227

CHAPTER 1: STATEMENT OF THE PROBLEM

Introduction

Science educators face a formidable assemblage of duties in science education. The National Science Education Standards (1996) report that teachers should help students "…develop the knowledge, understanding, and abilities described in the content standards." (p. 23). However, the knowledge students are to develop are often incongruent with the science knowledge and understanding with which students arrive in science classes. Cobern (1994) suggests that a substantial change in science knowledge requires a fracturing of what is essentially students’ natural understanding of their world. Teachers must first contend with the conceptual frameworks or science conceptions that students have accumulated from their life experiences before they can facilitate the acquisition of scientifically accurate conceptions (Driver, Guesne & Tiberghien, 1985; Driver, Squires, Rushworth & Wood-Robinson, 2001).

In order to guide the development of students' science knowledge and understanding, teachers must be aware of what students already "know". The adage "you have to start from where they are" comes to mind. However once teachers have located the "you are here" sign, on the students' conceptual framework, they are still challenged

1

with planning the best itinerary to help the student reach the desired destination of consensual scientific knowledge. A learner’s conceptual framework is like a skeletal support, or filter of prior knowledge that is used as the basis for sorting and constructing new information. This course of action—how to bridge the content gap between where students are and where we want them to be—would best be charted if we had information on the strategies that students use to progress between their conceptual frameworks.

Problem

Just as the world observes changes in acceptable science theories over time, science educators notice conceptual changes in students' theories about scientific phenomena. (Hewson & Hewson, 1984; Halloun & Hestenes, 1985). Science teachers are challenged with the monumental task of helping students to adjust their pre-formal instruction science conceptions to more closely approximate globally accepted science conceptions (Driver et al., 2001). Sometimes this task can be attained with relative ease when students can annex concepts presented in formal instruction with their existing knowledge. However, this process can also be arduous, as children’s ideas are resistant to change (Carey, 1985; Novak, 1988; Bishop & Anderson, 1990). Changing students’ thinking is a difficult and persistent impediment in science education (Walberg, 1991). This is particularly true when new concepts presented contradict students’ existing knowledge, requiring students to reconstruct their knowledge (Hewson & Hewson, 1984).

In order to fulfill the role of teachers as defined by the National Science Education Standards (1996), teachers must be able to diagnose not only students' conceptualizations but also prescribe subsequent additions or remediation. The difficulty is how to go about performing this task? There has been a move away from the view that students are tabula rasa, or blank slates (Mintzes, 1984; Bransford, Brown & Cocking, 1999) that have knowledge imparted to them by their teachers. Many researchers (von Glasersfeld 1993; Tobin, & Tippins, 1993 ; Mintzes, Wandersee & Novak, 1998; Lorsbach & Tobin, 2000) instead hold students construct and alter their own knowledge. Understanding how students navigate this process should give researchers and practitioners valuable insight on how teachers could effectively aid students in transitioning between their naïve science theories and accepted science theories.

Purpose

Researchers recognize that only the learner can choose to consciously and deliberately reconstruct his or her cognitive framework (Novak, 2002). Researchers also acknowledge that rote learning is insufficient in replacing alternative conceptions (Ausubel, 1968) with consensual science conceptions. The purpose of this study was to observe, document and report on how learners reconstruct their cognitive frameworks and navigate conceptual change from prior knowledge to acceptable knowledge. My research interests were focused on what naturally occurs in the minds of students who acquire scientific conceptions, and the thought processes that students operate to amend their prior knowledge. My practical locus was to gain insight on what strategies, metacognitive or otherwise, students employ to adjust their existing theories so that practitioners can encourage these tactics in their pedagogical approach.

Through this study I investigated how students manipulate their prior knowledge and naïve theories about genetic inheritance, to successfully achieve conceptual change in the science classroom. I attempted to capture the metamorphosis of scientific understanding through student metacognition. I anticipate the results of this study will contribute to the literature on conceptual change and pedagogical strategies to better facilitate conceptual change in science classes. It is my sincere desire to contribute to the research in this field in order to aid teachers, myself included, in facilitating the occurrence of conceptual change in our students.

This study did not focus on motivation’s effect on conceptual change (Pintrich et al., 1993). The qualitative nature of this study should minimize the importance of motivation on conceptual change. Although motivational forces may affect the quantity and perhaps even quality of conceptual change, the basic cognitive processes should remain constant.

Rationale

Along with many of my colleagues in teaching, I have experienced lessons where I have 'taught my heart out' using varied instruction and student engagement to facilitate my students' understanding. My explanations were so lucid and my examples so intelligible that I was confident my students had attained scientific insight and understanding. However, upon assessing my charges, I found that their scientific understanding appeared to be a gallimaufry of concepts, the pieces of which I did not fully recognize.

I consulted my lesson plans to see whether I had furnished them with the alternate conceptions that they had so skillfully assembled. Of course I did not find them there. I then surmised that my students had not been listening attentively, and that was responsible for their failure to learn what I was sure I taught. However upon closer inspection of their notes I found that they had copied everything I had written and said, so they did give me their attention. I wondered if perchance I was a poor communicator, or they had deficits in their abilities of comprehension. However, after investigating each hypothesis, I found no satisfactory explanation. Perhaps it was a combination of all of the above. Surely there was a reason why they did not get it the way I had given it. I accepted this phenomenon as one of the innumerable enigmas of education until I happened upon Piaget's theory of assimilation and accommodation. Assimilation and accommodation refer to how learners incorporate new information into their preexisting cognitive structures or schema. These processes occur concurrently as learners observe and interpret their environment. Assimilation occurs when students incorporate new information into present cognitive frameworks conserving organization whereas accommodation requires modification of cognitive frameworks to accommodate new information (Piaget, 1981).

In assimilation, students transform incoming information to fit their existing ways of thinking. They interpret and distort information according to their own way of thinking. This is akin to adding a sandwich to an already full lunchbox. Without creating space for the sandwich, it is likely that it will get squished or altered in some way. In accommodation, students must adjust their cognitive constructs, which would be like re-arrangement of the contents of your lunchbox so that the sandwich can fit unaltered. This may result in the removal, replacement or reconfiguration of some of the lunchbox contents. Accommodation often results in a conceptual change with the new lunchbox configuration being a new concept that is different or changed from the old one. Conceptual change occurs when a learner modifies their conceptual framework.

After being exposed to Piagetian theories, I believed that the phenomenon that I was observing was congruent with assimilation and accommodation. I hypothesized that while some students were adjusting their conceptual frameworks, others were essentially attaching transformed pieces of new information to their existing theories without reconciling the inconsistencies. This resulted in a collision of ideas that was producing the disorder that I was finding as I assessed students. This interest in how students mediate new knowledge led me to the research questions that I posed in this study.

Research Questions

The initial guiding questions for this study were:

1.  How do students in the process of changing their naïve science theories to accepted science theories describe their journey from prior knowledge to current conception?

2.  What are the methods that students utilize to bridge the gap between alternate and consensual science conceptions to effect conceptual change?

These questions guided the study in the types of data I collected and my methods for data collection and analysis.

In order to ascertain prior knowledge, student prior knowledge was assessed through pre-instruction activities. Knowledge of the science content was then assessed after instruction on the science content. Data collection focused on those students who demonstrated change from their naïve science theories to accepted science theories, as illustrated through gains in content knowledge and concept map development. These students were encouraged to describe their thinking, metacognition, strategies, etc. in explaining how they moved from their prior knowledge to their final conceptions.

My research questions were taken from a realistic perspective instead of an instrumentalist perspective (Maxwell, 1998). In dealing with patterns that are not directly observable—such as thought processes—it is important to allow students to report on what they were thinking and feeling during the period of conceptual change. I inferred my analysis from students’ observations. I used member checks, allowing students to review interview transcripts in order to verify my description of what happened in their minds.

High school biology students were observed and interviewed before, during and after a unit of study in genetics. Through a semi-structured interview I investigated students’ knowledge of genetics prior to formal instruction in their biology course. I used interviews, student artifacts and focus groups, to sketch the evolution of students' knowledge. After students received formal instruction and assessment on genetics and inheritance, I presented them with the artifacts that they produced and ask them to reflect on their experiences, relating what processes occurred during their cognitive transformation. The answer to my first research question was primarily descriptive, illustrating what processes, metacognitive and or otherwise, occurred in students who had the greatest amount of conceptual change as indicated by their post-test scores.

The data collected from my first research question, along with student accounts of when, why and how their ideas changed should provide insight on how students reconstructed their concepts to model acceptable scientific concepts. The second research question gathered data on which techniques facilitated a paradigm shift to result in conceptual change. My assumptions included the following:

1. Students were motivated and able to learn

2. Students possessed prior knowledge in context, even if not in content (Osman & Hannafin, 1994)

3. Students in some way accessed prior knowledge in order to change and create new knowledge

4. Students used metacognitive strategies in negotiating new knowledge

5. Students constructed, deconstructed and reconstructed their own knowledge

6. Students were presented with intelligible, plausible and fruitful new conceptions (Posner, Strike, Hewson & Gertzog, 1982; Hewson 1982)

7. Students changed their concepts of genetic inheritance after instruction on genetics

Theoretical Framework

Conceptual change has become a central theme and organizing concept in science education research (Thorley & Stofflett, 1996) as well as a science curriculum emphasis (Blosser, & Helgeson, 1990). The idea of conceptual change arose in science education, as an analogy derived from the history and philosophy of science that helped to explain the difficulties people experience in changing from one explanatory model to another (Hewson, 1992). Conceptual change occurs when learners alter their thinking or theoretical frameworks about something. The conceptual change model, or CCM as outlined by Posner, Strike, Hewson & Gertzog (1982) offers four cognitive conditions that must be met in the students’ mind order for conceptual change to occur:

  1. Dissatisfaction with a students’ existing conceptions
  2. New conceptions must be intelligible or easily understood
  3. New conceptions must be plausible; believable and adequately explaining problems encountered by the student
  4. New conceptions must be fruitful; useful possibilities to explain new situations

Contemporary ideas in the philosophy of science propose two discernible phases of conceptual change in the scientific community. The first phase involves a definition of the problem to be solved, strategies for solving it and the formation of standards determining acceptable solutions. The second phase of conceptual change occurs when these original tenets require modification (Posner et al., 1982). Halloun & Hestenes (1985) believe learning processes in individuals to be similar in conceptual changes to scientific knowledge, and that scientific struggles of the past should offer valuable insight into the conceptual difficulties encountered by students. Students organize information into a knowledge base and tend to incorporate new information according to the cognitive structures that they have already constructed. This process is termed assimilation. However, if new information is inconsistent with a student’s naïve theory, then the mental structure must be changed in order to incorporate new information. This reorganization of central concepts is termed accommodation (Piaget & Inhelder, 1969; Posner et al., 1982). Both assimilation and accommodation reflect a constructivist referent, where learners empirically build their own knowledge according to their experiences. Strike and Posner (1992) emphasized that their theory of conceptual change enumerated conditions necessary for conceptual change and is not a prescription for instruction.

When viewed through a constructivist referent, student perspectives move to the forefront of understanding how conceptual change occurs. Constructivism holds that learners build their own knowledge based on their own experiences. If knowledge is personally constructed and negotiated by learners and groups of learners (Vygotsky 1978), it is vital to understand learners’ viewpoints on how they construct and reconstruct their schema. As a result, recent reform efforts within science education focus on the need for students to cultivate conceptual understandings of science rather than rote memorization of science facts (AAAS, 1993, NRC, 1996). Constructivism supports these goals as a viable framework for viewing how learners acquire knowledge.