Developmental continuity in the processes that underlie spatial recall

This study investigated whether children's spatial recall performance shows three separable characteristics: (1) biases away from symmetry axes (geometric effects); (2) systematic drift over delays; and (3) biases toward the exemplar distribution experienced in the task (experience-dependent effects). In Experiment 1, the location of one target within each geometric category was varied. Children's responses showed biases away from a midline axis that increased over delays. In Experiment 2, multiple targets were placed within each category at the same locations used in Experiment 1. After removing geometric effects, 6-year-olds'--but not 11-year-olds'--responses were biased toward the average remembered location over learning. In Experiment 3, children responded to one target more frequently than the others. Both 6- and 11-year-olds showed biases toward the most frequent target over learning. These results provide a bridge between the performance of younger children and adults, demonstrating continuity in the processes that underlie spatial memory abilities across development.     

Multi-objective combinatorial optimization problems: A survey

In the last 20 years many multi-objective linear programming (MOLP) methods with continuous variables have been developed. However, in many real-world applications discrete variables must be introduced. It is well known that MOLP problems with discrete variables can have special difficulties and so cannot be solved by simply combining discrete programming methods and multi-objective programming methods. The present paper is intended to review the existing literature on multi-objective combinatorial optimization (MOCO) problems. Various classical combinatorial problems are examined in a multi-criteria framework. Some conclusions are drawn and directions for future research are suggested.     

Testing the exclusivity effect in location memory

There is growing literature exploring the possibility of parallel retrieval of location memories, although this literature focuses primarily on the speed of retrieval with little attention to the accuracy of location memory recall. Baguley, Lansdale, Lines, and Parkin (2006) found that when a person has two or more memories for an object's location, their recall accuracy suggests that only one representation can be retrieved at a time (exclusivity). This finding is counterintuitive given evidence of non-exclusive recall in the wider memory literature. The current experiment explored the exclusivity effect further and aimed to promote an alternative outcome (i.e., independence or superadditivity) by encouraging the participants to combine multiple representations of space at encoding or retrieval. This was encouraged by using anchor (points of reference) labels that could be combined to form a single strongly associated combination. It was hypothesised that the ability to combine the anchor labels would allow the two representations to be retrieved concurrently, generating higher levels of recall accuracy. The results demonstrate further support for the exclusivity hypothesis, showing no significant improvement in recall accuracy when there are multiple representations of a target object's location as compared to a single representation.     

三字字谜顿悟的时频特征与源定位

运用事件相关电位(ERPs)技术,采用猜谜任务范式,从字谜问题解决中谜底“催化”所诱发顿悟的时间过程和源定位两方面来探讨顿悟的认知神经机制。脑电时程分析显示,在320-550ms内,“有顿悟”较“无顿悟”的ERP波形有一个更大的负向偏移,且在“有顿悟-无顿悟”差异波中,该负成分的潜伏期约为380ms,差异波的脑电峰值锁定在Cz点。EEG时频则显示N380主要表现为减弱的高频gamma波和beta波的频谱特征。独立成分溯源结果显示,N380存在四个独立源,主要分布在右侧额中回、左侧顶下小叶、右侧颞上回和右侧额下回。这些结果表明,三字字谜顿悟的N380就是N400,且主要负责三字顿悟字谜外显含义到内隐隐喻意义的表征转换加工。     

Location representation in enclosed spaces: What types of information afford young children an advantage?

It has been suggested that young children can only reorient, locating a target object, when the geometry of an enclosed space provides distinctive shape information [e.g., Hermer, L., & Spelke, E. (1994). A geometric process for spatial reorientation in young children. Nature, 370, 57-59]. Recently, however, young children were shown to specify location in a square-shaped space, where geometry is uninformative, so long as scale-like information was available on the walls of the space [Huttenlocher, J., & Lourenco, S. F. (2007a). Coding location in enclosed spaces: Is geometry the principle? Developmental Science, 10, 741-746]. Here we build on this work by examining more closely what types of cues afford 18- to 24-month-olds an advantage in locating a target object following disorientation. Their performance was assessed when linear scale-like information was presented either in isolation or in composite form. It was found that, even in isolation, young children searched at the appropriate locations, with added benefit when presented as a composite. We suggest that linear scale-like dimensions, especially when available in composite form, play a critical role in supporting location representation in young children.     

Defining ‚exdurance’

On stage theory, ordinary continuants are instantaneous stages which persist by exduring—by bearing temporal counterpart relations to other such stages. Exduring objects lack temporal extension and there is a sense in which they are wholly present at multiple instants. How then is exdurance different from endurance? I offer a definition of ?exdurance’ that clearly sets it apart from other modes of persistence.     

Memory development in the second year: for events or locations?

We employed an object-placement/object-removal design, inspired by recent work on 'episodic-like' memory in scrub jays (Clayton, N. S., & Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature, 395, 272-274), to examine the possibility that children in the second year of life have event-based memories. In one task, a successful search could have been due to the recall of an object-removal event. In the second task, a successful search could only have been caused by recall of where objects were located. Success was general in the oldest group of children (21-25 months), while performance was broadly similar on the two tasks. The parsimonious interpretation of this outcome is that the first task was performed by location memory, not by event memory. We place these data in the context of object permanence development.     

Experiencing nearby locations together in time: the role of spatiotemporal contiguity in children's memory for location

Three studies investigated how experiencing nearby locations together in time influences memory for location. Seven-, 9-, and 11-year-old children and adults learned 20 object locations in a small-scale space. The space was divided into regions by lines or walls. In Study 1, participants learned the locations either region by region or in a random order. Following learning, participants replaced the objects without the aid of the dots marking the locations and the boundaries subdividing the space. They replaced the objects in any order they chose. After experiencing the locations in random orders during learning, only adults underestimated distances between locations belonging to the same group (i.e., region). Conversely, 9- and 11-year-old children and adults who had experienced the locations region by region during learning underestimated these distances. These findings suggest that experiencing nearby locations together in time increases the weight children assign to categorical information in their estimates of location. Results from Studies 2 and 3 in which participants learned the locations region by region and then replaced the objects region by region (Study 2) or in a random order (Study 3) were similar, highlighting the importance of spatiotemporal cues in memory for location. (c) 2002 Elsevier Science (USA).     

Seeing Like a Geologist: Bayesian Use of Expert Categories in Location Memory

Memory for spatial location is typically biased, with errors trending toward the center of a surrounding region. According to the category adjustment model (CAM), this bias reflects the optimal, Bayesian combination of fine‐grained and categorical representations of a location. However, there is disagreement about whether categories are malleable. For instance, can categories be redefined based on expert‐level conceptual knowledge? Furthermore, if expert knowledge is used, does it dominate other information sources, or is it used adaptively so as to minimize overall error, as predicted by a Bayesian framework? We address these questions using images of geological interest. The participants were experts in structural geology, organic chemistry, or English literature. Our data indicate that expertise‐based categories influence estimates of location memory—particularly when these categories better constrain errors than alternative (“novice”) categories. Results are discussed with respect to the CAM.     

The influence of a pedestrian countdown display on pedestrian behavior at signalized pedestrian crossings

Pedestrian behavior has been a subject of surveys carried out at two signalized pedestrian crossings, in the city of Doboj (BIH, Republic of Srpska). The analysis is made on the basis of video recordings, and includes behavior at pedestrian crossings, in various conditions (two locations, different vehicle flows, with or without a countdown display). The analysis also includes the distribution of illegal crossings (at the pedestrian red light) of different categories of pedestrians (gender, age), before and after the installation of a pedestrian countdown display, at two different pedestrian crossings. The results of the study have shown that a countdown display reduces statistically significantly the total number of violators, regardless of its location and traffic flow. However, this reduction is not the same at various categories of pedestrians (male, female, elderly, young people). The influence of the display has been particularly dominant at the pedestrian crossing located outside the centre of the city, with the smaller intensity of traffic. Children pedestrians do not accept the behavior in accordance with the countdown display in case of a reduced intensity of traffic, at a pedestrian crossing located in the backstreet. A countdown display does not statistically significantly change the distribution form of the number of offences during the red light for pedestrians, regardless of the pedestrian environment. However, there is a statistically significant difference in certain intervals (during the first and last 4 s) in the total distribution, as well as in the categories (female pedestrians, children). A countdown display does not reduce the overall number of “slow” pedestrians, but the impact on certain categories of “slow” pedestrians (gender/children), as well as on pedestrian violators, per age categories, varies depending on the location and traffic flow at an intersection.