Naïve Meanings of Force: Coherence vs. Fragmentation

This paper contributes to the literature on conceptual change by engaging in direct empirical comparison of contrasting views. We take up the question of whether naïve physics ideas are coherent or fragmented, building specifically on recent work supporting claims of coherence by Ioannides and Vosniadou (2002). A partial replication of the Ioannides and Vosniadou study resulted in radically different results. We analyze several possible reasons for the differences in our results, but find that none can plausibly account for the differences in our data. We argue that the results of our study undermine claims for coherence in naïve conceptualizations of force. Conceptual Change Research: The State of the Art Since the constructivist revolution, there has been a fairly wide agreement that the phenomenon of naïve or intuitive conceptions in the learning of science deserves consideration. The phenomenon of naïve ideas strongly suggests that a conceptual change approach should be helpful in understanding those ideas and their trajectories during instruction. However, beyond a superficial agreement that conceptual change is an important phenomenon to understand, a huge diversity of points of view remains concerning the processes of conceptual change. Among the fault lines in conceptual change research, one of the most contentious and probably most consequential concerns the nature of uninstructed knowledge relevant to learning particular domains, such as physics. On the one hand, some researchers contend naïve knowledge is coherent, even theory-like. For example, students may have “the impetus theory” (McCloskey, 1983), or they have one of a few models of the earth consistent with a coherent “framework theory” (Vosniadou and Brewer, 1994). On the other hand, some researchers (diSessa, 1988; Minstrell and Stimpson, 1992) argue that naïve ideas are many, diverse, and not theoretical in any strong sense of the word. In this paper, our reference theoretical frame is the Knowledge in Pieces view espoused by diSessa (1988). In this view, naïve knowledge consists significantly (but not exclusively) of hundreds or thousands of intuitive elements, which are activated in specific contexts and, as a whole, exhibit some broad systematicity, but are not systematic enough to be productively described as “a theory” or any similar term. Aside from the intractability of deep theoretical differences, the study of conceptual change has been limited by the fact that researchers have been somewhat “spread thin,” looking at a wide range of domains and issues (e.g., the shape of the earth, the effects of forces, the meaning of “alive,” the distinction between heat and temperature) and a wide range of ages, from pre-school to university students. In addition, the methodologies of various researchers have involved data collection as diverse as clinical interviews, performance on physical or computer-implemented setups, and answers to paper-and-pencil questions. For the lack of common ground, it is possible different results are more the result of asking different questions, in different ways, of different subjects. This research aims to respond to the diversity of theoretical frames and contentions about conceptual change in three ways. First, we aim to find common empirical grounds with other researchers, both in terms of age level of subjects and in terms of conceptual focus. Furthermore, we deliberately seek to minimize differences in methods. Finally, we aim to engage specific other theoretical frames and their empirical results, rather than pursuing only paths of investigation natural only to our own theoretical and empirical tradition. In this work, we capitalize on recent study conducted by Ioannides and Vosniadou (2002), which claims that a framework theory guides and constrains the meaning children give to the word “force.” Ioannides and Vosniadou (“I&V” for brevity) further claim that instruction destabilizes students’ ideas, which results in increasing fragmentation of knowledge as students develop. This hypothesis of increasing fragmentation accommodates data and analysis from the Knowledge in Pieces perspective that show fragmentation and contextual dependency in older students’ (high school and university) reasoning. I&V’s study is fortuitous for our purposes for several reasons. First, it covers some of the same ideas—namely force and motion—that have been the staple of Knowledge in Pieces research. Second I&V’s work stems from and apparently corroborates a strong theoretical position on conceptual change favoring coherence and limited diversity