One-trial associative memory: comparison of food-storing and nonstoring species of birds

Experiment 1 compared food-storing marsh tits and nonstoring blue tits, and Experiment 2 compared food-storing jays and nonstoring jackdaws, in a one-trial associative memory task, Birds obtained a reward by returning to the site where they had eaten part of the reward 30 min earlier. In “visible” versions, the reward was visible in Phase 1 but hidden in Phase 2 so that the bird had to search for it; in “hidden” versions, the reward was hidden in both phases. No species differences were found in performance in the visible version. However, in the hidden version, the 2 storers preferentially returned to rewarded sites, whereas nonstorers preferentially returned to sites that had been visited in Phase 1, irrespective of whether or not they contained a reward. This suggests that storers differ from nonstorers in the way they discriminate between remembered events.     

Overshadowing of geometric cues by a beacon in a spatial navigation task

In three experiments, we examined whether overshadowing of geometric cues by a discrete landmark (beacon) is due to the relative saliences of the cues. Using a virtual water maze task, human participants were required to locate a platform marked by a beacon in a distinctively shaped pool. In Experiment 1, the beacon overshadowed geometric cues in a trapezium, but not in an isosceles triangle. The longer escape latencies during acquisition in the trapezium control group with no beacon suggest that the geometric cues in the trapezium were less salient than those in the triangle. In Experiment 2, we evaluated whether generalization decrement, caused by the removal of the beacon at test, could account for overshadowing. An additional beacon was placed in an alternative corner. For the control groups, the beacons were identical; for the overshadow groups, they were visually unique. Overshadowing was again found in the trapezium. In Experiment 3, we tested whether the absence of overshadowing in the triangle was due to the geometric cues being more salient than the beacon. Following training, the beacon was relocated to a different corner. Participants approached the beacon rather than the trained platform corner, suggesting that the beacon was more salient. These results suggest that associative processes do not fully explain cue competition in the spatial domain.     

A comparison between elemental and compound training of cues in retrospective revaluation

Associative learning theories assume that cue interaction and, specifically, retrospective revaluation occur only when the target cue is previously trained in compound with the to-be-revalued cue. However, there are recent demonstrations of retrospective revaluation in the absence of compound training (e.g., Matute &; Pineño, 1998a, 1998b). Nevertheless, it seems reasonable to assume that cue interaction should be stronger when the cues are trained together than when they are trained apart. In two experiments with humans, we directly compared compound and elemental training of cues. The results showed that retrospective revaluation in the elemental condition can be as strong as and, sometimes, stronger than that in the compound condition. This suggests that within-compound associations are not necessary for retrospective revaluation to occur and that these effects can possibly be best understood in the framework of general interference theory.     

A comparison of learned aversions to gustatory and exteroceptive cues in rats

The experiment provides a direct comparison of the ability of subjects (rats) to associate gustatory and exteroceptive stimuli with illness. Previous experiments which have made similar comparisons between gustatory and exteroceptive cues have suffered from certain methodological problems involving stimulus control and compounding. The present experiment utilized a between-subjects design wherein half of the subjects had an auditory cue associated with poisoning and half had a taste cue. In both cases, the other cue was present, but was not predictive of poisoning, The auditory cue, like the taste cue, occurred only during drinking. This comparison was made in both an immediate and a delayed poisoning situation. The experiment found that while subjects were able to quickly associate a taste cue with illness, they were unable to form a similar association between poisoning and the exteroceptive stimulus. Results also showed that subjects will fail to acquire a taste aversion to a novel and salient gustatory cue when that cue is followed by illness only 50% of the time. This latter effect was more pronounced in the delayed poisoning situation.     

In the dark II: spatial choice when access to extrinsic spatial cues is eliminated

Rats were tested in a specially constructed radial-arm maze that eliminated access to extramaze visual cues and allowed any effects of intramaze cues to be controlled. Despite this, choice accuracy was controlled by the spatial location of previously visited arms. Part of this control was attributed to vestibular or kinesthetic cues. This conclusion was corroborated by the finding that when explicit visual cues were moved from their standard (trained) spatial locations to novel locations, control of spatial choices was completely disrupted. The latter finding indicates that cues intrinsic to the rat (kinesthetic or vestibular information) and cues extrinsic to the rat (visual stimuli) operate in an integrated fashion.     

Visualizing spatial tasks: A comparison of computer graphic and full-band video displays

Three spatial tasks were created in two forms, as video and as computer graphics. Both forms of each task were presented to third graders, middle schoolers, and adults preferred working with the video but were more accurate working with computer graphics. Third graders preferred the computer but were equally successful working with both displays. The study suggests that the expectations with which students approach an instructional technology may determine the effectiveness of that technology more than characteristics of the technology in question.     

No evidence for overshadowing or facilitation of spatial pattern learning by visual cues

Two experiments were conducted to examine the effects of redundant and relevant visual cues on spatial pattern learning. Rats searched for hidden food items on the tops of poles that formed a square (Experiment 1) or a checkerboard (Experiment 2) pattern. The experimental groups were trained with visual cues that specified the locations of the baited poles. All groups were tested without visual cues so that any overshadowing or facilitation of spatial pattern learning by visual cues could be detected. Spatial choices were controlled by the spatial pattern and by the visual cues in both experiments. However, there was no evidence of overshadowing or facilitation of spatial pattern learning by visual cues in either experiment. The results are consistent with the idea that the representation of the spatial pattern that guides choices is not controlled by the same learning processes as those that produce associations between visual cues and food locations.     

An eye tracking comparison of external pointing cues and internal continuous cues in learning with complex animations

Two experiments used eye tracking to investigate a novel cueing approach for directing learner attention to low salience, high relevance aspects of a complex animation. In the first experiment, comprehension of a piano mechanism animation containing spreading-colour cues was compared with comprehension obtained with arrow cues or no cues. Eye tracking data revealed differences in learner attention patterns between the different experimental conditions. The second experiment used eye tracking with synchronized and non-synchronized cues to investigate the role of dynamic direction of attention in cueing effectiveness. Results of Experiment 1 showed that spreading-colour cues resulted in better targeting of attention to thematically relevant aspects and in higher comprehension scores than arrow cues or no cues. For Experiment 2, superior comprehension after the synchronized version together with eye tracking data indicated that cue effectiveness depended on attention direction being spatially and temporally coordinated with onsets of animation events having high thematic relevance to the learning task. The findings suggest the importance of perceptual cues and bottom-up processing.     

Memory for a stimulus versus anticipation of a response: Contrasting effects of proactive interference in two delayed comparison tasks

Pigeons were trained to perform two delayed comparison tasks that differed only in the temporal placement of the retention interval relative to the sample and comparison stimuli. In one task (conditional delayed response—CDR), the subject could determine the correct response prior to the retention interval. In the second task (delayed conditional response—DCR), the subject was required to compare stimuli presented before and after the retention interval. Although overt mediational responding was not observed in the CDR condition, retention was, nevertheless, greater than in the DCR condition. Furthermore, this difference was amplified at short intertrial intervals. Finally, retention in the DCR, but not the CDR, condition was disrupted by proactive interference (PI) from previous sample stimuli. The results suggest that memory is less closely tied to the sample stimulus when the stimuli necessary to determine the correct response are presented prior to the retention interval (CDR and other delayed response tasks) than when the subject must compare stimuli across the retention interval (DCR, or delayed matching-to-sample, tasks). This difference may lead directly, or indirectly through an interaction with PI, to task differences in retention.     

In the dark: Spatial choice when access to spatial cues is restricted

The cognitive mechanisms involved in spatial choice when access to visual cues is restricted were examined in three experiments using male rats. A specially constructed radial-arm maze was used, in which extramaze visual cues could not be perceived from the central arena, but could be perceived from the maze arms. Choices were very accurate when the maze was not rotated during each trial, but inaccurate when the maze was rotated. This suggests that intramaze cues were involved in the control of choices. However, the data clearly showed that choices were not simply controlled by intramaze cues. Rather, control by intramaze cues interacted in a more complex manner with representations of the spatial locations of goals. Such spatial representations were involved in the control of choice despite the absence of visual spatial cues at the time choices were made.     

Comparing spatial memory in two species of tit: Recalling a single positive location

The performance of a food-storing species, the marsh tit(Parus palustris), was compared with that of a nonstorer, the blue tit(P. caeruleus), in a spatial memory task in which birds had to return to a site where they had previously been allowed to eat part of a piece of peanut. No differences were found between species’ overall performance, but increasing retention interval from 1 min to 24 h brought about a decrease in performance. The results are discussed in relationship to the hypothesis that food-storing birds have a specialized spatial memory capacity.     

Language and Memory Development in Children with Down Syndrome at Mainstream Schools and Special Schools: A comparison

Increasingly, children with Down syndrome are receiving their education in mainstream schools but little research has investigated whether these placements may influence language and memory development. The present study compared 22 children with Down syndrome in mainstream school placements matched for chronological age with 22 children attending special schools in a different LEA where mainstream placements were rare. The children were assessed to obtain measures of the following language and memory abilities: receptive vocabulary; grammar comprehension; sentence repetition; digit span; face recognition; and memory for hand movements. Children in mainstream placements achieved significantly higher scores for vocabulary, grammar and digit span measures, but not for non-language based memory measures. More importantly, even after controlling for age and receptive vocabulary, grammar understanding and digit spans were significantly greater for the mainstream children.     

The learned function of food-deprivation cues: A role for conditioned modulation

Rats trained in one context to use stimuli arising from food deprivation as discriminative signals for shock were tested in other contexts to assess the basis of conditioned responding (i.e., freezing or behavioral immobility). In Experiment 1, discriminative control by 24-h food-deprivation cues failed to promote transfer responding in a test context that had no association with shock. This indicated that food deprivation cues had little direct excitatory power. However, transfer of behavioral control by 24-h food-deprivation cues was obtained in a context paired with shock only when the rats were 19 h water deprived. This finding agrees with the idea that food-deprivation cues become conditioned modulators of the capacity of external stimuli to activate their association with an unconditioned stimulus. In Experiment 2, rats trained to use 24-h food-deprivation cues as signals for shock exhibited significantly greater transfer performance when the transfer context had undergone partial extinction relative to when the transfer context had undergone only simple excitatory training. This finding with deprivation cues and transfer contexts (1) paralleled earlier results obtained with discrete (auditory and visual) conditioned modulators and transfer targets, and (2) posed difficulties for associative summation and generalization interpretations of transfer performance.     

Social working memory: Memory for another rat's spatial choices can increase or decrease choice tendencies

In two experiments using a radial-arm maze, pairs of rats made choices among eight maze locations, each containing a large quantity of one of two food types. The choices made by 1 rat affected the choices made by the other rat. Under most conditions, visits by 1 rat increased the tendency of the other rat to subsequently choose that maze location. However, the effect depended on the quality of the food available in a particular location. When it was possible for the rats to observe each other on the maze arms and a rat had experienced that a location contained the less preferred food type, a previous visit to that location by the foraging partner decreased the tendency to visit that location. These effects are attributed to working memory for the spatial choices of another rat, and they indicate that memory produced by a rat’s own visit to a maze location is integrated with memory for the behavior of another rat to determine spatial choice     

Learning to recalibrate the role of dead reckoning and visual cues in spatial navigation

In Experiment 1, hamsters started from their permanent home at the periphery of a circular arena and headed to a food source at the center. They then returned, fully laden with food, along a direct path to their home. On control trials, in which no manipulation takes place, visual cues outside the arena and dead reckoning (i.e., updated internal references generated during the outward journey to the food source) controlled the return journey. On experimental trials, the arena, with the hamster in its nest, was rotated by 90°, putting dead reckoning at variance with the distal visual environment. The animals were rewarded for going with dead reckoning. At first, they favored the distal cues, but later most of the subjects switched to using dead reckoning. Thus, hamsters are flexible enough to recalibrate the relative weight that they normally attribute to different sets of spatial cues. In Experiment 2, the reliance on dead-reckoning was greatly enhanced when a cue card at the nest entrance was rotated along with the arena, pitting one proximal cue plus dead reckoning against distal cues. Hence, dead reckoning and external cues seem to reinforce each other through their mutual correlation.     

作为记忆形象的多余人——俄罗斯文学与文化记忆

多余人是俄罗斯文学中知识分子的典型形象。从记忆形象来思考多余人,无疑会加深对俄罗斯文学长廊中多余人形象的认识。俄罗斯文学中多余人形象的出现总是与俄罗斯社会变革和文化转型的预兆紧密相关。俄罗斯知识分子中大批对暗潮涌动的时代风云先知先觉而又无能力成为弄潮儿之人,使奥涅金和利扎文等成为一代代多余人,而且一代比一代更具悲剧性和荒诞性。     

浅谈石油制品进销存综合管理的实现

本介绍一个石油制品进销存综合管理系统的具体实现方案。该系统包括三个子系统：加油监控子系统、液位遥测监视子系统和业务管理子系统。加油监控子系统完成电脑加油机／付油控制仪的监控；液位遥测监视子系统完成储油罐的液住、界面和温度测量，通过容积表换算成液体容积和质量；业务管理子系统通过对存储的加油数据和储油容积、质量数据进行处理，实现加油站／油库的日常管理功能。     

Children’s Memory: A Primer for Understanding Behavior

This paper provides the opportunity to understand children’s behavior from a memory viewpoint. For the last three decades, cognitive developmentalists have been asking the question, “what develops in children’s memory?” Four answers to this question are presented, complete with explanations, examples, and possible applications where appropriate. The purpose of the paper is to provide early childhood educators and other practitioners who work with children a different lens through which to view children’s behavior. The memory view is compatible with current best practices in early childhood education, and may provide practitioners an additional viewpoint from which to draw when implementing developmentally appropriate practice.