Children’s causal inferences from indirect evidence: Backwards blocking and Bayesian reasoning in preschoolers

Previous research suggests that children can infer causal relations from patterns of events. However, what appear to be cases of causal inference may simply reduce to children recognizing relevant associations among events, and responding based on those associations. To examine this claim, in Experiments 1 and 2, children were introduced to a “blicket detector,” a machine that lit up and played music when certain objects were placed upon it. Children observed patterns of contingency between objects and the machine’s activation that required them to use indirect evidence to make causal inferences. Critically, associative models either made no predictions, or made incorrect predictions about these inferences. In general, children were able to make these inferences, but some developmental differences between 3- and 4-year-olds were found. We suggest that children’s causal inferences are not based on recognizing associations, but rather that children develop a mechanism for Bayesian structure learning. Experiment 3 explicitly tests a prediction of this account. Children were asked to make an inference about ambiguous data based on the base rate of certain events occurring. Four-year-olds, but not 3-year-olds were able to make this inference.     

Enabling conditions and children’s understanding of pretense

Two experiments examined whether preschoolers’ difficulties on tasks that required relating pretending and knowledge (e.g., Lillard, A. S. (1993a). Young children’s conceptualization of pretense: Action or mental representational state? Child Development, 64, 372-386) were due to children’s inability to appreciate the causal mechanism behind enabling conditions. In Experiment 1, 4-year-olds were told about a character who knew about one kind of animal and did not know about another. The character acted in a manner consistent with both animals. Children were asked whether the character was pretending to be the animal of which he was ignorant. The character’s knowledge was either represented in a generic manner (as a picture) or in a manner that suggested a particular enabling condition relation that children found accessible (as a battery, which most 4-year-olds recognize is critical for making toys work). Children were more successful at relating knowledge and pretending in the battery condition. This improvement in performance extended to another task in which children had to identify the enabling condition relation between knowledge and identification, in which there were reduced demands on the inhibitory mechanisms necessary for success. Experiment 2 found that the results in Experiment 1 were not due to demands of the procedure used in Experiment 1. These results are discussed in the context of recent theories of theory of mind that focus on the importance of causal relations among mental states.     

Just do it? Investigating the gap between prediction and action in toddlers’ causal inferences

Adults’ causal representations integrate information about predictive relations and the possibility of effective intervention; if one event reliably predicts another, adults can represent the possibility that acting to bring about the first event might generate the second. Here we show that although toddlers (mean age: 24 months) readily learn predictive relationships between physically connected events, they do not spontaneously initiate one event to try to generate the second (although older children, mean age: 47 months, do; Experiments 1 and 2). Toddlers succeed only when the events are initiated by a dispositional agent (Experiment 3), when the events involve direct contact between objects (Experiment 4), or when the events are described using causal language (Experiment 5). This suggests that causal language may help children extend their initial causal representations beyond agent-initiated and direct contact events.     

What's new? Children prefer novelty in referent selection

Determining the referent of a novel name is a critical task for young language learners. The majority of studies on children’s referent selection focus on manipulating the sources of information (linguistic, contextual and pragmatic) that children can use to solve the referent mapping problem. Here, we take a step back and explore how children’s endogenous biases towards novelty and their own familiarity with novel objects influence their performance in such a task. We familiarized 2-year-old children with previously novel objects. Then, on novel name referent selection trials children were asked to select the referent from three novel objects: two previously seen and one completely novel object. Children demonstrated a clear bias to select the most novel object. A second experiment controls for pragmatic responding and replicates this finding. We conclude, therefore, that children’s referent selection is biased by previous exposure and children’s endogenous bias to novelty.     

Priming as a way of understanding children’s mental representations of the social world

Priming is a well established tool for experimental examination of how mental representations drive thoughts, feelings, and behaviors that has been widely used in adult research. Priming is also a well established technique in cognitive development research. Social development research, however, has rarely used priming as a research method despite evidence that this technique is promising for helping researchers untangle causal connections between children’s mental representations and children’s social development outcomes. This paper discusses how priming methods may yield important insights into the role that children’s mental representations of the social world play in children’s social functioning. We begin by discussing the theoretical conceptualization underlying priming and priming methods. We next review evidence demonstrating the effectiveness of priming techniques in child development research. We conclude by suggesting ways in which priming can inform future research in social development using research examining attachment, social-information-processing, gender development, and mood and mental health as examples.     

Children's beliefs about instances of mechanical and electrical causation

Two main questions were asked regarding young children's beliefs about causal mediation: What sorts of beliefs about causal mediation are reflected by children's incomplete explanations of causal situations? In particular, do children hold a false belief in action at a distance or do they realize that something must mediate between cause and effect? When presented with a non-visible connection between cause and effect (Experiment I), the children's incomplete (Piagetion Stage 1) explanations either reflected the correct expectation of a mediating connection or else merely reflected identification of the causal agent and no concern one way or another with the issue of causal mediation. This was also the case when the mediating connection was visible and present at the outset (Experiment II). In neither experiment (both of which involved mechanical causation) was there evidence of a false belief in action at a distance. A third experiment involved instances of electrical causation in order to maximize the chances of tapping a false belief. The rationale was that, in their everyday lives, although children do have first-hand experience with the mediating connection in instances of mechanical causation, they do not have such experience with instances of electrical causation. The results from the third experiment were analogous to the results in the other two. It was concluded that, with respect to instances of physical causality, young children do not hold a false belief (in action at a distance) that is later relinquished. Rather, their concerns are, at first, restricted to identifying the causal agent and do not include any beliefs, true or false, about the issue of causal mediation. When they eventually do deal with the question of causal mediation, children hold approximately correct beliefs. In terms of school situations, these findings suggest a shift from providing the child with disconfirming data that will aid him in relinquishing his false beliefs to providing him, instead, with additional data that will supplement his existing, approximately correct beliefs.     

Folkbiology meets microbiology: a study of conceptual and behavioral change

Health education can offer a valuable window onto conceptual and behavioral change. In Study 1, we mapped out 3rd-grade Chinese children’s beliefs about causes of colds and flu and ways they can be prevented. We also explored older adults’ beliefs as a possible source of the children’s ideas. In Study 2, we gave 3rd- and 4th-grade Chinese children either a conventional cold/flu education program or an experimental “Think Biology” program that focused on a biological causal mechanism for cold/flu transmission. The “Think Biology” program led children to reason about cold/flu causation and prevention more scientifically than the conventional program, and their reasoning abilities dovetailed with their mastery of the causal mechanism. Study 3, a modified replication of Study 2, found useful behavioral change as well as conceptual change among children who received the “Think Biology” program and documented coherence among knowledge enrichment, conceptual change, and behavioral change.     

Preschoolers use pedagogical cues to guide radical reorganization of category knowledge

In constructing a conceptual understanding of the world, children must actively evaluate what information is idiosyncratic or superficial, and what represents essential, defining information about kinds and categories. Preschoolers observed identical evidence about a novel object’s function (magnetism) produced in subtly different manners: accidentally, intentionally, or demonstrated communicatively and pedagogically. Only when evidence was explicitly demonstrated for their benefit did children reliably go beyond salient perceptual features (color or shape), to infer function to be a defining property on which to base judgments about category membership. Children did not show this pattern when reasoning about a novel perceptual property, suggesting that a pedagogical communicative context may be especially important for children’s learning about artifact functions. Observing functional evidence in a pedagogical context helps children construct fundamentally different conceptions of novel categories as defined not by superficial appearances but by deeper, functional properties.     

The development of automatic associative processes and children’s false memories

We investigated children’s ability to generate associations and how automaticity of associative activation unfolds developmentally. Children generated associative responses using a single associate paradigm (Experiment 1) or a Deese/Roediger–McDermott (DRM)-like multiple associates paradigm (Experiment 2). The results indicated that children’s ability to generate meaningful word associates, and the automaticity with which they were generated, increased between 5, 7, and 11 years of age. These findings suggest that children’s domain-specific knowledge base and the associative connections among related concepts are present and continue to develop from a very early age. Moreover, there is an increase in how these concepts are automatically activated with age, something that results from domain-general developments in speed of processing. These changes are consistent with the neurodevelopmental literature and together may provide a more complete explanation of the development of memory illusions.     

The cradle of causal reasoning: newborns’ preference for physical causality

Perception of mechanical (i.e. physical) causality, in terms of a cause–effect relationship between two motion events, appears to be a powerful mechanism in our daily experience. In spite of a growing interest in the earliest causal representations, the role of experience in the origin of this sensitivity is still a matter of dispute. Here, we asked the question about the innate origin of causal perception, never tested before at birth. Three experiments were carried out to investigate sensitivity at birth to some visual spatiotemporal cues present in a launching event. Newborn babies, only a few hours old, showed that they significantly preferred a physical causality event (i.e. Michotte's Launching effect) when matched to a delay event (i.e. a delayed launching; Experiment 1) or to a non‐causal event completely identical to the causal one except for the order of the displacements of the two objects involved which was swapped temporally (Experiment 3). This preference for the launching event, moreover, also depended on the continuity of the trajectory between the objects involved in the event (Experiment 2). These results support the hypothesis that the human system possesses an early available, possibly innate basic mechanism to compute causality, such a mechanism being sensitive to the additive effect of certain well‐defined spatiotemporal cues present in the causal event independently of any prior visual experience.     

The susceptibility of young preschoolers to source similarity effects: Confusing story or video events with reality

This study examined children’s tendency to confuse events that varied in source similarity, which was manipulated using different media of event presentation. In Experiment 1, children in two age groups (3- and 4-year-olds and 5- and 6-year-olds) experienced a live presentation of an event, and another event was either heard from a story (low similarity group) or seen on a video (high similarity group). Immediately afterward, the children were asked to monitor the source of the events. The children in the low similarity group produced higher source discrimination scores than did the children in the high similarity group. Overall, the older children were better at source monitoring than were the younger children. In Experiment 2, the procedure was replicated except that the children’s source monitoring was tested after a 4-day delay. When attributing the source of the story or video events, both 3- and 4-year-olds and 5- and 6-year-olds in the low similarity group produced more accurate story or video attributions than did their age mates in the high similarity group. However, when attributing the source of the live events, only the 3- and 4-year-olds evidenced this effect of source similarity. The 5- and 6-year-olds in both the low and high similarity groups performed at ceiling levels for live discriminations.     

Explanation and categorization: How “why?” informs “what?”

Recent theoretical and empirical work suggests that explanation and categorization are intimately related. This paper explores the hypothesis that explanations can help structure conceptual representations, and thereby influence the relative importance of features in categorization decisions. In particular, features may be differentially important depending on the role they play in explaining other features or aspects of category membership. Two experiments manipulate whether a feature is explained mechanistically, by appeal to proximate causes, or functionally, by appeal to a function or goal. Explanation type has a significant impact on the relative importance of features in subsequent categorization judgments, with functional explanations reversing previously documented effects of ‘causal status’. The findings suggest that a feature’s explanatory importance can impact categorization, and that explanatory relationships, in addition to causal relationships, are critical to understanding conceptual representation.     

Concept-procedure interactions in children's addition and subtraction

A 3-week problem-solving practice phase was used to investigate concept-procedure interactions in children’s addition and subtraction. A total of 72 7- and 8-year-olds completed a pretest and posttest in which their accuracy and procedures on randomly ordered problems were recorded along with their reports of using concept-based relations in problem solving and their conceptual explanations. The results revealed that conceptual sequencing of practice problems enhances children’s ability to extend their procedural learning to new unpracticed problems. They also showed that well-structured procedural practice leads to improvement in children’s ability to verbalize key concepts. Moreover, children’s conceptual advances were predicted by their initial procedural skills. These results support an iterative account of the development of basic concepts and key skills in children’s addition and subtraction.     

Children's use of expectations as a source of information in language comprehension

Six studies of children's comprehension of the passive transformation and of the Minimum Distance Principle are reviewed and their results integrated. Children were in kindergarten through Grade 6, inclusive. Expectations about usual grammatical relations (e.g., agent/action combinations) significantly affected children's comprehension: sentences reflecting expectations were understood more often than sentences contradicting children's expressed expectations. Results are discussed within the framework of referential event strategies in understanding spoken language. Limits of the effect of children's expectation on comprehension are described, including general cognitive developmental status, relevant belief systems, and nature of the psycholinguistic task.