The Use of Analogies as a Constructivist Approach in Science Education
When I was teaching high school, I frequently found myself and my students using analogies to convey distant ideas in terms the rest of my/their audience could understand with minimal exposition.  I grew interested in formalizing this device as an actual method, so I sought to understand some of the theoretical base on which such an approach my be founded.  The following paper was written 7/2000 as part of an independent professional development project.



TABLE OF CONTENTS

Abstract

This paper attempts to explore the use of analogies as a constructivist-based method in science education.
The paper begins with a survey of how analogies might be viewed through various educational theories.  Next, analogies are classified according to structure and appropriate usage.  Finally, some observations are made on the practical implications of using analogies in the classroom.

Because this paper focuses on science education at the secondary level, many of the observations and examples drawn from content are appropriate to this age group.  The majority of the examples of analogies included in this paper are drawn from the realm of biology or chemistry.  Regardless of the context, this approach as well as the underlying theory have applications in all levels of education.


Chapters

I INTRODUCTION
    Statement of problem
    Purpose
    Assumptions
    Limitations

II RESEARCH PROCEDURES
    Rationale for a Qualitative Design
    Setting

III REVIEW OF RELATED LITERATURE
    Defining the Analogy
    Problems with Analogies

IV THE PLACE OF ANALOGIES IN EDUCATIONAL THEORY
    The Role of Analogies in Language and Learning
    Connection to Constructivism
    Connection to Brain Research
    Connection to Piaget's Model of Learning
    Connection to Piaget's Stages of Cognitive Development

V ANALOGIES CLASSIFIED
    Similes
    Itemized analogies
    Anecdotal analogies

VI USE OF ANALOGIES IN THE CLASSROOM
    Employing a Constructivist Approach
    The Importance of Prior Knowledge
    Multiple Intelligences
    Analogies as Modes of Assessment
    Overextension of Analogies

VII SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
    Summary
    Conclusions
    Recommendations

REFERENCES


I INTRODUCTION

Statement of problem

Much of the literature on the subject of analogies reflects the notion that analogies are one narrowly defined means of relating two apparently unrelated entities through itemization of their similarities.  If all types of analogies are viewed as the same, phenomena specific to each type of analogy may be reported in the literature in the same data set.  This overlapping data may then be compared erroneously, giving the false impressions of the nature of analogies and their use in the classroom.


Purpose

This paper attempts to explain the use of analogies through several educational perspectives.  Next, this paper seeks to make the point that analogies exist in a plethora of forms across a spectrum of possible approaches one (be it instructor or learner) might use to make sense of unfamiliar concepts.  Once these categories of analogies are established, this paper goes on to provide some guidelines for using analogies in the classroom.


Assumptions

It is assumed that the majority of readers would be unfamiliar with those scientific concepts which would most likely require analogies in their instruction.  For that reason this paper dedicates much more emphasis to reviewing literature on the subject of analogies than might be expected in a journal dedicated to methods of science teaching.  This literature is intended to make connections between various competing and complementary families of pedagogical theory and philosophy, much in the way analogies attempt to connect new concepts to familiar understandings.


Limitations

Because there is only one section of each course described in this paper, it is difficult to conduct a traditional type of study in the ACT Academy.  No control group can be isolated without compromising the quality of the educational situation, so no means of generating comparison between cohort groups presents itself.  Instead, this paper offers a comparison between different classes over the course of two years and examples of the learning generated in each.  This is as much a record of facilitator learning as it is a study of the effectiveness of a particular approach in promoting learner understanding.

II RESEARCH PROCEDURES

Rationale for a Qualitative Design

The dominant mode of research in the area of analogies in science education has been quantitative in nature (Thiele and Treagust, 1994).  This paper continues in that approach owing to the fact that analogies are difficult to quantify except in, for example, the length (in number of words) or the frequency of use. Quantitative methods fall short in estimating the qualities of a given analogy in terms of its appropriateness in explaining a given topic conceptually and its effectiveness with a given population of learners due to a connection to their prior experiences and/or their degree of cognitive development.  Thiele and Treagust (1994 after Friedel et al., 1990; Gabel & Sherwood, 1980) point out that "analogies may be ineffective... if the analog is unfamiliar to the students and if the students are not at the developmental stage were they have the necessary visual imagery and analogical and correlational reasoning skills" (p.328).  No classroom, particularly not one in an integrated environment such as the ACT Academy, has a perfectly homogeneous population in which any given analogy can be considered uniformly effective in fostering understanding across individuals.


Setting

The ACT Academy is a K-12 school of approximately 250 learners.  The school is organized into the three expected levels: elementary (K-5), a Junior Institute (6-8), and a Senior Institute (9-12).  Cross-age learning is promoted.  However, core courses (science courses included) are generally not involved in these approaches.

The classes from which observations were drawn for this paper included:
Chemistry: 1998-1999.  Eight learners representing grades 9-12.
Chemistry: 1999-2000.  18 learners representing grades 10-12.
Biology:  1998-1999.  16 learners representing grades 9-11.
Biology:  1999-2000.  17 learners representing grades 9-10.
Medical Science II (Anatomy & Physiology): 1998-2000.  17 learners representing grades 10-12.

As this school is not zoned (that is, learners come from all parts of the district), learners vary in ethnicity and socioeconomic status.  Gender bias was negligible except in the 1999-2000 section of Biology in which there were only 3 females to 14 males.


III REVIEW OF RELATED LITERATURE

Defining the Analogy

According to Lawson (1993) "the central goal of science is to develop satisfactory explanations for natural phenomena."  The pursuit of the unknown may or may not require specialized detection equipment such as a telescope or a Giger counter, but the understanding that follows from the detection is another matter entirely.  For many years after Galileo observed the heavens understanding of his heliocentric (literally, "sun-centered") model of the solar system could not be fostered among the general populous.  The problem was complex, but a part of the issue at least was that this idea was too abstract to be grasped.  A device was required to bring about learning.

An analogy is anything which likens something already known and understood to something less completely understood.  Webster defines an analogy in several ways.  The one which applies to the discussion here is:
 a: resemblance in some particulars between things otherwise unlike.
 b: comparison based on such a resemblance.
These definitions take an objectivist stance, implying knowledge lies outside of the mind.  In fact, analogies serve to tap into what is known and connect that to the new and unfamiliar.

Analogies are in many ways a taken for granted feature of science.  Models, either physical or diagrammatic are frequently, and even names are are derived from comparisons of entities otherwise unlike (in the scientific sense), for example, the "tiger" shark is so named because its stripes resemble those of a tiger.  This serves to make a concept more available to the memory by relating something real and in the more common experience to something perhaps more abstract or otherwise less accessible.


Problems with Analogies

The effectiveness of analogies, like that of physical models, begins to break down as inspection draws closer to the limits of the analogy's accuracy.  Wong (1993a) warns that "all analogies are faulty in some respects and that no analogy will completely and accurately represent the nature of the phenomenon" (p.1262).  Just as one cannot dissect a plastic frog and find realistic organs (not usually, anyway), analogies cannot be scrutinized beyond that for which they are intended to illustrate.  Learners do have a tendency to overextend their learning, so the realistic parameters of the analogy must be addressed during the course of any discussion involving one.  Wong goes on to suggest that, as a precaution, multiple analogies be employed to compensate for the deficiencies inherent in each as well as the varying interpretations generated for each learner.

IV THE PLACE OF ANALOGIES IN EDUCATIONAL THEORY

Many theories currently compete for the most accurate explanation and/or predictor of the learning process.  Regardless of the angle from which the instructor chooses to perceive the process, analogies are useful tools in fostering new learning by connecting the unfamiliar to existing knowledge.

The Role of Analogies in Language and Learning

Because analogies are such a significant feature of language, the uses and features of language must be considered in any discussion involving their use in any setting.  Sutton (1993) states that "analogy and metaphor are customarily regarded as part of a special kind of language, separate from what we take to be ordinary speech, which we use to exchange information and to describe things in factual, literal ways" (p.1215).  He goes on to suggest that this separation gives learners a "false idea of language and its role in scientific understanding" (p.1215).

Sutton (1993) goes on to show how figures of speech are employed in scientific discourse to communicate understanding.  For example, Darwin used a metaphor to describe the branching process of evolution as creating a "great Tree of Life" (cited in Sutton p. 1217).  Similes are also used to elaborate understanding as in James Hutton's comparison of the earth being "like the body of an animal" (ibid).   As products which offer greater elaboration, Sutton goes on to show how models can be used to give a point by point analysis of a phenomenon as in the "lock and key" analogy of enzyme-substrate interaction found in nearly all texts which deal directly with the concept.

There are numerous other taken-for-granted examples of the adaptation of elements of existing language to describe new phenomena.  Often the novel concept had little in common with the terms conscripted to construct their description.  For example, heat and electric current are both said to flow, though neither have the physical presence in the same sense as air or water.  Other common examples include biochemical "pathways" and  "heat sinks," both of which allude to physical entities to describe abstractions.

Self-generated analogies can and do occur spontaneously in discussion.  There is no requirement that one ritualize the approach in order to communicate a scientific phenomenon.  Language is of course the currency of social exchange.  Social interaction is considered by many theorists (Vygotsky most famously) to be the medium in which learning is constructed.  The role of analogies in the constructivist approach is explored now.


Connection to Constructivism

If one were to attempt to explain constructivism, not only might analogies by used as examples of how one learns, they may in fact be better used to describe the theory of the constructivist approach itself.  My first encounter with constructivism came in my first education class in college, in which we read a book called The Construction Zone.  The professor explained the philosophy the book espoused as "building knowledge on a site where knowledge already exists."   The analogy implies that, just as a builder would not attempt to build walls before pouring a foundation nor to construct a roof without completing the walls, so should educators try to add new structures on solid ground.

Wong (1993b) states that "students need to develop the ability to identify and represent scientific phenomena in a manner that enables them to gain a greater understanding on their own" (p.369).  Analogies facilitate constructivism's core dictum by bridging the gap between what is already understood and what is as yet unlearned.  Prior learning serves as a foundation for new encounters with similar material (even if that knowledge is from an unrelated discipline or no academic discipline at all).

Up to this point analogies have been discussed as isolated entities.  Analogies may be presented to the learner as prepared elements of a lecture or they may be generated by the learners themselves.  Wong (1993b) finds that "constructing one's own analogy serves to (a) make new situations familiar, (b) represent the problem in the particulars of the individual's prior knowledge, and (c) stimulate abstract thinking about underlying structure or patterns" (p.377).

Further, the fact that learners have generated analogies that are are likely far from ideal may promote greater learning than textbook examples.  Wong (1993a) points out that learning from analogies comes from the differences as well as the similarities between the phenomenon under study and its analogical counterpart.  The interactive, social process of exploring analogies, whatever their source, contributes to this learning process.


Connection to Brain Research

Despite the mythology surrounding brain research, it is not terribly difficult to understand the mechanism of the analogy in neuroscientific terms.  Structures in the brain are formed around (or to create) meaning.  In order to extend that meaning the learner must add to the existing structure.  When new structures are formed in isolation (i.e. "from scratch") meaning is not only tentative at best, the structure itself has few connections to other parts of the brain.  Not only is it difficult to access information from the perspective of pure recall, there also may be few connections to other knowledge and abilities.  In this scenario knowledge likely remains at the lowest rung on Bloom's taxonomy, unable to be applied or used in any way outside of the context in which it was covered (one of the findings of an analysis of why American students performed so poorly on the TIMSS).

In traditional educational approaches facts are often emphasized at the expense of the relationships between those facts.  Unrelated facts are, of course, difficult to store in long term memory, so much is lost.  However, if those facts are related (i.e. "chunked" together -terminology after Miller) they can be retained for a significantly greater duration.

Lawson and Lawson (1993) provide a neural model as to how analogies provide this mechanism.  According to their model, not only is new understanding of a scientific concept built upon its analogy, the physical substrates in which these conceptual entities "reside" are built one from the other.  Rather than building an entirely new structure in order to develop understanding, analogies use existing structures with similar features or internal relationships.  According to Lawson & Lawson (1993) this reduces the amount of time required for learning to occur and enables the new structure to be reinforced in its early stages (whereas, without the presence of the analogy, the structure might still be forming and miss opportunities for reinforcement.

Returning to the topic of language, even mnemonics rely on this underlying neurobiological mechanism that makes the use of analogies effective in promoting learning.  For example, ROYGBV (pronounced "Roy-G-Biv") effectively chunks the sequence of colors in the visible light spectrum.  From this "chunk" of neurons, connections to the names of the colors are made.  The naming of a sequence of colors is relatively abstract, so most mnemonics appear to reach more for anecdotal qualities such as "my very energetic mother just served us nine pies" for the sequence of planets in our solar system or "King Philip came over for great spaghetti" for the bottom-up hierarchy of the common taxonomy classification system (kingdom, phylum, class, order, family, genus, species).  These tools successful because they play upon our preference for language over unrelated sequences of data (which will be discussed in more detail later).  In relying on this same neurological mechanism employed in making use of more traditional analogies it could be argued that these tools are cousins to analogies if not analogies by definition themselves.


Connection to Piaget's Model of Learning

In Piaget's model (Fig. 1), true learning can come about only after several internal hurdles.  First, the mind must filter and sort through extraneous stimuli.  If the mind of the learner is not engaged in the material, the encounter will not result in learning.  Good analogies begin by bring learners into the realm of attention by relating new learning to features of the learners' own experiences.  This can be maximized still further (as pointed out easier) when learners generate their own analogies.  For example, a learner attempting to understand the nature of ecology may draw from his or her understanding of the complex communities on the internet to create connections to new material.

Figure 1: Piaget's model of Learning

 
 
->discarded
stimuli->
disequilibrium->
->assimilation
 
 
->accommodation
 
There is potentially a link to emotional intelligence here in that learners will often offer up examples to which they are emotionally attached (i.e. skateboarding, favorite movies).  Brain research indicates that strong emotions (positive ones) help tie new learning down.  They serve as a neurological "glue" to maintain memories of certain stimuli (Wolfe and Brandt, 1998).

Next, information causes what Piaget described as disequilibrium.  In his view new knowledge must cause a shift (however temporary) in the patterns which existed before the stimulus.  If this stimulus does not make "sense" to the learner it will be discarded.  However, if the learner can understand the stimulus in relation to something previously understood, the stimulus now has a chance of finding a "home" among other meaning.  Analogies bring us to this point by starting with something familiar to the learner, thereby diminishing the disequilibrium.

However, there are two ways in which information (whether in the form of facts or skills) may be "written" to the brain.  One is called accommodation, which is more tenuous, in which information is stored in a new part of the brain.  The other is called assimilation, in which new knowledge is attached ("filed among") existing knowledge.  This gives new knowledge a more permanent hold in the mind and a greater easy of accessibility.  Because analogies start with the familiar and more firmly establish

Beginning a unit of new content with material familiar to the learner can overcome two of the difficult points in Piaget's model of learning.  Disequilibrium is alleviated by beginning understanding from an established structure in the brain.   Next, learning will proceed from this foundation, allowing new learning to have a seed from which to germinate rather than requiring the learner to build new understanding from little existing knowledge.


Connection to Piaget's Stages of Cognitive Development

It is possible that the effectiveness of analogies has a second connection grounded in Piaget's work.  Piaget's the last stages of cognitive development involve learners moving from the ability to operate concretely to a more abstract mode.  This usually occurs in the secondary years.  However, not all learners develop at exactly the same rate (and arguably some never achieve the final stage in any complete sense).  However, schools are organized largely by age and not necessarily by cognitive achievements.  This creates a problem for the instructor who is now required to develop lessons addressing the cognitive needs of learners in both of the latter groups.

Analogies provide some aid in working around this issue while engaging both groups.  As abstract concepts are discussed throughout science courses, many learners still operating in the concrete stage of development may be lost by a failure to attach understanding to anything of substance.  This can be especially profound in the chemistry classroom where microscopic, invisible entities are the primary topic.  Analogies bring abstract topics into the macroscopic realm by providing examples most learners can visualize and mentally manipulate.

This implies that, in order to be effective, the analogies should refer to elements or situations in the physical world, things that are real and experienced.  If fact, Wong (1993b, after Petrie, 1979 and Schon, 1979) recommends that analogies "engage in concrete activity with the phenomenon:  Sensory activity may stimulate associations that are not yet possible through abstract, verbal means" (p.370).


V ANALOGIES CLASSIFIED
Analogies are generally "clumped" together in the literature, regardless of form.  This may serve to misinform the profession who believe that analogies are all of equal applicability in educational situations, when, in fact, they are not.  One exception to this assertion is Thiele and Treagust's (1994) system of simple, enriched, and extended analogies.  This classification, however, does not address the appropriateness of use according to pedagogical need.

In my experience there are at least three types of analogies.  Although they are distinct, each can serve several overlapping instructional purposes.  The labels assigned to each of these categories are intended as the simplest description and do not imply any overarching theory to explain how each category was generated.  These categories are presented in increasing order of complexity.

Similes (aka proportional analogies, Wong, 1993)

The first and simplest type is the simile.  Generally this type is offered as an aside in which something is used to relate only one aspect of a concept or object to that which is under study.  Because of its simplicity this type is most frequently used conversationally.  However, this simultaneously makes it both the easiest and most difficult to use with low performing learners.

Similes may be a natural feature of language, but they are rarely used in the logical/mathematical "A is to B as C is to D" format one might find on standardized tests such as the SAT.  This format draws attention to exactly which features of the respective overall concept or physical entities are being compared.  This could confuse a learner who does not intuitively organize information in this manner.  Here is an sample exchange:

INSTRUCTOR:  DNA contains the instructions for building your body

LEARNER #1:  Like a blueprint!

INSTRUCTOR:  Yes, that's right.

To translate Learner #1's moment of "Eureka!":

DNA is to body what blueprint is to building.

A second learner might wonder which aspect of the cell was targeted in the analogy and come to see this exchange as:

DNA is to body what blueprints are to architect.

This is obviously a very confused learner and, because initial learning often is difficult to break, this misconception may become ingrained.

In spite of this inherent issue, the simplicity of this device does allow much participation on the part of learner if the use of analogies is incorporated into the classroom routine.  For example, after introducing new material, an instructor may ask learners to relate the material to something have seen before.  Typical responses begin with "You mean, like in..."  and often conclude with references to a movie, household object, etc.


Itemized analogies

The second category of analogies is generally more structured as well as more complex.  This form actually uses the "A is to B as C is to D" template, although this format is once again abbreviated.  For example, the components of a camera may be related to the anatomy of a human eyeball.  Each item may be listed as:  "lens = cornea, eyelid = lens cap, film = retina," etc.

This is especially useful with large scale constructs such as the organs of the body, cell organelles, parts of an atom, etc.  Although relating human anatomy to cellular anatomy is tempting (and many learners will initiate this line of thinking), I have found that it is better to work from something outside of the discipline under study in order to study something within that discipline.  The rationale for this is that those learners who would have the most difficulty understanding cellular anatomy may not have the most thorough grasp of human anatomy at that point (perhaps if it was recently covered in the same course...).

A better approach, one more grounded in social constructivism, might be to have learners form groups to design factories with an intended product, several levels of security, some form of power, a system of internal communication, etc.  All the while learners working, they have no idea that they are developing half of the analogy to the cell organelles they are about to study.  They will likely remember the components of the factory they created (which can often be quite imaginative and downright hilarious) and these elements can be made reference to throughout the unit.

This style of analogy allows much unrelated information to be connected through an attachment to a known entity.  In memorizing the respective functions of cell organelles, learners can draw from their understanding of a similar complex entity such as a factory.  Their recognition that a factory is surrounded by a fence translates into an understanding that a cell must have something which serves a similar purpose: a membrane.  Similarly, a factory must have a means of distributing its products, therefore a cell must have a structure to serve a similar purpose: the Golgi apparatus.  This item by item comparison is similar to the mnemonic method known as locii in which an individual remembers a sequence of unrelated items by imagining them in various locations within the same physical structure (rooms in a house, for example).  Itemized analogies are a superior method in that the items compared are ideally similar in function as well.


Anecdotal analogies

Humans have natural tendency to latch on to information presented in narrative form.  In his book Data Smog, author David Shenk (1997) coins this trait "anecdotage." He claims that there is something about the way the human psyche is structured that gives a much greater precedence to learning through information organized in a story.

The most involved level of analogistic thinking is probably best demonstrated in developing a situation, process, or short story which describes the material under study.  Whereas similes generally only comment on one item and itemized analogies are best suited for the features of static objects, anecdotal analogies work well in explaining processes or any sort of content which has a sequence of events or steps.

The process of building a protein from the instructions on a strand of DNA is perhaps one of the most fundamental concepts in all of biology.  At the same time is it one of the most complex to teach.  Today there are countless computer animations on video and on the internet which describe what once took much arm waving and bouncing between diagrams.  Still, this is an incomplete way to teach, humanistically speaking.

Converting an already epic story such as DNA transcription/translation into a meaningful, logical sequence of events may seem something of a challenge, but learners often demonstrate considerable aptitude in assigning purposes and personalities to non-sentient molecules.  My biology class this past year resurrected the factory analogy from the unit on cell organelles and attributed idiosyncrasies and Pulitzer prize-worthy motivation to the entities involved in this process.  This engaged a number of the more dramatic learners who proceeded to develop this analogy as far as it could go.

These types of analogies appear to be most appropriate when material is complex and/or dynamic.  For example, when describing the process of evolution a diagram will not suffice for macro examples of a population undergoing genetic change through natural selection.  This concept, by its very nature, is dynamic.  There is no "snapshot" that can isolate the process either verbally or pictorially.  However, telling the story of the "evolution" of a consumer product, an automobile, for example, may serve to illustrate many features inherent in the definition of evolution such as natural selection (consumers select certain cars for their traits) and modification of design (new features on successive models).


VI USE OF ANALOGIES IN THE CLASSROOM

Employing a Constructivist Approach

As has been implied in other sections, analogies may be generated either by learners or instructors.  Instructor-generated analogies may be dead-on accurate in their application, but they may receive blank looks if the instructor has not drawn upon something which permeates the learners' collective experience.
In general, learner-generated analogies are prone to inaccuracies.  However, they are more meaningful for the learners (not merely the one generating the analogy).  To illustrate this, let me describe some of my history in using analogies.

During my first year teaching chemistry I had a very small class of only eight learners.  I found that I could be fair in giving all my learners opportunities to present explanations of concepts.  Roughly half of the time this was done in whole class discussions, the other half (though these modes typically blurred) learners presented analogies to the class as a means of teaching their peers.

Throughout that year I accumulated quite a repetoir of analogies from which I could draw to explain the concepts covered in chemistry.  I felt that this would be useful in bringing my learners to a quick and easy understanding of these concepts in the upcoming year.  However, during this past year I found that the presentation of these analogies served more to stifle learning than to encourage it.  It seems the learner generated analogies are not better because of their content, but because of the act of their creation.  Wong (1993a) echoes this, pointed out that "the analogy functions more as a means ---as opposed to an end--- in the process of understanding" (p.1271).

Wong (1993b) also points out that when learner-generated analogies are used, their approaches tend to be "more interesting, nontrivial, and personally relevant to the learner" (p.377).  Indeed this was the case in this first chemistry class.  Analogies were often drawn from the most esoteric of sources.  One very interesting and surprisingly accurate analogy related one of the two methods by which the concentration of a solution might be increased to the trash compactor scene in Star Wars.  One learner pointed out that the heroes might be viewed as solute (the dissolved particles) and the space of the room as the solvent (the medium in which the solute was dissolved).  As the walls of the compactor closed in, the space in which the heroes were contained decreased.  This is analogous to allowing a container of salt water to dry.  As the water evaporates, the ratio of salt to water increased.

The level of engagement required to generate such an involved analogy is considerable.  One can conclude that, at least in some learners, the aesthetic appeal of generating interesting analogies was one of the driving forces in the learning process.  Indeed, in using analogies Wong (1993b, after Vosniadou & Brewer, 1987) recommends that one "adopt a generative learning perspective: Understanding is viewed as an iterative, constructive process where the purpose of the task is to develop a plausible explanation rather than to find the single correct answer" (p.370).


The Importance of Prior Knowledge

Wong (1993a) points out that an individual's prior knowledge can influence the effectiveness in promoting learning.  He reminds us that a given domain is unlikely to be equally provocative in all analogies for all individuals.  In chemistry for example, my class last year returned to analogies built around a common theme, that being the film Star Wars.  Unfortunately, when a new learner who had (astoundingly) never seen the film entered the class at midyear, much change was required in finding more accessible domains.  Frequently these proved to be domestic objects and/or phenomena that were general enough to be immediately recognizable to all.

The learners in my chemistry class last year had grown accustomed to working from a specific, rather esoteric base in generating their analogies.  In fact, the generation of analogies became as much a target as reaching an understanding o
[text deleted due to file corruption]
built upon a foundation of prior knowledge.  Analogies naturally draw on prior knowledge of a given object or situation in order to bring about understanding of a particular conceptual target.  However, if the source of the analogy is poorly understood, the connections to the target, if any are made at all, will be rife with misconceptions and/or misalignment of associations between the analogy and target.

A problem was unexpectedly encountered when a new learner entered the class at mid-year.  One of the knowledge bases from which the original learners drew was the film Star Wars, which the new learner had never seen.  Analogies form this source served to generate more confusion instead of structuring learning.  Eventually more common areas of knowledge were substituted so that all could be accommodated, but prior to this re-equillibration analogies were as much a hindrance as a help.

However, even where prior knowledge was common to all involved, different learners sometimes arrived at different understandings of how an analogy connected to the target.  In fact Wong (1993a) found that "the use of analogies is highly sensitive and specific to each individual's understanding of the phenomena.  Each participant's unique knowledge base directly influenced the conceptual problems addressed, the analogies generated, and the understanding constructed" (p.1271).  In Wong's study the same analogy sometimes led to different understandings for different participants.

One method to insure that these alternate conceptions are caught before they are committed to memory is to employ social constructivist approaches (i.e. cooperative group learning, etc.).  The cooperative grouping I used last year required learners to voice their understandings as they were generated and to question disjointed pieces of information.  It was frequently observed that learners would question the validity of the features of an analogy supplied by a classmate if those features do not correspond to the learner's understanding of both the analogy and the target concept.

Another problem encountered when using analogies was gender biasing.  Both the learners and I would often draw analogies from spheres of gender-dominated influence.  For example, males (myself included) often used analogies involving the military or sports to illustrate concepts such as molecular motion and chemical reaction.  This bias was often combated through the use of multiple analogies to illustrate the same point.


Multiple Intelligences

Analogies also tap into the multiple intelligences.  Learners may draw analogies from their knowledge of physical objects, dramatic events, mathematical relationships, music, etc.  Though they may originate as text, analogies may be represented artistically in multimedia presentations to hand drawings.  Some analogies (particularly those of the anecdotal variety) are best suited to performance or perhaps as animations.  Lawson (1993) lists the media in which analogies may be delivered to an audience: 1) verbal, 2) diagrammatic, 3) actu
[text deleted due to file corruption]
of air molecules under pressure in a can will typically have the insides of the can made visible, and the air molecules represented many times larger than they would exist in reality.  The molecules themselves are represented as spheres in spite of the fact that roughly 99% of  the atmosphere is composed of diatomic or larger molecules.  The fact that the molecules are in motion is represented by an arrow indicating the probably straight-line direction of motion.  The arrow is a reference (both in name and depiction) to the weapon of the same name, derived no doubt from its ability to travel in a straight line.

Instructors should seek to present analogies in several sensory modes.  Additionally, learners should have the opportunity to demonstrate their understandings of new knowledge through analogies in visual as well as verbal styles.


Analogies as Modes of Assessment

While the majority of the literature discusses analogies in a teaching context, they have a double role in the classroom, both as a tool for teaching as well as demonstrating learning.   Analogies allow for a great variety of assessment questions.  For example, a fill-in-the-blank question might take the form: "car is to gas as cow is to _________."  The use of analogies might also be presented as an option on a written assessment.  Without intending to I presented the opportunity for learners to adopt less traditional modes of explanation in their responses.

Last year on a short answer styled assessment, one enterprising learner explained the concept of secondary cell messaging with a labeled illustration.  Secondary cell messaging involves the passing of a chemical signal to the inside of a cell without making contact with the outside.  This particular learner drew a picture of a guard passing a note from a mother to her son, a prisoner inside of a prison.  The mother was labeled as the primary messenger, the guard as the secondary messenger, the prisoner as the target, and the outside wall of the prison as the cell membrane.  The expression that a picture is worth a thousand words certainly held true here as this response was simultaneously the most succinct and the most thorough of any in the class.


Overextension of Analogies

Researchers have observed that learners occasionally demonstrated a tendency to overextend analogies into realms that were scientifically incorrect (Wong, 1993a).  This is the flip side to working with learner-generated analogies.  Learners typically do not have sufficient knowledge of content to know how far analogies can be extended before they reach the limit of accuracy.

The potential harm of this process lies in the effect of initial learning which could prove difficult to break.  If a particularly interesting comparison was made between the target and the analogy learners may recall this connection in spite of its erroneousness.  In class discussions it was important to establish a signal that overextension was occurring.


VII SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS

Summary

Some general guidelines are presented below for using analogies:


Conclusions

The postmodern philosopher Jacques Derida contends that there is no such thing as an original author.  By this he means that all knowledge is built upon preceding constructions.  In our attempts to anchor new learning to prior understandings, we often rely on representative elements which are reminiscent of other, more familiar entities.

What I have come to conclude through both research of the existing literature on the topic and my experience in the classroom is that analogies are not at all the isolated technique they are represented as in most accounts.  Analogies may take visual or verbal forms as they are inherent properties of both language as well as diagrammatic representations.  Analogies operate within almost any conceivable theoretical framework, and they are a proven method of forming connections among concepts and factual items in learners' understandings.

However, like so many other educational approaches, the use of analogies is not something which can be dropped right into any pedagogical environment.  In order to effectively employ the use of analogies in a classroom.  Wong (1993b) warns that "the use of analogies requires a willingness and ability to conjecture, to see the value of one's own ideas, and to view scientific explanations as tentative and open to change" (p.378).  A classroom which does not already possess these qualities will be crippled in dealing with analogies at the start.  Instructors should view analogies not as a single tool, but as a family of methods for achieving understanding among learners.


Recommendations

Lawson & Lawson (1993) argue that "an active topic for science education research should be the identification of specific analogies for specific scientific concepts and the exploration and evaluation of their limitations and most effective use" (p.1343).  However, the delivery of analogies does not result in the same degree of learning as requiring learners to develop their own analogies.  Further research should reflect this understanding.

Further research is also needed on the dynamics of analogy usage in the classroom (also recommended by Thiele and Treagust, 1994).  The social process of generating and modifying analogies has not been adequately examined.  An understanding of this process is crucial because analogies are vehicles for learning as much as final products.


REFERENCES
Curtis, R. V. (1988).  When a science analogy is like a social studies analogy: A comparison of text analogies across disciplines.  Instructional Science 17, 169-177.

Friedel, A. W., Gabel, D. L., & Samuel, J. (1990).  Using analogies for chemistry problem solving: Does it increase understanding?  School Science and Mathematics 90, 674-682.

Gabel, D. L. & Sherwood, R. D. (1980). Effect of using analogies on chemistry achievement according to Piagetian level.  Science Education 64, 709-716.

Lawson, A. E.  (1993).  The importance of analogy. Journal of Research in Science Teaching 30, 1213-1214.

Lawson, D. I. & Lawson, A. E.  (1993).  Neural principles of memory and a neural theory of analogical insight. Journal of Research in Science Teaching 30, 1327-1348.

Miyake, N. & Norman, D. A. (1979). To ask a question, one must know enough to know what is not known. Journal of Verbal Learning and Verbal Behavior 18, 357-364.

Petrie, H. G. (1979).  Metaphor and learning.  In A. Ortony (Ed.), Metaphor and thought.  London/New York: Cambridge University Press.

Plato, Meno, 8oE; Jowett translation.

Schenk, D. (1997). Data smog: Surviving the information glut.  New York: HarperCollins.

Schon, D. A. (1979).  Generate metaphor: A perspective on problem-setting in social policy.  In A. Ortony (Ed.), Metaphor and thought.  London/New York: Cambridge University Press.

Sutton, C.  (1993).  Figuring Out a Scientific Understanding. Journal of Research in Science Teaching 30, 1215-1227.

Thiele, R. B. & Treagust, D. F. (1994).  An interpretive examination of high school chemistry teachers' analogical explanations. Journal of Research in Science Teaching 31, 227-242.

Vosniadou, S. & Brewer, W. F. (1987).  Theories of knowledge restructuring in development.  Review of Educational Research 57, 51-67.

Wolfe, P. & Brandt, R. (1998).  What Do We Know from Brain Research.  Educational Leadership 56, 3.

Wong, E. D.  (1993).  Understanding the Generative Capacity of Analogies as a Tool for Explanation. Journal of Research in Science Teaching 30, 1259-1272.

Wong, E. D.  (1993).  Self-Generated Analogies as a Tool for Constructing and Evaluating Explanations of Scientific Phenomena. Journal of Research in Science Teaching 30, 367-380.

Webster. (1993).  Merriam-Webster's Collegiate Dictionary.  United States of America: Merriam-Webster, Incorporated.


All contents copyright Alexplorer.
Back to the Articles