Context-sensitive heuristics in statistical reasoning

Previous work has shown that people use anchor-and-adjust heuristics to forecast future data points from previous ones in the same series. We report three experiments that show that they use different versions of this heuristic for different types of series. To forecast an untrended series, our subjects always took a weighted average of the long-term mean of the series and the last data point. In contrast, the way that they forecast a trended series depended on the serial dependences in it. When these were low, people forecast by adding a proportion of the last difference in the series to the last data point. When stronger serial dependences made this difference less similar to the next one, they used a version of the averaging heuristic that they employed for untrended series. This could take serial dependences into account and included a separate component for trend. These results suggest that people use a form of the heuristic that is well adapted to the nature of the series that they are forecasting. However, we also found that the size of their adjustments tended to be suboptimal. They overestimated the degree of serial dependence in the data but underestimated trends. This biased their forecasts.     

THE DILEMMA OF ERROR AND ACCURACY: AN EXPLORATION

This paper reports on the research on error and accuracy within the realms of constructivism, reading, and writing, and describes an exploratory study of teacher perceptions of approaches to addressing error and accuracy in literacy instruction. Findings demonstrate that teachers who self-reported that they were developing constructivist approaches to classroom instructional practices had contradictory beliefs about dealing with reading and writing errors. There were also contradictory beliefs about addressing reading and writing errors with more- and less-able readers and writers. The teachers were solid in their conviction that students' inaccurate constructions of knowledge should be corrected through inquiry, but were unable to provide examples of instances in which they had done so.     

LEVELS OF CATEGORIZATION AND SIGHT WORD ACQUISITION

Prereading first graders were trained in a group of six sight words drawn from superordinate, basic, and subordinate levels of categorization as well as from a list of frequency control words. After teaching the selected to the students following an interference task, the students were posttested for immediate recall of the previously learned words. They were also tested for recall after a forty‐eight hour delay. Results of the posttesting indicate that the level of categorization from which a word is drawn affects its learnability as a sight word. Students demonstrated that basic level words were easier to learn and recall, regardless of their frequencies.