Darcy Hallett

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The accuracy and variability of response times (RTs) collected on stock Apple Macintosh computers using USB keyboards was assessed. A photodiode detected a change in the screen's luminosity and triggered a solenoid that pressed a key on the keyboard. The RTs collected in this way were reliable, but could be as much as 100 ms too long. The standard deviation(More)
Multiplicative reasoning is required in different contexts in mathematics: it is necessary to understand the concept of multipart units, involved in learning place value and measurement, and also to solve multiplication and division problems. Measures of hearing children's multiplicative reasoning at school entry are reliable and specific predictors of(More)
How does culture impact individual’s cognitive complexity? This article reviews evidence suggesting that the relationship between culture and cognitive complexity depends upon the nature of the situation in which complexity is expressed. In addition, two new investigations are summarized. One study reveals that individuals from different cultures are(More)
The effect of 500 mM NaCl on the growth, and phosphatase production of a Citrobacter sp. was investigated. Although growth was retarded, phosphatase production was enhanced by 50%. Relief from osmotic stress using the osmoprotectant glycine betaine gave normal growth, but phosphatase activity was reduced. The Citrobacter sp. ceased to grow following a shift(More)
Math anxiety has been defined as unpleasant feelings of tension and anxiety that hinder the ability to deal with numbers and math in a variety of situations. Although many studies have looked at situational and demographic factors associated with math anxiety, little research has looked at the self-reported experiences with math that are associated with(More)
In time-place learning (TPL) paradigms animals are thought to form tripartite memory codes consisting of the spatiotemporal characteristics of biologically significant events. In Phase I, rats were trained on a modified TPL task in which either the spatial or temporal component was constant, while the other component varied randomly. If the memory codes are(More)
While previous research has investigated the ability of animals to learn the spatial and temporal contingencies of biologically significant events (known as time-place learning), this ability has not been studied in humans. Children ranging from 5 to 10 years old were tested on a modified interval time-place learning task using a touchscreen computer.(More)
Recent research on children's conceptual and procedural knowledge has suggested that there are individual differences in the ways that children combine these two types of knowledge across a number of mathematical topics. Cluster analyses have demonstrated that some children have more conceptual knowledge, some children have more procedural knowledge, and(More)
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