Children's use of reasoning by exclusion to infer objects' identities in working memory

20-month-olds can use negative evidence while learning word meanings

Decades of research in psychology have built models and theoretical assumptions about language development evaluating how children extract information from positive evidence to learn the meanings of novel words. In the present set of studies, we evaluated whether children can also consider negative evidence, information about what a word cannot refer to. Across two experiments (n = 73), we show that English-learning 20-month-olds can use negative evidence in the form of negative sentences (e.g., "This is not a danu") to constrain their interpretation of a novel word meaning ("danu"). These findings raise the possibility that learning word meanings through positive evidence alone, while possible, may not be the most accurate characterization of the word learning process and invite further developments of current word learning theories and models that incorporate negative evidence.

To add or to remove? The role of working memory updating in preschool children's non-symbolic arithmetic abilities between addition and subtraction

Early computational capacity sets the foundation for mathematical learning. Preschool children have been shown to perform both non-symbolic addition and subtraction problems. However, it is still unknown how different operations affect the representational precision of the non-symbolic arithmetic solutions. The current study compared 83 4- and 5-year-olds' ability to solve non-symbolic addition and subtraction problems and examined the role of working memory underlying the two arithmetic processes. In the task, children were shown two sets of arrays that were sequentially occluded and were asked to either sum the arrays up (addition) or remove one array from the other (subtraction). The solution was then compared with a visible array. Children also completed two working memory tasks to measure their working memory storage and updating abilities. Results showed that children's representational precision in addition was higher than that in subtraction. Although children's performance in both arithmetic operations were associated with working memory updating, solving subtractive problems imposed additional cognitive resources in working memory updating. These findings reveal early developmental differences between addition and subtraction. Children's computational capacity in both addition and subtraction develops early in childhood, and the operation in subtraction demands more mental manipulation in working memory.

Three- and four-year-old children represent mutually exclusive possible identities

How do children think about and plan for possible outcomes of events that could happen in the future? Previous work that has investigated children's ability to think about mutually exclusive possibilities has largely focused on children's reasoning about one type of possibility-the possible locations of an object. Here, we investigated children's reasoning about another type of possibility-mutually exclusive possible identities. In two experiments (N = 201 U.S. 3- and 4-year-olds), children were told that two animal characters (e.g., a bunny and a monkey) were going to take turns sliding down a playground slide. Children were told that the animals wanted to eat their favorite foods (e.g., carrots and bananas, respectively) as soon as they got to the bottom of the slide. In an Unambiguous Identity condition, we told children the identity of the animal that would slide down. In an Ambiguous Identity condition, we told children that which animal would slide down first was unknown. To examine children's representations of possible identities, we asked children to "get snack ready." We found that children in the Unambiguous Identity condition selected only one of the snacks (i.e., the favorite snack of the animal they were told would slide down), whereas children in the Ambiguous Identity condition selected both snacks, suggesting that they were accounting for both possible identities. These results extend the literature on the development of modal reasoning to include reasoning about possible identities and suggest that this ability may be available to children as young as 3 years.

"Catastrophic" set size limits on infants' capacity to represent objects: A systematic review and Bayesian meta-analysis

Decades of research has revealed that humans can concurrently represent small quantities of three-dimensional objects as those objects move through space or into occlusion. For infants (but not older children or adults), this ability apparently comes with a significant limitation: when the number of occluded objects exceeds three, infants experience what has been characterized as a "catastrophic" set size limit, failing to represent even the approximate quantity of the hidden array. Infants' apparent catastrophic representational failures suggest a significant information processing limitation in the first years of life, and the evidence has been used as support for prominent theories of the development of object and numerical cognition. However, the evidence for catastrophic failure consists of individual small-n experiments that use null hypothesis significance testing to obtain null results (i.e., p > 0.05). Whether catastrophic representational failures are robust or reliable across studies, methods, and labs is not known. Here we report a systematic review and Bayesian meta-analysis to examine the strength of the evidence in favor of catastrophic representational failures in infancy. Our analysis of 22 experiments across 12 reports, with a combined total of n = 367 infants aged 10-20 months, revealed strong support for the evidence for catastrophic set size limits. A complementary analysis found moderate support for infants' success when representing fewer than four objects. We discuss the implications of our findings for theories of object and numerical cognitive development. RESEARCH HIGHLIGHTS: Previous work has suggested that infants are unable to concurrently represent four or more objects-a "catastrophic" set size limit. We reviewed this work and conducted a Bayesian meta-analysis to examine the robustness of this limit across individual small-n experiments. We found strong support for the evidence for catastrophic set size limits, and moderate support for infants' success when representing fewer than four objects.