The Importance of Discovery in Children's Causal Learning from Interventions

Four-year-olds were more accurate at learning causal structures from their own actions when they were allowed to act first and then observe an experimenter act, as opposed to observing first and then acting on the environment. Children who discovered the causal efficacy of events (as opposed to confirming the efficacy of events that they observed another discover) were also more accurate than children who only observed the experimenter act on the environment; accuracy in the confirmation and observation conditions was at similar levels. These data suggest that while children learn from acting on the environment, not all self-generated action produces equivalent causal learning

Constructing Science

An examination of children's causal reasoning capacities and how those capacities serve as the foundation of their scientific thinking. Young children have remarkable capacities for causal reasoning, which are part of the foundation of their scientific thinking abilities. In Constructing Science, Deena Weisberg and David Sobel trace the ways that young children's sophisticated causal reasoning abilities combine with other cognitive, metacognitive, and social factors to develop into a more mature set of scientific thinking abilities. Conceptualizing scientific thinking as the suite of skills that allows people to generate hypotheses, solve problems, and explain aspects of the world, Weisberg and Sobel argue that understanding how this capacity develops can offer insights into how we can become a more scientifically literate society. Investigating the development of causal reasoning and how it sets the stage for scientific thinking in the elementary school years and beyond, Weisberg and Sobel outline a framework for understanding how children represent and learn causal knowledge and identify key variables that differ between causal reasoning and scientific thinking. They present empirical studies suggesting ways to bridge the gap between causal reasoning and scientific thinking, focusing on two factors: contextualization and metacognitive thinking abilities. Finally, they examine children's explicit understanding of such concepts as science, learning, play, and teaching

Developmental Trajectories in Diagnostic Reasoning: Understanding Data Are Confounded Develops Independently of Choosing Informative Interventions to Resolve Confounded Data

Two facets of diagnostic reasoning related to scientific thinking are recognizing the difference between confounded and unconfounded evidence and selecting appropriate interventions that could provide learners the evidence necessary to make an appropriate causal conclusion (i.e., the control-of-variables strategy). The present study investigates both these abilities in 3- to 6-year-old children (N = 57). We found both competence and developmental progress in the capacity to recognize that evidence is confounded. Similarly, children performed above chance in some tasks testing for the selection of a controlled test of a hypothesis. However, these capacities were unrelated, suggesting that preschoolers' nascent understanding of the control-of-variables strategy may not be driven by a metacognitive understanding that confounded evidence does not support a unique causal conclusion, and requires further investigation

Sixteen-month-olds comprehend unanchored absent reference

A nascent understanding of absent reference emerges around 12months: provided with rich contextual support, infants look and pointto the location of a displaced object. When can infants understandabsent reference without contextual support? Using a proceduremodified from Hendrickson and Sundara (2017), 13- and 16-month-olds first listened to utterances containing familiar target words, whileviewing a checkerboard. Then, two objects – a referent and a distractor(e.g., a cup and a shoe) – appeared on the screen. Only 16-month-oldsdemonstrated a reliable looking preference for the referents, suggestingthat listening to the utterances activated their mental images of thereferents. These results establish that at 16 months, infants comprehendreference to absent entities without any contextual support

Bayes and Blickets: Effects of Knowledge on Causal Induction in Children and Adults

People are adept at inferring novel causal relations, even from only a few observations. Prior knowledge about the probability of encountering causal relations of various types and the nature of the mechanisms relating causes and effects plays a crucial role in these inferences. We test a formal account of how this knowledge can be used and acquired, based on analyzing causal induction as Bayesian inference. Five studies explored the predictions of this account with adults and 4-year-olds, using tasks in which participants learned about the causal properties of a set of objects. The studies varied the two factors that our Bayesian approach predicted should be relevant to causal induction: the prior probability with which causal relations exist, and the assumption of a deterministic or a probabilistic relation between cause and effect. Adults’ judgments (Experiments 1, 2, and 4) were in close correspondence with the quantitative predictions of the model, and children’s judgments (Experiments 3 and 5) agreed qualitatively with this account.Mitsubishi Electronic Research LaboratoriesUnited States. Air Force Office of Sponsored ResearchMassachusetts Institute of Technology. Paul E. Newton ChairJames S. McDonnell Foundatio

Monocytes and tissue factor promote thrombosis in a murine model of oxygen deprivation.

This is the published version. Copyright 1997 American Society for Clinical Investigation.Clinical conditions associated with local or systemic hypoxemia can lead to prothrombotic diatheses. This study was undertaken to establish a model of whole-animal hypoxia wherein oxygen deprivation by itself would be sufficient to trigger tissue thrombosis. Furthermore, this model was used to test the hypothesis that hypoxia-induced mononuclear phagocyte (MP) recruitment and tissue factor (TF) expression may trigger the local deposition of fibrin which occurs in response to oxygen deprivation. Using an environmental chamber in which inhaled oxygen tension was lowered to 6%, hypoxic induction of thrombosis was demonstrated in murine pulmonary vasculature by 8 h based upon: (a) immunohistologic evidence of fibrin formation in hypoxic lung tissue using an antifibrin antibody, confirmed by 22.5-nm strand periodicity by electron microscopy; (b) immunoblots revealing fibrin gamma-gamma chain dimers in lungs from hypoxic but not normoxic mice or hypoxic mice treated with hirudin; (c) accelerated deposition of 125I-fibrin/fibrinogen and 111In-labeled platelets in the lung tissue of hypoxic compared with normoxic animals; (d) reduction of tissue 125I-fibrin/fibrinogen accumulation in animals which had either been treated with hirudin or depleted of platelets before hypoxic exposure. Because immunohistochemical analysis of hypoxic pulmonary tissue revealed strong MP staining for TF, confirmed by increased TF RNA in hypoxic lungs, and because 111In-labeled murine MPs accumulated in hypoxic pulmonary tissue, we evaluated whether recruited MPs might be responsible for initiation of hypoxia-induced thrombosis. This hypothesis was supported by several lines of evidence: (a) MP depletion before hypoxia reduced thrombosis, as measured by reduced 125I-fibrin/fibrinogen deposition and reduced accumulation of cross-linked fibrin by immunoblot; (b) isolated murine MPs demonstrated increased TF immunostaining when exposed to hypoxia; and (c) administration of an anti-rabbit TF antibody that cross-reacts with murine TF decreased 125I-fibrin/fibrinogen accumulation and cross-linked fibrin accumulation in response to hypoxia in vivo. In summary, these studies using a novel in vivo model suggest that MP accumulation and TF expression may promote hypoxia-induced thrombosis

Importance of continued activation of thrombin reflected by fibrinopeptide A to the efficacy of thrombolysis

Factors responsible for initial success or failure of coronary thrombolysis and persistent recanalization or early reocclusion have not been thoroughly elucidated. Both adequate initial clot lysis and preclusion of rethrombosis are required. Failure may reflect clot lysis followed immediately or somewhat later by rethrombosis. To determine whether differences in the intensity and persistence of the activation of thrombin are determinants of success or failure of recanalization, plasma fibrinopeptide A, a fibrinogen product liberated by thrombin, was serially assayed in 19 patients treated with intravenous streptokinase. In patients exhibiting recanalization (n = 9), plasma fibrinopeptide A decreased after administration of streptokinase but before administration of heparin. In patients without initially apparent recanalization, fibrinopeptide A increased, suggesting ongoing thrombosis, and subsequently decreased promptly after heparin. In patients with initial recanalization followed by overt reocclusion the pattern was different. Despite recanalization, fibrinopeptide A continued to rise markedly. Elevations persisted despite administration of heparin. Thus, inhibition of activation of thrombin is associated with successful recanalization. Conversely, persistent activation of thrombin may be a predisposing factor to both apparent initial failure of recanalization and nvprt early reocclusion

Inference with interference between units in an fMRI experiment of motor inhibition

An experimental unit is an opportunity to randomly apply or withhold a treatment. There is interference between units if the application of the treatment to one unit may also affect other units. In cognitive neuroscience, a common form of experiment presents a sequence of stimuli or requests for cognitive activity at random to each experimental subject and measures biological aspects of brain activity that follow these requests. Each subject is then many experimental units, and interference between units within an experimental subject is likely, in part because the stimuli follow one another quickly and in part because human subjects learn or become experienced or primed or bored as the experiment proceeds. We use a recent fMRI experiment concerned with the inhibition of motor activity to illustrate and further develop recently proposed methodology for inference in the presence of interference. A simulation evaluates the power of competing procedures.Comment: Published by Journal of the American Statistical Association at http://www.tandfonline.com/doi/full/10.1080/01621459.2012.655954 . R package cin (Causal Inference for Neuroscience) implementing the proposed method is freely available on CRAN at https://CRAN.R-project.org/package=ci