Science Learning

EXPLANATION AND ARGUMENTATION
Deanna Kuhn
David Dean Jr.

KNOWLEDGE ORGANIZATION AND UNDERSTANDING
Andrea A. diSessa

STANDARDS
Angelo Collins

TOOLS
Michele Spitulnik
Marcia Linn

EXPLANATION AND ARGUMENTATION

The K–12 U.S. science education standards, now published state by state, without exception cite competence in scientific investigation as an important curriculum goal from the early grades on. Students, it is claimed, should be able to formulate a question, design an investigation, analyze data, and draw conclusions. Reference to such skills in fact appears in discussions of curriculum objectives extending well beyond the discipline of science. The following description, for example, comes not from science education literature but from a description of language arts goals specified by the National Council of Teachers of English (NCTE): "Students conduct research on issues and interests by generating ideas and questions, and by posing problems. They gather, evaluate, and synthesize data from a variety of sources … to communicate their discoveries in ways that suit their purpose and audience" (NCTE and International Reading Association website).

It is important that the cognitive skills involved in such activities be defined in a clear and rigorous enough way to make it possible to specify how they develop and how this development is best supported educationally. At the same time, to make the case that scientific thinking is a critical educational objective, it must be defined more broadly than "what professional scientists do." Scientific thinking is essential to science but not specific to it.

But are not children naturally inquisitive, it may be asked, observant and sensitive to the intricacies of the world around them and eager to discover more? Do inquiry skills really need to be developed? The image of the inquisitive preschool child, eager and energetic in her exploration of a world full of surprises, is a compelling one. But the image fades as the child grows older, most often becoming unrecognizable by middle childhood and certainly by adolescence. What happens to the "natural" inquisitiveness of early childhood? The answer is that it needs to be channeled into the development of the cognitive skills that make for effective inquiry. More needs to be done than keeping alive a "natural curiosity." The natural curiosity that infants and children show about the world around them needs to be enriched and directed by the tools of scientific thought.

Coordination of Theories and Evidence

One way to conceptualize these scientific thinking skills is as skills in the coordination of theories and evidence. Even very young children construct theories to help them make sense of the world, and they revise these theories in the face of new evidence. But they do so without awareness. Scientific thinking, in contrast, involves the intentional coordination of theories with new evidence. Another way to define scientific thinking, then, is as intentional knowledge seeking. Scientific thinkers intentionally seek evidence that will bear on their theories. Defined in this way, the developmental origins of scientific thinking lie in awareness of knowledge states as generating from human minds. Awareness of the possibility of false belief is thus a prerequisite to scientific thinking. If knowledge states are fallible, one's own knowledge may warrant revision in the face of new evidence.

Regarded in this way, scientific thinking is more closely aligned with argument than with experiment and needs to be distinguished from scientific under-standing (of any particular content). Scientific thinking is something one does, whereas scientific understanding is something one has. When conditions are favorable, the process of scientific thinking may lead to scientific understanding as its product. Indeed, it is the desire for scientific understanding–for explanation–that drives the process of scientific thinking. Enhanced understandings of scientific phenomena are certainly a goal of science education. But it is the capacity to advance these understandings that is reflected in scientific thinking.

Scientific thinking requires that evidence be represented in its own right, distinct from the theory, and that the implications of the evidence for the theory be contemplated. Although older children, adolescents, and even adults continue to have trouble in this respect, young children are especially insensitive to the distinction between theory and evidence when they are asked to justify simple knowledge claims.

Note that the outcome of the theory-evidence coordination process remains open. It is not necessary that the theory be revised in light of the evidence, nor certainly that theory be ignored in favor of evidence, which is a misunderstanding of what is meant by theory-evidence coordination. The criterion is only that the evidence be represented in its own right and its implications for the theory contemplated. Skilled scientific thinking always entails the coordination of theories and evidence, but coordination cannot occur unless the two are encoded and represented as distinguishable entities.

The following six criteria for genuine scientific thinking as a process (in contrast to scientific understanding as a knowledge state) can be stipulated:

1. One's existing understanding (theory) is represented as an object of cognition.
2. An intention exists to examine and potentially advance this understanding.
3. The theory's possible falsehood and susceptibility to revision is recognized.
4. Evidence as a source of potential support (or nonsupport) for a theory is recognized.
5. Evidence is encoded and represented distinct from the theory.
6. Implications of the evidence for the theory are identified (relations between the two are constructed).

The Epistemology of Scientific Learning

There is more to scientific thinking that needs to develop, however, than a set of procedures or strategies for coordinating theories with evidence. As hinted earlier, at its core this development is epistemological in nature, having to do with how one understands the nature of knowledge and knowing. An until recently largely neglected literature on the development of epistemological understanding shows a progression from an absolutist belief in knowledge as certain and disagreements resolvable by recourse to fact, to the multiplist's equation of knowledge with subjective opinion. Only at a final, evaluativist level is uncertainty acknowledged without foregoing the potential for evaluation of claims in a framework of alternatives and evidence.

If facts can be readily ascertained with certainty, as the absolutist understands, or if all claims are equally valid, as the multiplist understands, scientific inquiry has little purpose. There is little incentive to expend the intellectual effort it entails. Epistemological understanding thus informs intellectual values and hence influences the meta-level disposition (as opposed to the competence) to engage in scientific thinking.

Similarly, a strategic meta-level that manages strategy selection can be proposed. This metastrategic level entails explicit awareness of not so much what to do as why to do it–the understanding of why one strategy is the most effective strategy to achieve one's goals and why others are inferior. It is this meta-strategic understanding that governs whether an appropriate inquiry or inference strategy is actually applied when the occasion calls for it.

The phases of scientific thinking themselves–inquiry, analysis, inference, and argument–require that the process of theory-evidence coordination become explicit and intentional, in contrast to the implicit theory revision that occurs without awareness as young children's understandings come into contact with new evidence. Despite its popularity in educational circles, once one looks below the surface of inquiry learning, it is less than obvious what cognitive processes are entailed. Research suggests that children lack a mental model of multivariable causality that most inquiry learning assumes. They are not consistent over time in their causal attributions, attributing an outcome first to one factor and later to another, and infrequently do they see two factors as combining additively (much less interactively) to produce an outcome. A mature mental model of causality in which effects combine additively to produce an outcome is critical to adoption of the task goal of identifying effects of individual factors and to the use of the controlled comparison strategy (which has been the focus of research on scientific reasoning) to achieve that goal. If a single (not necessarily consistent) factor is responsible for any outcome (as reflected in the inferential reasoning of many young adolescents), what need is there to worry about controlling for the effects of other factors?

If it is this total structure (including meta-strategic, meta-cognitive, and epistemological understanding, as well as values) that needs to develop, where do educators start? They probably need to begin at multiple entry points. Opportunities should be plentiful for the frequent and regular exercise of skills of inquiry, analysis, inference, and argument, thereby enabling these skills to be practiced, elaborated, consolidated, and perfected. At the same time, meta-level awareness and understanding of skills should be promoted by helping students to reflect on what and particularly how they know and what they are doing as they acquire new knowledge. The two endeavors reinforce one another: understanding informs practice and practice enhances understanding.

The Social Context

Equally critical is the social context in which all of this needs to take place, the often neglected dispositional side of knowing. Educators want children to become skilled scientific thinkers because they believe that these skills will equip them for productive adult lives. But it is not enough that these adults believe it. If children are to invest the sustained effort that is required to develop and practice intellectual skills, they too must believe that learning and knowing are worthwhile. These values and beliefs can develop only through sustained participation in what Ann Brown in 1997 called a "community of learners." Here, scientific thinking skills stand the best chance of developing because they are needed and practiced and socially valued.

Returning scientific thinking to its real-life social context is one approach to strengthening the meta-level components of scientific thinking. When students find themselves having to justify claims and strategies to one another, normally implicit meta-level cognitive processes become externalized, making them more available. Social scaffolding (supporting), then, may assist less able collaborators to monitor and manage strategic operations in a way that they cannot yet do alone. A number of authors have addressed scientific thinking as a form of discourse. This is of course the richest and most authentic context in which to examine scientific thinking, as long as the mistake is not made of regarding these discourse forms as exclusive to science. Scientific discourse asks, most importantly, "How do you know?" or "What is the support for your statement?" When children participate in discourse that poses these questions, they acquire the skills and values that lead them to pose the same questions to themselves. Although central to science, this critical development extends far beyond the borders of traditional scientific disciplines.