Children's ascriptions of property rights with changes of ownership

Ownership is not a “natural” property of objects, but is determined by human intentions. Facts about who owns what may be altered by appropriate decisions. However, young children often deny the efficacy of transfer decisions, asserting that original owners retain rights to their property. In Experiment 1, 4–5-year-old and 7–8-year-old children and adults were asked to resolve disputes between initial owners and various types of receivers (finders, borrowers, buyers). Experiment 2 involved disputes both before and after transfers of ownership. At all ages participants privileged owners over non-owners and accepted the effectiveness of property transfers. Overall, children's intuitions about property rights were similar to those of adults. Observed differences may reflect older participants’ willingness to segregate property rights from other considerations in assessing the acceptability of actions.     

Sample selection and inductive generalization

In two experiments with adults (N=126), we examined the influence of sampling procedure on inductive generalization. In predicate sampling, participants learned the category identity of individuals known to possess some property. In subject sampling, individuals selected for category identity were discovered to possess a novel property. In both experiments, sampling procedure influenced induction. Predicate sampling resulted in very narrow generalization, whereas subject sampling yielded a fairly high and constant rate of projection. Differences in confidence of generalizations were also observed. Conditions in which evidence was described as randomly sampled from a collection of animals yielded a consistent decrease in projections as predicted by similarity-based models. The results are presented as support for an evidence-based view of induction.     

The role of maltreatment experience in children's understanding of the antecedents of emotion

The ability to understand the causes and likely triggers of emotions has important consequences for children's adaptation to their social environment. Yet, little is currently known about the processes that contribute to the development of emotion understanding. To assess how well children understood the antecedents of emotional reactions in others, we presented children with a variety of emotional situations that varied in outcome and equivocality. Children were told the emotional outcome and asked to rate whether a situation was a likely cause of such an outcome. We tested the effects of maltreatment experience on children's ability to map emotions to their eliciting events and their understanding of emotion–situation pairings. The present data suggest that typically developing children are able to distinguish between common elicitors of negative and positive events. In contrast, children who develop within maltreating contexts, where emotions are extreme and inconsistent, interpret positive, equivocal, and negative events as being equally plausible causes of sadness and anger. This difference in maltreated children's reasoning about emotions suggests a critical role of experience in aiding children's mastery of the structure of interpersonal discourse.     

Tumor Screening in Beckwith-Wiedemann Syndrome: Parental Perspectives

Children with Beckwith-Wiedemann Syndrome (BWS) and Isolated Hemihypertrophy (IHH) are at an increased risk for developing tumors. Tumor screening in this population is currently being reassessed by several groups and the effect on patients and patient-families has been argued both as a reason to screen and not to screen. Parental perspectives on this topic have never been systematically addressed for the BWS population. Here, we conducted a parent-based survey to evaluate knowledge and attitudes toward tumor screening in patients affected by BWS/IHH. A total of 261 surveys were completed. Overall, parents reported that screening decreased their worry and did not feel that screening increased worry or created a burden. This effect was observed across various demographic variables and other factors examined. Almost all significant differences observed could be attributed to parental knowledge of tumor risk. Parents who correctly identified their child’s tumor risk were more likely to agree with stratified screening recommendations according to BWS type and risk, and were less likely to feel worried if recommendations were changed. These results highlight the need to educate families about their child’s genetic type and tumor risk in order to facilitate an informed decision about tumor screening.     

Population of linear experts: knowledge partitioning and function learning

Knowledge partitioning is a theoretical construct holding that knowledge is not always integrated and homogeneous but may be separated into independent parcels containing mutually contradictory information. Knowledge partitioning has been observed in research on expertise, categorization, and function learning. This article presents a theory of function learning (the population of linear experts model--POLE) that assumes people partition their knowledge whenever they are presented with a complex task. The authors show that POLE is a general model of function learning that accommodates both benchmark results and recent data on knowledge partitioning. POLE also makes the counterintuitive prediction that a person's distribution of responses to repeated test stimuli should be multimodal. The authors report 3 experiments that support this prediction.     

Error-driven knowledge restructuring in categorization

Knowledge restructuring occurs when people shift to a new strategy or representation during learning. Although knowledge restructuring can frequently be experimentally encouraged, there are instances in which people resist restructuring and continue to use an expedient but imperfect initial strategy. The authors report 3 category learning experiments that reconciled those conflicting outcomes by postulating that, for restructuring to occur, learners must be dissatisfied with their knowledge and a usable alternative must be available. In line with expectation, restructuring was elicited only when an alternative strategy was pointed out and when people's initial expedient strategy entailed performance error. Neither error nor information about the alternative strategy by itself was sufficient to induce restructuring.     

An inverse base rate effect with continuously valued stimuli

It is well known that people do not always make normative use of information about relative frequencies of categories when making categorical judgments. The "inverse base rate" effect (Medin & Edelson, 1988) is a typical example of this: Subjects violate normative reasoning principles by assigning certain ambiguous stimuli as belonging to the less frequent of two categories, rather than to the more common category. This effect has been explained as being due to the shifting of attention from shared stimulus features to distinctive features during learning. When stimuli are defined by values along continuous dimensions, rather than by the presence and absence of features, then attention could shift between dimensions or between values, or both. In three experiments, base rate differences were used to determine the way in which attention is shifted during learning about stimuli with continuously valued dimensions. Simulation modeling shows that the results are consistent with the movement of attention both between and within stimulus dimensions.