Differences in spatial knowledge acquired from maps and navigation

Models of the spatial knowledge people acquire from maps and navigation and the procedures required for spatial judgments using this knowledge are proposed. From a map, people acquire survey knowledge encoding global spatial relations. This knowledge resides in memory in images that can be scanned and measured like a physical map. From navigation, people acquire procedural knowledge of the routes connecting diverse locations. People combine mental simulation of travel through the environment and informal algebra to compute spatial judgments. An experiment in which subjects learned an environment from navigation or from a map evaluates predictions of these models. With moderate exposure, map learning is superior for judgments of relative location and straight-line distances among objects. Learning from navigation is superior for orienting oneself with respect to unseen objects and estimating route distances. With extensive exposure, the performance superiority of maps over navigation vanishes. These and other results are consonant with the proposed mechanisms.     

The gnosis of knowledge navigation on the Net

A set of activities developed to expose liberal arts undergraduates to global networking software and resources is detailed. Using a suite of Internet software tools and Macintosh computers, teams of students collaborated with faculty searching the World-Wide Web for on-line resources. Detailed student logs provide insights into the challenges of searching for Internet resources. Project shortcomings include difficulty in accessing information sites and poor organization of the final written reports. Ideas for improving the project in the future include allowing more time for the search process and replacing the written report with a WWW home page. The class project enhances the utilization of technology in the curriculum while equipping the students with computer skills to enhance their education.     

Cue combination in human spatial navigation

This project investigated the ways in which visual cues and bodily cues from self-motion are combined in spatial navigation. Participants completed a homing task in an immersive virtual environment. In Experiments 1A and 1B, the reliability of visual cues and self-motion cues was manipulated independently and within-participants. Results showed that participants weighted visual cues and self-motion cues based on their relative reliability and integrated these two cue types optimally or near-optimally according to Bayesian principles under most conditions. In Experiment 2, the stability of visual cues was manipulated across trials. Results indicated that cue instability affected cue weights indirectly by influencing cue reliability. Experiment 3 was designed to mislead participants about cue reliability by providing distorted feedback on the accuracy of their performance. Participants received feedback that their performance with visual cues was better and that their performance with self-motion cues was worse than it actually was or received the inverse feedback. Positive feedback on the accuracy of performance with a given cue improved the relative precision of performance with that cue. Bayesian principles still held for the most part. Experiment 4 examined the relations among the variability of performance, rated confidence in performance, cue weights, and spatial abilities. Participants took part in the homing task over two days and rated confidence in their performance after every trial. Cue relative confidence and cue relative reliability had unique contributions to observed cue weights. The variability of performance was less stable than rated confidence over time. Participants with higher mental rotation scores performed relatively better with self-motion cues than visual cues. Across all four experiments, consistent correlations were found between observed weights assigned to cues and relative reliability of cues, demonstrating that the cue-weighting process followed Bayesian principles. Results also pointed to the important role of subjective evaluation of performance in the cue-weighting process and led to a new conceptualization of cue reliability in human spatial navigation.     

Updating egocentric representations in human navigation

Seven experiments tested whether human navigation depends on enduring representations, or on momentary egocentric representations that are updated as one moves. Human subjects pointed to unseen targets, either while remaining oriented or after they had been disoriented by self-rotation. Disorientation reduced not only the absolute accuracy of pointing to all objects ('heading error') but also the relative accuracy of pointing to different objects ('configuration error'). A single light providing a directional cue reduced both heading and configuration errors if it was present throughout the experiment. If the light was present during learning and test but absent during the disorientation procedure, however, subjects showed low heading errors (indicating that they reoriented by the light) but high configuration errors (indicating that they failed to retrieve an accurate cognitive map of their surroundings). These findings provide evidence that object locations are represented egocentrically. Nevertheless, disorientation had little effect on the coherence of pointing to different room corners, suggesting both (a) that the disorientation effect on representations of object locations is not due to the experimental paradigm and (b) that room geometry is captured by an enduring representation. These findings cast doubt on the view that accurate navigation depends primarily on an enduring, observer-free cognitive map, for humans construct such a representation of extended surfaces but not of objects. Like insects, humans represent the egocentric distances and directions of objects and continuously update these representations as they move. The principal evolutionary advance in animal navigation may concern the number of unseen targets whose egocentric directions and distances can be represented and updated simultaneously, rather than a qualitative shift in navigation toward reliance on an allocentric map.     

Critical factors in consumer supermarket shopping behaviour: a neural network approach

This paper studies UK supermarket shopping behaviour, by analysing the antecedent variables of three critical factors: overall levels of customer satisfaction, number of trips to the supermarket, and amount spent. A neural network approach predicts these factors using ten input variables and three hidden nodes. Results show that the most satisfied and high‐spending customers tend to be those who have the income to take full advantage of the choice and quality offered. Other customers are more concerned with prices being reasonable and discounts available, but the satisfaction of these shoppers is also linked with store atmosphere. Copyright © 2001 Henry Stewart Publications.     

A technique for simulating visual field losses in virtual environments to study human navigation

The following paper describes a new technique for simulating peripheral field losses in virtual environments to study the roles of the central and peripheral visual fields during navigation. Based on Geisler and Perry's (2002) gaze-contingent multiresolution display concept, the technique extends their methodology to work with three-dimensional images that are both transformed and rendered in real time by a computer graphics system. In order to assess the usefulness of this method for studying visual field losses, an experiment was run in which seven participants were required to walk to a target tree in a virtual forest as quickly and efficiently as possible while artificial head and eye-based delays were systematically introduced. Bilinear fits were applied to the mean trial times in order to assess at what delay lengths breaks in performance could be observed. Results suggest that breaks occur beyond the current delays inherent in the system. Increases in trial times across all delays tested were also observed when simulated peripheral field losses were applied compared to full FOV conditions. Possible applications and limitations of the system are discussed. The source code needed to program visual field losses can be found at lions.med.jhu.edu/archive/turanolab/Simulated_Visual_Field_Loss_Code.html.     

Neuroevolution-based autonomous robot navigation: A comparative study

The field of neuroevolution has achieved much attention in recent years from both academia and industry. Numerous papers have reported its successful applications in different fields ranging from medical domain to autonomous systems. However, it is not clear which evolutionary optimization techniques lead to the best results. In this paper, multilayer perceptron (MLP) neural networks (NNs) are trained and optimized using four advanced bio-inspired evolutionary algorithms (EA). The algorithms are Multi-Verse Optimizer (MVO), Moth-flame optimization (MFO), Cuckoo Search (CS) and Particle Swarm Optimization (PSO). Each algorithm is equipped with two operators: evolutionary population dynamics and mutation, which impact on exploration and exploitation. Optimized MLPs are then used for the navigation of an autonomous robot. Accuracy and area under the curve metrics are used for the evaluation and comparison metrics. Moreover, two well-regarded gradient descent algorithms including Back propagation (BP) and Levenberg Marquardt (LM) are utilized to validate the results obtained by evolutionary-based MLP trainers. It is observed that MLPs developed using MFO are the most robust ones among MLPs trained using other evolutionary and gradient descent algorithms.     

Biomedical science in supermarket tabloids

Supermarket tabloids present, as truthful, stories about biomedical science that are greatly exaggerated and often fictitious. Apparently a sizable portion of their large readership accepts these stories as correct. This is "scientific journalism" at its worst, but its standards are not wholly different from those of the mainline press. Reprinted from Knowledge and Policy: The International Journal of Knowledge Transfer and Utilization, Fall 1989, Vol. 2, No. 3, pp. 74–81. Allan Mazur is both a sociologist and a technologist. He received an M.S. in Engineering from UCLA and worked for several years as an aerospace engineer before obtaining a Ph.D. in sociology from Johns Hopkins University. He has been a member of the social science faculties of MIT and Stanford University, and is currently a professor in Syracuse University’s Maxwell School of Citizenship and Public Affairs. The Dynamics of Technical Controversy (1981) is his major work on public disputes over technology, and he continues to work in this area as well as in biosociology.     

Lost in virtual space: studies in human and ideal spatial navigation

The authors describe 3 human spatial navigation experiments that investigate how limitations of perception, memory, uncertainty, and decision strategy affect human spatial navigation performance. To better understand the effect of these variables on human navigation performance, the authors developed an ideal-navigator model for indoor navigation whose optimizing algorithm uses a partially observable Markov decision process. The model minimizes the number of actions (translations and rotations) required to move from an unknown starting state to a specific goal state in indoor environments that have perceptual ambiguity. The authors compared the model's performance with that of the human observer to measure human navigation efficiency. Experiment 1 investigated the effect of increasing the layout size on spatial way-finding efficiency and found that participants' efficiencies decreased as layout size increased. The authors investigated whether this reduction in navigation efficiency was due to visual perception (Experiment 2), memory, spatial updating strategy, or decision strategy (Experiment 3).     

The retrosplenial contribution to human navigation: a review of lesion and neuroimaging findings

The clinical and neuroimaging literatures are surveyed in order to collate for the first time the available data on retrosplenial involvement in human navigation. Several notable features emerge from consideration of the case reports of relatively pure topographical disorientation in the presence of a retrosplenial lesion. The majority of cases follow damage to the right retrosplenial cortex, with Brodmann's area 30 apparently compromised in most cases. All patients displayed impaired learning of new routes, and defective navigation in familiar environments complaining they could not use preserved landmark recognition to aid orientation. The deficit generally resolved within eight weeks of onset. The majority of functional neuroimaging studies involving navigation or orientation in large-scale space also activate the retrosplenial cortex, usually bilaterally, with good concordance in the locations of the voxel of peak activation across studies, again with Brodmann's area 30 featuring prominently. While there is strong evidence for right medial temporal lobe involvement in navigation, it now seems that the inputs the hippocampus and related structures receive from and convey to right retrosplenial cortex have a similar spatial preference, while the left medial temporal and left retrosplenial cortices seem primarily concerned with more general aspects of episodic memory.     

Place navigation in mammals: a configuration-based model

Recent water maze experiments suggest that rats performing place navigation primarily use the geometric information provided by a set of landmarks, and neglect the featural information provided by the identities of the landmarks. Here, I develop a model that explains how an animal may perform place navigation by relying only on geometric information. The core of the model is the representation of places as panoramas defined by circular bar-codes embodying the relative bearings and apparent sizes of the landmarks, irrespective of their identities. There are two stages in the model. During the first stage, the animal freely explores its environment in order to acquire spatial information at the local level. During the second stage, the animal uses the information previously memorized to perform place navigation towards the goal it intends to reach. The possible role of two brain areas in place navigation is discussed within this framework. Beyond their primary role in landmark-based representations of places, hippocampal place cells may be involved in computing the current distances to the landmarks. Beyond their primary role in landmark-based representations of headings, post-subicular head-direction cells may be involved in computing the “compass bearings” of the landmarks. Received: 17 January 1998 / Accepted after revision: 19 April 1998     

Biomedical science in supermarket tabloids

Supermarket tabloids present, as truthful, stories about biomedical science that are greatly exaggerated and often fictitious. Apparently a sizable portion of their large readership accepts these stories as correct. This is “scientific journalism” at its worst, but its standards are not wholly different from those of the mainline press. Allan Mazur is both a sociologist and a technologist. He received an M.S. in Engineering from UCLA and worked for several years as an aerospace engineer before obtaining a Ph.D. in sociology from Johns Hopkins University. He has been a member of the social science faculties of MIT and Stanford University, and is currently a professor in Syracuse University's Maxwell School of Citizenship and Public Affairs.The Dynamics of Technical Controversy (1981) is his major work on public disputes over technology, and he continues to work in this area as well as in biosociology.     

Drivers' knowledge, attitudes, and behavior: a cross-sectional study

A cross-sectional survey was conducted by random duster sampling in the city of Tehran. Knowledge of the drivers was assessed with 6 questions about national traffic laws. Attitude was assessed on a 7-item scale of drivers' perceptions. Behavior was observed by a police officer on 13 areas of assessment. Correlations were low among these three scores. Drivers with advanced education had higher scores on behavior. Knowledge, attitude, and behavior of these drivers did not seem associated.     

Spatial knowledge acquisition from maps and from navigation in real and virtual environments

In this study, the nature of the spatial representations of an environment acquired from maps, navigation, and virtual environments (VEs) was assessed. Participants first learned the layout of a simple desktop VE and then were tested in that environment. Then, participants learned two floors of a complex building in one of three learning conditions: from a map, from direct experience, or by traversing through a virtual rendition of the building. VE learners showed the poorest learning of the complex environment overall, and the results suggest that VE learners are particularly susceptible to disorientation after rotation. However, all the conditions showed similar levels of performance in learning the layout of landmarks on a single floor. Consistent with previous research, an alignment effect was present for map learners, suggesting that they had formed an orientation-specific representation of the environment. VE learners also showed a preferred orientation, as defined by their initial orientation when learning the environment. Learning the initial simple VE was highly predictive of learning a real environment, suggesting that similar cognitive mechanisms are involved in the two learning situations.     

Sex differences in historical knowledge and school grades: a 26 nation study

Sex differences among ninth grade school students in historical knowledge and grades were examined in 29 samples drawn from 26 countries. Boys obtained higher mean scores on the tests of historical knowledge in all samples, while girls obtained better grades in 22 of the samples.