The role of working memory components and visuospatial abilities in route learning within a virtual environment

An experiment was run to complete our understanding of the involvement of working memory (WM) components in the construction of a spatial model from visual input, considering some of the visuospatial abilities known to modulate performance. In addition, to allow for consideration of the flexibility of the spatial representation, routes in a virtual environment were presented with a route perspective, and tests were presented with route and survey perspectives. The results indicate that the verbal and spatial WM are only involved in the memorisation of certain types of information, and that their involvement depends on the change of perspective necessitated by the task. Thus, even when the learning material and the tests used to assess performance are only visual, a verbal recoding of some information is necessary. Moreover, individual differences modulate the involvement of WM; an individual with higher visuospatial capacities uses more spatial WM than an individual with lower spatial capacities.     

The effect of pointing on spatial working memory in a 3D virtual environment

Pointing to locations can either help or hinder people's ability to recall spatial information. Prior research has focused on two‐dimensional spatial memory and pointing in real world tasks. The effect of pointing on three‐dimensional spatial memory in virtual environments remains unexplored. We examine this effect by comparing participants' recall when they point to and memorize a series of three‐dimensional locations using a gesture interface, and when they only passively view and memorize the spatial array. Thirty‐three participants completed 50 trials in both conditions. The results reveal that pointing has a negative effect on memory in the three‐dimensional virtual environment. These findings held across memory in the x–y plane of the computer screen as well as memory in the virtual third dimension. When they pointed during encoding, participants also responded more slowly, suggesting a higher cognitive load. Thus, active pointing may cause interference when users are simultaneously performing spatial memorization tasks.     

Working memory in wayfinding-a dual task experiment in a virtual city

This study examines the working memory systems involved in human wayfinding. In the learning phase, 24 participants learned two routes in a novel photorealistic virtual environment displayed on a 220° screen while they were disrupted by a visual, a spatial, a verbal, or—in a control group—no secondary task. In the following wayfinding phase, the participants had to find and to "virtually walk" the two routes again. During this wayfinding phase, a number of dependent measures were recorded. This research shows that encoding wayfinding knowledge interfered with the verbal and with the spatial secondary task. These interferences were even stronger than the interference of wayfinding knowledge with the visual secondary task. These findings are consistent with a dual-coding approach of wayfinding knowledge.     

The testing effect in recognition memory: a dual process account

The testing effect, or the finding that taking an initial test improves subsequent memory performance, is a robust and reliable phenomenon--as long as the final test involves recall. Few studies have examined the effects of taking an initial recall test on final recognition performance, and results from these studies are equivocal. In 3 experiments, we attempt to demonstrate that initial testing can change the ways in which later recognition decisions are executed even when no difference can be detected in the recognition hit rates. Specifically, initial testing was shown to enhance later recollection but leave familiarity unchanged. This conclusion emerged from three dependent measures: source memory, exclusion performance, and remember/know judgments.     

Initial validation of a virtual environment for assessment of memory functioning: virtual reality cognitive performance assessment test.

The current project is an initial attempt at validating the Virtual Reality Cognitive Performance Assessment Test (VRCPAT), a virtual environment-based measure of learning and memory. To examine convergent and discriminant validity, a multitrait-multimethod matrix was used in which we hypothesized that the VRCPAT's total learning and memory scores would correlate with other neuropsychological measures involving learning and memory but not with measures involving potential confounds (i.e., executive functions; attention; processing speed; and verbal fluency). Using a sequential hierarchical strategy, each stage of test development did not proceed until specified criteria were met. The 15-minute VRCPAT battery and a 1.5-hour in-person neuropsychological assessment were conducted with a sample of 30 healthy adults, between the ages of 21 and 36, that included equivalent distributions of men and women from ethnically diverse populations. Results supported both convergent and discriminant validity. That is, findings suggest that the VRCPAT measures a capacity that is (a) consistent with that assessed by traditional paper-and-pencil measures involving learning and memory and (b) inconsistent with that assessed by traditional paper-and-pencil measures assessing neurocognitive domains traditionally assumed to be other than learning and memory. We conclude that the VRCPAT is a valid test that provides a unique opportunity to reliably and efficiently study memory function within an ecologically valid environment.     

The specificity of memory enhancement during interaction with a virtual environment

Two experiments investigated differences between active and passive participation in a computer-generated virtual environment in terms of spatial memory, object memory, and object location memory. It was found that active participants, who controlled their movements in the virtual environment using a joystick, recalled the spatial layout of the virtual environment better than passive participants, who merely watched the active participants' progress. Conversely, there were no significant differences between the active and passive participants' recall or recognition of the virtual objects, nor in their recall of the correct locations of objects in the virtual environment. These findings are discussed in terms of subject-performed task research and the specificity of memory enhancement in virtual environments.     

Diazepam and memory: Support for a duplex model of memory

In three experiments, the hypothesis that diazepam (Valium) selectively impairs the transfer of information from short-term to long-term memory was supported by differences between placebo and drugged subjects in effects of item difficulty, serial position (primacy-recency), and list length. In Experiment 1, diazepam reduced recall in the primacy portion of the serial position function, but produced no performance difference in the recency component. Recall decreased in placebo subjects as item difficulty increased, but drugged subjects were relatively uaffected by manipulation of difficulty. In Experiments 2 and 3, subjects treated with diazepam exhibited smaller gains in immediate recall with increasing list length than placebo controls. Retrieval of words learned before drug administration was not impaired by diazepam; in fact, it was significantly enhanced relative to control performance. The results add further support to the distinction between short- and long-term memory.     

A dual memory theory of the testing effect

A new theoretical framework for the testing effect—the finding that retrieval practice is usually more effective for learning than are other strategies—is proposed, the empirically supported tenet of which is that separate memories form as a consequence of study and test events. A simplest case quantitative model is derived from that framework for the case of cued recall. With no free parameters, that model predicts both proportion correct in the test condition and the magnitude of the testing effect across 10 experiments conducted in our laboratory, experiments that varied with respect to material type, retention interval, and performance in the restudy condition. The model also provides the first quantitative accounts of (a) the testing effect as a function of performance in the restudy condition, (b) the upper bound magnitude of the testing effect, (c) the effect of correct answer feedback, (d) the testing effect as a function of retention interval for the cases of feedback and no feedback, and (e) the effect of prior learning method on subsequent learning through testing. Candidate accounts of several other core phenomena in the literature, including test-potentiated learning, recognition versus cued recall training effects, cued versus free recall final test effects, and other select transfer effects, are also proposed. Future prospects and relations to other theories are discussed.     

A dual task response modality effect: Support for multiprocessor models of attention

In Experiment I two groups of 11 men performed a continuous visual input/manual output task simultaneously with a two-choice tone identification task. One group responded vocally to the tones; one group responded with the hand not involved in the continuous tracking task. In either perceptual or stimulus uncertainty terms the two combinations were identical; the only difference between them was the modality of the two-choice responses. The continuous task was performed significantly worse when the two-choice responses were manual. The probability of response production on the continuous task was affected by the production of manual responses but not by the production of vocal responses. It was concluded that although the two manual responses were produced by a single limited capacity process, the manual and vocal responses were produced by independent processes. In Experiment II the same manual tracking task was combined with a mental arithmetic task at two levels of difficulty. Tracking performance was independent of the difficulty of the arithmetic task. These results support a multi-processor approach to attention as opposed to single channel models. Results of dual task studies which have used only one pair of response modalities are re-examined in the light of the response modality effect found in Experiment I.     

Linda问题的表象-命题双表征解释视角探究

本文首先提出了Linda问题的表象-命题双表征这一新的解释视角。该视角认为,Linda问题基于表象表征和命题表征可以有两种不同的解读与表征方式;而不同的被试在Linda问题上可能分别采取了上述表征方式之一;但由于Linda问题的特殊性,大多数被试采用了表象表征;大多数被试的这一表征取向则可能是所谓谬误判断出现的原因。本文通过4项研究,让被试在基于表象表征设计的转述版本与基于命题表征设计的转述版间选择接近自身理解的版本;并考察了将Linda问题修改成更符合命题表征的数学化表达形式能否降低所谓谬误水平;还考察了增加促使被试运用命题表征的排序项"Linda是全人类中的一员"能否降低所谓谬误水平。结果显示,在转述版本选择上,大多数被试选择了基于表象表征设计的版本;而上文所指的两个修正版Linda问题则都降低了被试的所谓谬误水平。这些结果支持了本文所提的视角。     

Nature of the representation for picture-recognition memory

When distracting pictures are randomly selected from the same pool of pictures as the target pictures, performance with large numbers of pictures (1,000) is much poorer than has previously been reported. Further, performance drops quite substantially after 1 wk., a finding that differs from the conclusion that picture memory is relatively stable over time. Under conditions where the distractors were selected to reduce similarity between targets and distracting pictures, performance approximated levels previously reported in the literature. The results of the experiments seem to demand some type of categorization model of picture-recognition memory.     

Narrowing the Creativity Gap: The Moderating Effects of Perceived Support for Creativity

This article examines the role of 3 types of perceived support for creativity in moderating the relation between creative self-efficacy and self-perceived creativity. The findings suggest significant interaction effects for perceived work-group support and supervisor support, but not for perceived organizational support. This study is among the first to (a) examine the importance of perceived support for creativity in unlocking creative potential and increasing creativity in organizations and (b) use interaction terms in structural equation modeling (SEM) to investigate moderator effects in an applied research setting. These results imply that organizational interventions focused on training supervisors and work-group members to support creativity in the workplace may be more effective than broader and less focused interventions at the organizational level.     

Perceptual interactions in a minimalist virtual environment

How in real-life or through the use of technical devices can we recognize the presence of other persons and under what conditions can we differentiate them from objects? In order to approach this question, in the study reported here we explored the most basic conditions necessary for participants to recognize the presence of another person during a perceptual interaction. We created a mini-network of two minimalist devices and investigated whether participants were able to differentiate the perception of another person from the perception of a fixed and a mobile object even when the pattern of sensory stimulation was reduced to a bare minimum. We show that participants can recognize when the all-or-none tactile stimulation they experienced was attributable to an encounter with the other participant's avatar or the mobile object rather than with a fixed object. Participants were also able to establish different strategies in order to favor the situations of mutual perception. Thus, in the minimalist conditions of our experiment, the perception of another intentional subject was not based purely on any particular shape or objective trajectories of displacement; it was also based on properties that are intrinsic to the joint perceptual activity itself.     

Velocity constancy in a virtual reality environment

During everyday life the brain is continuously integrating multiple perceptual cues in order to allow us to make decisions and to guide our actions. In this study we have used a simulated (virtual reality--VR) visual environment to investigate how cues to speed judgments are integrated. There are two sources that could be used to provide signals for velocity constancy: temporal-frequency or distance cues. However, evidence from most psychophysical studies favours temporal-frequency cues. Here we report that two depth cues that provide a relative object--object distance--disparity and motion parallax--can provide a significant input to velocity-constancy judgments, particularly when combined. This result indicates that the second mechanism can also play a significant role in generating velocity constancy. Furthermore, we show that cognitive factors, such as familiar size, can influence the perception of object speed. The results suggest that both low-level cues to spatiotemporal structure and depth, and high-level cues, such as object familiarity, are integrated by the brain during velocity estimation in real-world viewing.     

Human foraging behavior in a virtual environment

We have developed an experimental platform that allows a large number of human participants to interact in real time within a common virtual world. Within this environment, human participants foraged for resources distributed in two spatially separated pools. In addition to varying the relative replenishment rate for the two pools (50-50, 65-35, or 80-20), we manipulated whether the participants could see each other and the entire resource distribution or had their vision restricted to resources at their own location. Two empirical deviations from an optimal distribution of the participants were found. First, the participants were more scattered within a resource pool than the resources were themselves. Second, there was systematic underutilization of the richer pool. For example, the participants distributed themselves 73% and 27% to resource pools that had replenishment rates of 80% and 20%, respectively. In addition, there were oscillations in the harvesting rate of the pools across time, revealed by a Fourier analysis with prominent power near 50 sec per cycle. The suboptimalities and oscillations were more apparent when the locations of the participants and the food were not visible. Individual participant knowledge thus affects the efficiency with which a population of participants harvests resources.     

Effect of viewing angle on arm reaching while standing in a virtual environment: Potential for virtual rehabilitation

Functional arm movements, such as reaching while standing, are planned and executed according to our perception of body position in space and are relative to environmental objects. The angle under which the environment is observed is one component used in creating this perception. This suggests that manipulation of viewing angle may modulate whole body movement to affect performance. We tested this by comparing its effect on reaching in a virtually generated environment. Eleven young healthy individuals performed forward and lateral reaches in the virtual environment, presented on a flat screen in third-person perspective. Participants saw a computer-generated model (avatar) of themselves standing in a courtyard facing a semi-circular hedge with flowers. The image was presented in five different viewing angles ranging from seeing the avatar from behind (0°), to viewing from overhead (90°). Participants attempted to touch the furthest flower possible without losing balance or stepping. Kinematic data were collected to analyze endpoint displacement, arm-postural coordination and center of mass (COM) displacement. Results showed that reach distance was greatest with angular perspectives of approximately 45-77.5°, which are larger than those used in analogous real world situations. Larger reaches were characterized by increased involvement of leg and trunk body segments, altered inter-segmental coordination, and decreased inter-segmental movement time lag. Thus a viewing angle can be a critical visuomotor variable modulating motor coordination of the whole body and related functional performance. These results can be used in designing virtual reality games, in ergonomic design, teleoperation training, and in designing virtual rehabilitation programs that re-train functional movement in vulnerable individuals.     

Verb semantic structures in memory for sentences: Evidence for componential representation

This research contrasts two hypotheses concerning componential storage of meaning. The Complexity Hypothesis assumed by Fodor (The language of thought, NY: Crowell, 1975), Kintsch (The representation of meaning in memory, Hillsdale, NJ: Erlbaum, 1974), and Thorndyke (Conceptual complexity and imagery in comprehension and memory. Journal of Verbal Learning and Verbal Behavior, 1975, 14, 359–369) states that a word with many semantic components will require more processing resources, comprehension time, and long-term memory space than a word with few components, and thus will interfere more with memory for surrounding words. This memory prediction was tested against an alternative prediction based on connectivity. The Connectivity Hypothesis views verb semantic structures as frames for sentence representation and states that memory strength between two nouns in a sentence increases with the number of underlying verb subpredicates that connect the nouns. Thus, the Complexity Hypothesis predicts that a verb with many subpredicates will lead to poorer memory strength between the surrounding nouns than a verb with few subpredicates, while the Connectivity Hypothesis predicts that verbs with many subpredicates will lead to greater memory strength between nouns in cases when the additional subpredicates provide semantic connections between the nouns.In three experiments, subjects recalled subject-verb-object sentences, given subject nouns as cues. General verbs, with relatively few subpredicates, were compared with more specific verbs whose additional subpredicates either did or did not provide additional connections between the surrounding nouns. The level of recall of the object noun, given the subject noun as cue, was predicted by the relative number of connecting subpredicates in the verb, but not by the relative number of subpredicates. This finding supports the Connectivity Hypothesis over the Complexity Hypothesis. These results are interpreted in terms of a model in which the verb conveys a structured set of subpredicates that provides a connective framework for sentence memory.