Andrew G. Young

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The Cognitive Reflection Test (CRT) is a widely used measure of adults’ propensity to engage in reflective analytic thought. The CRT is strongly predictive of many diverse psychological factors but unsuitable for use with developmental samples. Here, we examined a children’s CRT, the CRT–Developmental (CRT–D), and investigated its predictive utility in the domains of science and mathematics. School-age children (N = 152) completed the CRT–D, measures of executive functioning, measures of rational thinking, and measures of vitalist-biology and mathematical-equivalence concepts. CRT–D performance predicted conceptual understanding in both domains after we adjusted for children’s age, executive functioning, and rational thinking. These findings suggest that cognitive reflection supports conceptual knowledge in early science and mathematics and, moreover, demonstrate the theoretical and practical importance of children’s cognitive reflection. The CRT–D will allow researchers to investigate the development, malleability, and consequences of children’s cognitive reflection.

What influences children's normative judgments of conventional rules at different points in development? The current study explored the effects of two contextual factors on children's normative reasoning: the way in which the rules were learned and whether the rules apply to the self or others. Peer dyads practiced a novel collaborative board game comprising two complementary roles. Dyads were either taught both the prescriptive (i.e., what to do) and proscriptive (i.e., what not to do) forms of the rules, taught only the prescriptive form of the rules, or created the rules themselves. Children then judged whether third parties were violating or conforming to the rules governing their own roles and their partner's roles. Early school-aged children's (6- to 7-year-olds; N = 60) normative judgments were strongest when they had been taught the rules (with or without the proscriptive form), but were more flexible for rules they created themselves. Preschool-aged children's (4- to 5-year-olds; N = 60) normative judgments, however, were strongest when they were taught both the prescriptive and proscriptive forms of the rules. Additionally, preschoolers exhibited stronger normative judgments when the rules governed their own roles rather than their partner's roles, whereas school-aged children treated all rules as equally normative. These results demonstrate that children's normative reasoning is contingent on contextual factors of the learning environment and, moreover, highlight 2 specific areas in which children's inferences about the normativity of conventions strengthen over development. (PsycINFO Database Record

Teachers’ gestures are an integral part of their instructional communication. In this study, we provided a teacher with a tutorial about ways to use gesture in connecting ideas in mathematics instruction, and we asked the teacher to teach sample lessons about slope and intercept before and after this tutorial. In response to the tutorial, the teacher enhanced his communication about links between ideas by increasing the frequency with which he expressed linked ideas multi-modally (i.e., using both speech and gesture), and by increasing the frequency with which he used simultaneous gestures to linked ideas. We then presented videos of a lesson the teacher provided before the tutorial (the baseline lesson) and one he provided after the tutorial (the enhanced-gesture lesson) to 42 seventh-grade students and assessed their learning. Students who received the enhanced-gesture lesson displayed greater learning about y-intercept than did students who received the baseline lesson. Thus, students learned more when their teacher had learned to gesture effectively.

When children evaluate evidence and make causal inferences, they are sensitive to the social context in which data are generated. This study investigated whether children learn more from evidence generated by an agent who agrees with them or from one who disagrees with them. Children in two age groups (5- and 6-year-olds and 9- and 10-year-olds) observed the functioning of a machine that lit up and played music in the presence of certain objects. After endorsing one of two plausible causal hypotheses, children observed a puppet either agree or disagree with their own hypotheses. The puppet then generated a further piece of evidence that confirmed, disconfirmed, or was neutral with respect to the children's hypotheses. When they were later asked to make causal inferences about objects they did not directly observe, children in both age groups responded differentially to identical evidence depending on whether the agent agreed or disagreed, and they often drew stronger inferences in response to disagreement. In addition, older children were particularly sensitive to disagreement when the evidence was ambiguous. Our results suggest that children consider the relationship between their own and others' hypotheses when evaluating evidence that others generate.

Polyploidy is a widespread feature of some plants that allows for rapid speciation and occurs widely in Poaceae. However, there have been few studies of Australian native grasses reporting the distribution patterns of cytotypes and examining the potential role of different cytotypes in adaptation. We determined chromosome number for 48, 113, 8, 43 and 33 plants of Austrodanthonia bipartita (Link) H.P.Linder, A. caespitosa (Gaudich.) H.P.Linder, A. eriantha (Lindl.) H.P.Linder, A. fulva (Vickery) H.P.Linder and A. setacea (R.Br.) H.P.Linder, respectively, representing 28 wild populations collected in central western New South Wales. A widespread distribution is reported for tetraploids (2n = 48), whereas diploids (2n = 24) and a limited number of hexaploids (2n = 72) appear to be associated with northern and western populations. In all populations, coexistent cytotypes were found, although tetraploids were the most widespread cytotype for the most commonly occurring species, A. caespitosa. The occurrence of low frequencies of putative intermediate cytotypes, particularly triploids, in all five species provides evidence for inter-specific hybridisation and/or intra-specific crossing between cytotypes. The lack of common ecological factors (climate, edaphic or micro-site) that clearly distinguish diploid from tetraploid A. caespitosa plants provides further evidence for hybridisation between cytological races of this species.

Young children are surprisingly judicious imitators, but there are also times when their reproduction of others' actions appears strikingly illogical. For example, children who observe an adult inefficiently operating a novel object frequently engage in what we termoverimitation, persistently reproducing the adult's unnecessary actions. Although children readily overimitate irrelevant actions that even chimpanzees ignore, this curious effect has previously attracted little interest; it has been assumed that children overimitate not for theoretically significant reasons, but rather as a purely social exercise. In this paper, however, we challenge this view, presenting evidence that overimitation reflects a more fundamental cognitive process. We show that children who observe an adult intentionally manipulating a novel object have a strong tendency to encode all of the adult's actions as causally meaningful, implicitly revising their causal understanding of the object accordingly. This automatic causal encoding process allows children to rapidly calibrate their causal beliefs about even the most opaque physical systems, but it also carries a cost. When some of the adult's purposeful actions are unnecessary—even transparently so—children are highly prone to mis-encoding them as causally significant. The resulting distortions in children's causal beliefs are the true cause of overimitation, a fact that makes the effect remarkably resistant to extinction. Despite countervailing task demands, time pressure, and even direct warnings, children are frequently unable to avoid reproducing the adult's irrelevant actions because they have already incorporated them into their representation of the target object's causal structure.

Genetics, Demography and Viability of Fragmented Populations - October 2000