frost, their organized picture could be associated with the town of Fostoria.
Wittrock, in developing generation theory, was also interested in how learners used imagery to construct meaning. He examined whether or not using pictures could enhance generation, and concluded that readers who could not generate links otherwise should be given "pictures, diagrams, graphs and the like" (p368) to show relationships. He suggested that pictures processed an important interactive quality - the ability to show relations among the parts they juxtapose. He suggested that teachers need t
o teach students the construction of interactive images as a way to facilitate memory and comprehension (Wittrock, p371).
My interest in imagery relates to the concept of guided imagery (Egan, p61), or Weinstein and Mayer's (p319) teacher-provided category, in which the images are stimulated in students. For example, a teacher may tell a story which causes students to link to prior knowledge and supply such details as sights, sounds, tastes and smells. However, an imagination trap springs when teachers extend story by supplying too much supplementary material. For example, showing an illustration of a widget before st
udents try to create their own drawings would influence their construction and use of prior knowledge. Indeed, the simple exercise of asking a student what his / her imagined picture looked like will influence the thoughts of all the other students in a class. And in today's classroom, one tool which may become an imagination trap for many students is the multimedia computer.