Snoddy (1926) revisited: time scales of motor learning

The authors investigated the time scales of the learning of a mirror-tracing task to reexamine G. S. Snoddy's (1926) original claim and the received theoretical view (A. Newell & P. S. Rosenbloom, 1981) that motor learning follows a power law. Adult participants (N = 16) learned the tracing task in either a normal or a reversed visual-image condition over 5 consecutive days of practice and then performed 1 day of practice 1 week later and again 1 month later. The reversed-image group's performance was poorer than that of the normal-image group throughout the practice. An exponential was the best fitting function on individual data, but the power-law function was the best fit on the group-averaged data. The findings provided preliminary evidence that 2 characteristic time scales, (a) fast, dominated by warm-up, and (b) slow, dominated by persistent change, capture individuals' performance in the learning of the mirror-tracing task.     

Abortion and Health Care Chaplaincy in Australia

This paper summarizes the results gained from quantitative and qualitative research involving 327 Australian health care chaplains with regard to their involvement in abortion issues within the health care context. The findings indicate that approximately 20% of surveyed chaplains had provided some form of pastoral intervention to patients and/or their families dealing with issues of abortion and that approximately 10% of chaplains had assisted clinical staff with issues concerning abortion. There was found to be no-statistically significant difference with regard to the number of catholic chaplains compared with protestant chaplains or staff chaplains compared with volunteer chaplains involved in abortion issues. Analysis using the WHO Pastoral Intervention codings highlighted a variety of issues encountered by chaplains and the non-judgmental pastoral care used by chaplains when assisting those dealing with abortion. Some implications of this study with respect to patient and clinical staff support are suggested. Dr. Lindsay Carey, M.App.Sc., Ph.D.: National Research Fellow, Australian Health & Welfare Chaplains Association & Faculty Associate, Palliative Care, School of Public Health, La Trobe University, Melbourne, Australia. Dr. Christopher Newell, AM, Ph.D.: Associate Professor, School of Medicine, University of Tasmania, Hobart, Australia.     

Missing the target: A reply to Koehler & Macchi (2009)

Koehler and Macchi 2009 criticize the experiments presented in Newell, Mitchell, and Hayes 2008 as being “virtually irrelevant” to exemplar cuing theory. This reply addresses that interpretation and argues that the experiments dealt with issues at the heart of the theory and provided evidence highly relevant to understand how people think about low‐probability events. The role of the ‘target’ in probabilistic statements is examined, highlighting the need for further theoretical and empirical clarification of the concept. The remaining specific criticisms raised in the commentary are discussed as well. Copyright © 2009 John Wiley & Sons, Ltd.     

Think, blink or sleep on it? The impact of modes of thought on complex decision making

This paper examines controversial claims about the merit of "unconscious thought" for making complex decisions. In four experiments, participants were presented with complex decisions and were asked to choose the best option immediately, after a period of conscious deliberation, or after a period of distraction (said to encourage "unconscious thought processes"). In all experiments the majority of participants chose the option predicted by their own subjective attribute weighting scores, regardless of the mode of thought employed. There was little evidence for the superiority of choices made "unconsciously", but some evidence that conscious deliberation can lead to better choices. The final experiment suggested that the task is best conceptualized as one involving "online judgement" rather than one in which decisions are made after periods of deliberation or distraction. The results suggest that we should be cautious in accepting the advice to "stop thinking" about complex decisions.     

The testing effect: The role of feedback and collaboration in a tertiary classroom setting

Successful retrieval on a test compared to just re‐studying material improves long‐term retention—a phenomenon called the ‘testing effect’. This study investigated the role of feedback and collaborative testing on the retention of course material in a tertiary educational setting. Tested material was better retained relative to non‐tested material (testing effect), and feedback facilitated correction of errors. Group testing produced higher performance on the initial, but not final test performance, compared to individual testing. This set of findings suggests that to encourage long‐term retention, educators should utilise individual formative testing with feedback; theoretical implications are also discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Postural coordination patterns as a function of dynamics of the support surface

The present study investigated the compensatory postural coordination patterns that emerge in the face of dynamic changes in the surface of support. Adult subjects stood on a moving platform that was sinusoidally translated in the anterior-posterior direction. The frequency and amplitude of the support surface translation were manipulated over a wide range of parameter values. The results revealed that as the frequency of platform motion increased, the postural system systematically exploited the available joint-space degrees of freedom and generated four distinct postural coordination modes (a rigid mode --> ankle mode --> ankle-hip mode --> ankle-hip-knee mode). It appears that upright standing posture has a small set of coordination patterns that are particular to the dynamics of the surface of support.     

Age differences in noise and variability of isometric force production.

This study examined whether age-related improvements observed in the motor performance of children result from a reduction of noise in the output of the sensori-motor system. Children ages 6, 8, and 10 years and young adults (N = 48, 12 per group) performed continuous, constant isometric force contractions with the index finger at four different force levels with and without visual feedback. The results revealed that: (a) performance improved with increases in age, (b) the force output signal exhibited increased irregularity and a more broadband frequency profile with increases in age under conditions with feedback, and (c) there were no age differences in the irregularity of the force signal and smaller age differences in the frequency profiles under conditions without feedback. It is proposed that the age-related enhancements in performance throughout childhood are primarily due to a more appropriate mapping of the organization of the sensori-motor system to the task constraints rather than to reduction of system noise.     

Noncategorical approaches to feature prediction with uncertain categories

In four experiments, we investigated how people make feature predictions about objects whose category membership is uncertain. Artificial visual categories were presented and remained in view while a novel instance with a known feature, but uncertain category membership was presented. All four experiments showed that feature predictions about the test instance were most often based on feature correlations (referred to as feature conjunction reasoning). Experiment 1 showed that feature conjunction reasoning was generally preferred to category-based induction in a feature prediction task. Experiment 2 showed that people used all available exemplars to make feature conjunction predictions. Experiments 3 and 4 showed that the preference for predictions based on feature conjunction persisted even when category-level information was made more salient and inferences involving a larger number of categories were required. Little evidence of reasoning based on the consideration of multiple categories (e.g., Anderson, (Psychological Review, 98:409–429, 1991)) or the single, most probable category (e.g., Murphy & Ross, (Cognitive Psychology, 27:148–193, 1994)) was found.     

Is strong reciprocity really strong in the lab, let alone in the real world?

We argue that standard experiments supporting the existence of "strong reciprocity" do not represent many cooperative situations outside the laboratory. More representative experiments that incorporate "earned" rather than "windfall" wealth also do not provide evidence for the impact of strong reciprocity on cooperation in contemporary real-life situations or in evolutionary history, supporting the main conclusions of the target article.