- Top of page
- 1. Methods
- 2. Results
- 3. Discussion
- Supporting Information
A central tenet of constructivist models of conceptual development is that children's initial conceptual level constrains how they make sense of new evidence and thus whether exposure to evidence will prompt conceptual change. Yet little experimental evidence directly examines this claim for the case of sustained, fundamental conceptual achievements. The present study combined scaling and experimental microgenetic methods to examine the processes underlying conceptual change in the context of an important conceptual achievement of early childhood—the development of a representational theory of mind. Results from 47 children (M age = 3.7 years) indicate that only children who were conceptually close to understanding false belief at the beginning of the study, and who were experimentally exposed to evidence of people acting on false beliefs, reliably developed representational theories of minds. Combined scaling and microgenetic data revealed how prior conceptual level interacts with experience, thereby providing critical experimental evidence for how conceptual change results from the interplay between conceptions and evidence.
In developing evolutionary theory, a critical step in Darwin's thinking came when the numerous species and subspecies of mockingbirds on the Galapagos Islands led him to realize that the idea of “fixity of species”—that species are fixed and stable over time—was wrong. Darwin's insights proceeded in a progression of ideas that unfolded over years, but recognizing within-species change laid the groundwork for the major conceptual breakthroughs that came next—the ideas that new species can evolve and that the mechanisms that drive within-species change and the origins of new species operate on population-level variation—and thus the paradigm-shift that revolutionized modern biology. A process whereby preliminary conceptual insights lay the groundwork for paradigm changes is seen throughout the history of science (Kuhn, 1962).
Potentially, a similar process might drive conceptual change in cognitive development. According to both traditional (Piaget & Inhelder, 1969) and modern constructivist (Xu, 2007) theories, children's initial conceptual framework constrains how they make sense of new evidence. For Piaget, children attempt to interpret new evidence within their current conceptual framework (assimilation), making small modifications to cope with inconsistent data (accommodation), until they are prepared to adopt a new conceptual framework (equilibration). In this view, it is not advances in child language or mental age that are crucial for conceptual change, but the attainment of earlier conceptual insights that provide the groundwork for making sense of new evidence.
Similarly, from the perspective of current rational models (Tenenbaum, Kemp, Griffiths, & Goodman, 2011; Xu, 2007), learning involves the integration of new data with children's prior beliefs (constrained by a hypothesis space), with the product being both the gradual updating of these prior beliefs—which then influence the interpretation of new data—and when necessary, a revision of the underlying hypothesis space (Gopnik et al., 2004). Consistent with this perspective, children's prior beliefs constrain how they learn from new statistical evidence (Schulz, Goodman, Tenenbaum, & Jenkins, 2008; Sobel, Tenenbaum, & Gopnik, 2004; Teglas, 2011; Xu & Tenenbaum, 2007). For example, children learned new causal relationships from statistical evidence more easily when the evidence was consistent with their prior beliefs about the principles that underlie physical causality (e.g., when the causes were spatially contiguous to the effects rather than acting at a distance; Kushnir & Gopnik, 2007). As another example, 3-year-olds infer causal relations from statistical evidence more quickly when the causal relations are consistent with their domain-specific naïve theories (e.g., they more easily learned biological causes for biological effects than psychological causes for biological effects; Schulz, Bonawitz, & Griffiths, 2007; see also, Sobel & Munro, 2009). Furthermore, developmental changes in children's naïve theories of human action influence how 4- and 6-year-olds use patterns of statistical co-variation to explain behavior (Seiver, Gopnik, & Goodman, in press). Even when statistical evidence is inconsistent with children's prior beliefs, however, preschool-age children are able to rationally update their beliefs if they are given multiple training sessions over time (Bonawitz, Fisher, & Schulz, in press). Children's prior beliefs also constrain how they explore and understand new evidence in exploratory-play and question-asking tasks (Bonawitz, van Schijndel, Friel, & Schulz, 2012; Legare, 2012). More generally, the importance of assessing children's initial beliefs about phenomena has been a common theme throughout the educational and developmental literatures (Vosniadou & Brewer, 1992).
Yet there has been surprisingly little experimental research examining these processes as they unfold over time, as opposed to within one or two experimental sessions (for an exception, see Bonawitz et al., 2012, where children participated in four sessions over the course of 2 weeks), or with respect to fundamental conceptual changes that are more akin to the paradigm changes in science described above. With respect to examining fundamental conceptual change over time, many cross-sectional studies have found that beliefs change as children get older, but almost none have both examined the effects of new evidence experimentally and assessed progressions of conceptual change. Here, we examine these processes in the context of a fundamental conceptual change that occurs in early childhood—the development of a representational theory of mind.
Transition to a representational theory of mind, typically measured via a transition from consistently failing to consistently passing explicit false belief (FB) tasks, provides an excellent opportunity to test models of conceptual change for several reasons. First, the developmental trajectory of this conceptual change in the preschool years is well established (for meta-analysis, see Wellman, Cross, & Watson, 2001). Second, although children show some implicit understanding of FB in infancy (Onishi & Baillargeon, 2005; Scott & Baillargeon, 2009; Scott, Baillargeon, Song, & Leslie, 2010; Song & Baillargeon, 2008; Song, Onishi, Baillargeon, & Fisher, 2008; Surian, Caldi, & Sperber, 2007), the development of an explicit representational theory of mind in preschool remains an important conceptual achievement. Indeed, the gap between infants' implicit understanding of FB and the later development of explicit FB concepts makes the development of theory of mind a particularly intriguing developmental puzzle and highlights the importance of understanding the processes that underlie conceptual development in this domain.
Third, preschool theory of mind developments, as indexed by FB developments, qualitatively change how children interact with their environment—much like the paradigm changes discussed above. The central importance of the development of explicit FB concepts in early childhood is underscored by its real-world implications; the ability to pass explicit FB tasks in preschool is correlated with children's popularity with peers (Peterson & Siegal, 2002; Slaughter, Dennis, & Pritchard, 2002), teacher-rated social competence (Astington, 2003; Peterson, Slaughter, & Paynter, 2007; Watson, Nixon, Wilson, & Capage, 1999), and skilled interactions with peers (Dunn, Cutting, & Demetriou, 2000), including abilities to play games like hide and seek (Peskin & Ardino, 2003) and social pretend play (Astington & Jenkins, 1995).
Fourth, the preschool change from consistently incorrect FB judgments to consistently correct ones takes a year or more to accomplish in typically developing children (Wellman et al., 2001). It thus constitutes not only an important change but also a developmentally difficult one that generally requires sustained conceptual development.
Finally, and most important here, the series of conceptual insights that precede the development of FB understanding can be measured via a theory of mind scale (Wellman & Liu, 2004). This scale assesses understanding of (a) Diverse Desires (people can have different desires); (b) Diverse Beliefs (people can have different beliefs); (c) Knowledge-Access (a person will not have knowledge if he or she has not had access to the relevant information); (d) FB (someone can believe something that is false); and (v) Hidden Emotion (someone can feel one way but display a different emotion). In cross-sectional studies, typically developing children reliably proceed in order through this series of understandings (Peterson, Wellman, & Liu, 2005; Wellman & Liu, 2004) and change from one step to the next requires 3–6 months to achieve. In this study, we experimentally examine the role of these preliminary insights in the process of conceptual change to a representational theory of mind.
Although the transition from reliably incorrect to reliably correct FB performance generally takes approximately 1 year, prior research has developed several interventions that facilitate and speed up the development of FB understanding in preschool-age children (Amsterlaw & Wellman, 2006; Lohmann & Tomasello, 2003). Crucially, however, these intervention studies also reveal substantial individual variation in improvement—some children reliably passed FB at posttest, some showed moderate improvement, and some continued to fail. For example, Lohmann and Tomasello (2003) compared several training conditions with young preschoolers, all of whom failed FB at pretest. In the most successful condition, average performance on three FB tasks substantially improved after training; however, even at posttest, individual children's scores ranged from 0 to 3 (similar variation was reported by Amsterlaw & Wellman, 2006). Why do some children develop an understanding of FB following such interventions while others, exposed to the same evidence, do not? This question is fundamental to any theoretical account of the nature of cognitive change.
The possibility that we examine is that children's learning in such interventions is constrained by their previous level of conceptual understanding. That is, that children who are conceptually closer to developing an understanding of FB (i.e., as indicated by their position along the theory of mind scale) will have the prior knowledge that will enable them to make sense of the new evidence presented to them during the study, and thus that this new evidence will prompt conceptual change for these children. In contrast, children who are initially farther away from developing an understanding of FB will not have the requisite prior knowledge to make sense of the new evidence. In this way, we test whether prior knowledge both constrains and enables children's ability to learn from new evidence, in the context of a fundamental, sustained conceptual achievement of early childhood. To test these hypotheses, we recruited a group of children who had not yet developed an understanding of FB, but who varied from one another on the extent to which they had developed prior conceptual understandings. Using the theory of mind scale as our context, we predicted that those who already understood Knowledge Access (KA)—the level that reliably precedes FB understanding in scaling research—would develop an understanding of FB over the course of an extended training period, whereas those who had not yet developed an understanding of KA—but were exposed to the same training sessions—would not. These predictions and the present research help address the fundamental theoretical question of how to characterize cognitive change; in our case, change to a representational theory of mind.
Our methods combined scaling methods with a microgenetic training study. Microgenetic methods rest on fine-grained analyses of cognitive change over multiple successive sessions to provide a rich picture of development and learning as it unfolds (Siegler, 2006; Siegler & Crowley, 1992). Although microgenetic methods have most often been used to examine skill or strategy acquisition (e.g., Luwel, Siegler, & Verschaffel, 2008; Siegler & Chen, 1998; Siegler & Stern, 1998; Siegler & Svetina, 2006), they can also be fruitfully applied to conceptual development (e.g., Opfer & Siegler, 2004, 2007). Our microgenetic methods were inspired by Amsterlaw and Wellman (2006), but critically, we combined this approach with an assessment of children's initial position along the progression of conceptual insights captured by the theory of mind scale. We included sufficient children to model variation in children's progress and attainment of FB understanding. Our microgenetic method differs from a focused training study (e.g., Lohmann & Tomasello, 2003), in that children receive no explicit teaching about FB concepts. Instead, children see people acting in accordance with FBs (evidence that is inconsistent with a non-representational theory of mind), and we assess whether and how this evidence prompts the development of a representational theory of mind.
- Top of page
- 1. Methods
- 2. Results
- 3. Discussion
- Supporting Information
Children's initial conceptual level determined whether and how new evidence provoked conceptual change. Specifically, understanding KA (or not) substantially predicted whether microgenetic exposure to relevant evidence provoked transition to an understanding of FB. Initial conceptual level and the passage of time alone did not provoke this change, as control children who initially understood KA did not develop an understanding of FB. Exposure to evidence alone was also not sufficient, as experimental children who did not initially understand KA also did not develop an understanding of FB. Age was associated with improved understanding of FB, but conceptual change was predicted by the interaction between initial understanding of KA and experimental exposure to relevant evidence, controlling for age.
These data go beyond other studies that have examined the influence of children's prior beliefs on conceptual learning, by examining learning processes as they unfold over time (12 sessions over 6 weeks, as opposed to within a single experimental session). Also, we examined conceptual development with respect to a fundamental conceptual change that prior research has established as an extended and difficult developmental accomplishment; namely, preschool transition to a representational theory of mind. Moreover, we tracked not only children's increased accuracy on FB alone, but their progression along a reliable sequence of preschool theory of mind understandings.
The present data are consistent with the proposal that the development of ToM involves a series of domain-specific conceptual changes. Although these findings do not preclude the possibility that factors external to a conceptual domain—such as children's general processing skills, engagement, inhibitory control, or memory—importantly contribute to conceptual change, the present data suggest that these abilities do not fully account for theory of mind development for several reasons. First, if the Experimental condition supported the development of FB understanding by facilitating these general abilities, it is unclear why it would do so only for children who had previously developed an understanding of KA. Yet children's initial conceptual understanding demonstratively enabled and constrained their potential to learn from new evidence. That is, given the same extended microgenetic experiences, children's prior understandings both enabled learning (for children closer to FB on the theory of mind scale at pretest) and constrained it (for those further away to begin with). Second, we found that our measure of verbal fluency did not predict whether children in the Experimental condition developed an understanding of FB. In future work, it would be useful to include more extensive measures of executive functioning and memory to examine more fully the contribution of these factors in shaping children's conceptual development in this context.
It is worth considering why prior understanding of KA, in particular, enabled progress to FB understanding in our study. We speculate that understanding the relationship between perceptual access and resulting mental states, early acquired in the case of understanding KA, enables recognition of the role of perceptual evidence in belief formation as well (and this also explains why KA reliably precedes FB understanding in cross-sectional and longitudinal theory of mind scaling research, e.g., Wellman, Fang, & Peterson, 2011). Neither understanding Diverse Desires nor Diverse Beliefs requires appreciation of how mental states depend on perceptual experience. Others have speculated on the formative role of understanding perceptual access as a conceptual “prior” for understanding FB evidence (see Gopnik & Wellman, 1994). Our data underwrite further research to address this specific hypothesis.
The current data provide clear support for a basic, but often unexamined, premise of constructivist models of cognitive development—that conceptual development involves the successful building of new insights through an active process of evidence interpretation, consistent with current rational models (Goodman et al., 2006; Ullman, Goodman, & Tenenbaum, 2010). Our data clearly manifest two empirical signatures of such a process of conceptual development: (a) that prior conceptual knowledge influences whether exposure to new evidence results in conceptual change and (b) that learning proceeds in orderly conceptual progressions. Our data evidence these features in extended, sustained childhood learning of demonstrably difficult, everyday concepts. Thus, these data also illustrate the usefulness of combining scaling and microgenetic methods to empirically capture processes of conceptual change.