Failure to exploit learned spatial value information during visual search

ABSTRACT

In recent years there has been rapid proliferation of studies demonstrating how reward learning guides visual search. However, most of these studies have focused on feature-based reward, and there has been scant evidence supporting the learning of space-based reward. We raise the possibility that the visual search apparatus is impenetrable to spatial value contingencies, even when such contingencies are learned and represented online in a separate knowledge domain. In three experiments, we interleaved a visual choice task with a visual search task in which one display quadrant produced greater monetary rewards than the remaining quadrants. We found that participants consistently exploited this spatial value contingency during the choice task but not during the search task – even when these tasks were interleaved within the same trials and when rewards were contingent on response speed. These results suggest that the expression of spatial value information is task specific and that the visual search apparatus could be impenetrable to spatial reward information. Such findings are consistent with an evolutionary framework in which the search apparatus has little to gain from spatial value information in most real world situations.     

The Influence of Reduced Visual Acuity on Age-Related Decline in Spatial Working Memory: An Investigation

ABSTRACT

To investigate the relationship between visual acuity and cognitive function with aging, we compared low-vision and normally-sighted young and elderly individuals on a spatial working memory (WM) task. The task required subjects to memorise target locations on different matrices after perceiving them visually or haptically. The haptic modality was included as a control to look at the effect of aging on memory without the confounding effect of visual deficit. Overall, age and visual status did not interact to affect WM accuracy, suggesting that age does not exaggerate the effects of visual deprivation. Young participants performed better than the elderly only when the task required more operational processes (i.e., integration of information). Sighted participants outperformed the visually impaired regardless of testing modality suggesting that the effect of the visual deficit is not confined to only the most peripheral levels of information processing. These findings suggest that vision, being the primary sensory modality, tends to shape the general supramodal mechanisms of memory.     

No Time of Day Modulation or Time Stamp on Multiple Memory Tasks in Rats

Various demonstrations of “time stamp” effects in the animal learning literature have reinforced the idea that circadian information is encoded as part of a combined internal/external representation of context and that this contextual information is utilized for complex retrieval processes supporting memory. The goal of the present series of experiments is to assess this idea by manipulating training/testing circadian times on a battery of learning and memory tasks commonly used in the rodent. The data obtained from five experiments using four different learning and memory paradigms provide no evidence for “time stamp” effects on place memory, context memory (aversive or appetitive), or S-R habit learning.     

小学生视觉-空间表征类型和数学问题解决的研究

本研究考察并比较了四至六年级儿童的视觉－空间表征策略、数学问题解决和空间视觉化能力。结果表明：五、六年级儿童的解题正确率、使用图式表征策略的程度显著高于四年级儿童;使用图像表征策略的程度各年级无显著差异。将数学问题分成三个难度等级,发现年级差异主要表现在难度等级1的题目上。另外,六年级儿童的空间视觉化能力显著高于四年级儿童。     

Individual Differences in Spatial Memory and Striatal ChAT Activity among Young and Aged Rats

Individual differences in spatial memory among young and aged rats were assessed using memory tasks related to integrity of the hippocampus and the neostriatum. Relationships were then examined between measures of spatial memory and regional choline acetyltransferase (ChAT) activity, a marker for cholinergic integrity. Twenty-four-month-old Long-Evans rats were impaired in comparisons with 6-month-old rats on measures of place learning, working memory, reference memory, and perseveration in water-maze tasks. Aged rats that were impaired on one measure of memory, however, were not necessarily impaired on other measures. ChAT activity in the ventromedial and dorsolateral neostriatum of aged rats was significantly reduced in comparisons with young rats whereas no difference was found in the hippocampus. Aged rats with the most ChAT activity in the anterior ventromedial neostriatum performed best on the place-learning and reference memory tasks but also made the most perseverative errors on the working memory task. In addition, young and aged rats with the most ChAT activity in the anterior dorsolateral neostriatum were those with the least accurate working memory. No relationships were found between ChAT activity in the hippocampus and spatial memory. Thus age-related memory impairment has components that can be segregated by measuring relationships between cholinergic integrity in subregions of the anterior neostriatum and memory tasks with different strategic requirements.     

分散空间注意条件下客体特征一致性对视觉特征错觉性结合的影响

本研究通过设置对空间注意资源的分配实施强行操作的情形下,探讨了主、次作业客体形状一致性和次作业客体间距对乏空间注意区次作业客体颜色、形状特征的检测及对特征错觉性结合的影响。实验结果表明：（１）分散空间注意使次作业区域注意减弱,对客体及其颜色和形状特征的识别均产生明显影响．而且对形状的影响又大于颜色;（２）特征错觉性结合率,主、次作业客体形状一致时比客体形状不一致时明显增大;（３）次作业客体间距对特征错觉性结合率无明显影响,但客体形状一致性和客体间距之间存在明显交互作用．     

幼儿二维心理旋转能力发展的研究

在以旋转的米老鼠图形作为测试项目,对每半岁为一个年龄段共１３３名３．５一６．５岁的幼儿进行心理旋转的实验研究中发现,幼儿在４岁时已经开始建立心理旋转能力．其发展特征呈连续性;男女幼儿间有一定的性别差异存在,但统计结果提示无显著性意义;男女幼儿在５－６岁间都发现有一个负增长阶段,其原因不明。     

Walking through doorways causes forgetting: environmental effects

Previous work has shown a decline in memory for objects carried through a doorway versus across a room. The aim of the current study is to extend this work to understand how variations in perceptual experience during these event shifts influence this finding. First a change in procedure to reduce memory load to a single item was assessed. Next we explored whether performance is influenced by spatial distance versus spatial categories, the ability to perceptually preview the next location, and changes in the colour and texture of the walls. The location updating effect was consistently observed for all manipulations, suggesting that such event transformations have a robust influence on human memory. This suggests that event cognition is driven more by the use of perceptual information to infer or impose a categorical shift from one event to another rather than by the nature of perceptual information available at the time.     

Integration of spatial information across vision and language

Three experiments investigated whether spatial information acquired from vision and language is maintained in distinct spatial representations on the basis of the input modality. Participants studied a visual and a verbal layout of objects at different times from either the same (Experiments 1 and 2) or different learning perspectives (Experiment 3) and then carried out a series of pointing judgments involving objects from the same or different layouts. Results from Experiments 1 and 2 indicated that participants pointed equally fast on within- and between-layout trials; coupled with verbal reports from participants, this result suggests that they integrated all locations in a single spatial representation during encoding. However, when learning took place from different perspectives in Experiment 3, participants were faster to respond to within- than between-layout trials and indicated that they kept separate representations during learning. Results are compared to those from similar studies that involved layouts learned from perception only.