Sunk-cost effects on purely behavioral investments

Although the sunk-cost effect is a well-documented psychological phenomenon in monetary investments, existing literature investigating behavioral investments (e.g., time, effort) has not replicated this effect except when such investments relate to monetary values. The current explanation for this discrepancy proposes that purely behavioral sunk-cost effects are unlikely to be observed because they are difficult to book, track, and balance in a mental account. Conversely, we argue that, through an effort-justification mechanism, people account for the amount of behavioral resources invested when selecting an alternative, in which case they may fall prey to purely behavioral sunk-cost effects. The results of two experiments support this prediction. Because many decisions involve behavioral investments, behavioral sunk-cost effects should be pervasive psychological phenomena.     

Specialization effect and its influence on memory and problem solving in expert chess players

Expert chess players, specialized in different openings, recalled positions and solved problems within and outside their area of specialization. While their general expertise was at a similar level, players performed better with stimuli from their area of specialization. The effect of specialization on both recall and problem solving was strong enough to override general expertise—players remembering positions and solving problems from their area of specialization performed at around the level of players 1 standard deviation (SD) above them in general skill. Their problem-solving strategy also changed depending on whether the problem was within their area of specialization. When it was, they searched more in depth and less in breadth; with problems outside their area of specialization, the reverse. The knowledge that comes from familiarity with a problem area is more important than general purpose strategies in determining how an expert will tackle it. These results demonstrate the link in experts between problem solving and memory of specific experiences and indicate that the search for context-independent general purpose problem-solving strategies to teach to future experts is unlikely to be successful.     

What–Where–When memory in magpies (Pica pica)

Some animals have been shown to be able to remember which type of food they hoarded or encountered in which location and how long ago (what–where–when memory). In this study, we test whether magpies (Pica pica) also show evidence of remembering these different aspects of a past episode. Magpies hid red- and blue-dyed pellets of scrambled eggs in a large tray containing wood shavings. They were allowed to make as many caches as they wanted. The birds were then returned either the same day or the next day to retrieve the pellets. If they returned the same day, one colour of pellets was replaced with wooden beads of similar size and colour, while if they returned the next day this would happen to the other colour. Over just a few trials, the birds learned to only search for the food pellets, and ignore the beads, of the appropriate colour for the given retention interval. A probe trial in which all items were removed showed that the birds persisted in searching for the pellets and not the beads. This shows that magpies can remember which food item they hoarded where, and when, even if the food items only differ from each other in their colour and are dispersed throughout a continuous caching substrate.     

Mule cognition: a case of hybrid vigour?

This study compares the behaviour of the mule (Equus asinus × Equus caballus) with that of its parent species to assess the effects of hybridization on cognition. Six mules, six ponies (E. caballus) and six donkeys (E. asinus) were given a two choice visual discrimination learning task. Each session consisted of 12 trials and pass level was reached when subjects chose the correct stimulus for at least 9 out of the 12 trials in three consecutive sessions. A record was made of how many pairs each subject learnt over 25 sessions. The mules’ performance was significantly better than that of either of the parent species (Kruskal-Wallis: H_x = 8.11, P = 0.017). They were also the only group to learn enough pairs to be able to show a successive reduction in the number of sessions required to reach criterion level. This study provides the first empirical evidence that the improved characteristics of mules may be extended from physical attributes to cognitive function.     

遗传、环境和青少年的吸烟饮酒行为：芬兰双生子研究的回溯与前瞻

本文介绍的两个“芬兰双生子（Finn Twin）”研究是对10个出生组的青少年双生子及其家庭的长期跟踪研究。本文概述了这两个项目对遗传与环境的关联和互动对吸烟饮酒行为影响的研究。这些研究的结果提示个体差异对吸烟饮酒行为的长期变动的影响受到兄弟姐妹互动、同伴互动以及父母教养方式的调节。环境对吸烟饮酒的影响主要表现在学校、居住社区与家庭环境的差异上。环境与遗传影响的程度和持久度有城乡差异。遗传的影响受居住社区的制约。多阶段模型的分析揭示了遗传与环境的互动对这些行为的演变（从试吸试饮到发展到滥用）的动态的影响,遗传似乎对吸烟饮酒的共同轨迹更有影响。这些结果对今后本项目对这约1万对芬兰成年双生子的分子遗传学研究提供了有益的线索     

Support vector machines categorize the scaling of human grip configurations

In previous work (Cesari & Newell, 2002), we used a graphical dimensional analysis to show that grip transitions obey the body-scaled relation K = lnL(o) + InM(o)h/(a + bM(h) + cL(h)), where L. and Mo are the object's length and mass, and Lh and Mh the length and mass of the grasper's hand. However, the generality of the equation was limited by the ad hoc graphical method that defined the lines for grip separation and by the assumption that these lines be negatively sloped and parallel to one another. This article reports an independent test of this relation by the geometrical and statistical categorization of body-scaled invariants for the transition of human grip configurations through support vector machines (SVMs). The SVM analysis confirmed the fit of linear, negatively sloped, and approximately parallel transition boundaries in the scaling of human grip configuration within a single hand. The SVM analysis has provided a theoretical refinement to the scaling model of human grip configurations.     

G*Power 3: A flexible statistical power analysis program for the social,behavioral, and biomedical sciences

G*Power (Erdfelder, Faul, & Buchner, 1996) was designed as a general stand-alone power analysis program for statistical tests commonly used in social and behavioral research. G*Power 3 is a major extension of, and improvement over, the previous versions. It runs on widely used computer platforms (i.e., Windows XP, Windows Vista, and Mac OS X 10.4) and covers many different statistical tests of thet, F, and χ₂ test families. In addition, it includes power analyses forz tests and some exact tests. G*Power 3 provides improved effect size calculators and graphic options, supports both distribution-based and design-based input modes, and offers all types of power analyses in which users might be interested. Like its predecessors, G*Power 3 is free.     

公共卫生和环境论：要把垃圾管理补入环境伦理学史

美国有一个大家所喜爱的、值得注意的有关环境哲学历史根源的记述,它不仅有历史趣闻的内容,而且还有形成当代北美环境哲学之某些关键概念来源的知识。可是,民间的这种对北美环境思想历史起源的知识是不完全的。环境哲学家们一般运用的、以荒野为基础的历史,应该用被忽视的19世纪北美城市垃圾和卫生设施的纪事加以补充。这一补充后的历史改变了北美环境哲学一直犹豫不决的概念领域。这个新领域能更好地应对许多主要的地区和国际环境的挑战。     

Evaluation of narrative abilities in patients suffering from Duchenne Muscular Dystrophy

The present work investigated cognitive, linguistic and narrative abilities in a group of children suffering from Duchenne Muscular Dystrophy, an allelic X-linked recessive disorder caused by mutations in the gene encoding dystrophin. The patients showed mildly reduced IQ with lower Verbal than Performance Intelligence Quotient and were mildly affected in visual attention and short-term memory processing. At the linguistic assessment, neither receptive (word comprehension) nor expressive (naming tasks and fluency) lexical abilities were impaired. However, their narratives were qualitatively inferior with respect to those produced by a group of typically developing children. Their speech samples were characterized by the presence of fewer verbs and complete sentences. It is suggested that the reduced production of complete sentences is due to a selective problem in verb argument structure generation. Since the lack of dystrophin is assumed to produce effects on the maturation of the cerebellum, whose involvement has been recently suggested in verb and syntactic processing, these findings may lend indirect support to the hypothesis of a cerebellar-cortical circuit specialized in verb and sentence production.     

The role of working memory in syntactic ambiguity resolution: a psychometric approach

In 2 studies, the authors used a combination of psychometric and experimental techniques to investigate the effects of domain-general and domain-specific working memory factors on offline decisions concerning attachment of an ambiguous relative clause. Both studies used English and Dutch stimuli presented to English- and Dutch-speaking participants, respectively. In Study 1, readers with low working memory spans were less likely to use recency strategies for disambiguation than were readers with high spans. This finding is inconsistent with predictions of locality- and resource-based accounts of attachment. Psychometric analyses showed that both domain-specific (verbal) and domain-general working memory accounted for the effect. Study 2 found support for the hypothesis that segmentation strategies imposed during silent reading can account for the counterintuitive relationship. Results suggest that readers with low spans have a greater tendency to break up large segments of text because of their limited working memory, leading to high attachment of the ambiguous relative clause.