Is Memory for Routes Enhanced by an Environment's Richness in Visual Landmarks?

We tested the hypothesis that a route's memorability is dependent on the frequency with which people are exposed to visual landmarks. Undergraduates learned either a route through an urban area lacking visually salient features, or a route in a neighborhood with many shops and urban objects. They were then asked to recall the learned route in the form of route directions and sketch maps. The results showed higher recall performance for the richer environment. When presented with photographs depicting scenes along the route, participants exposed to the richer environment had higher recognition scores and shorter response times than the others. The data confirm the functional role of landmarks in route memory and wayfinding.     

How Navigational Aids Impair Spatial Memory: Evidence for Divided Attention

Abstract

Research has demonstrated navigational aids impair spatial memory, but has not considered important spatial cognitive concepts. For example, impairment may stem from spatial perspective switches between route-based aids and survey-based memory assessments. Further, the verbal format of aid instructions may selectively interfere with verbal working memory (VWM). To address these potential explanations, participants navigated desktop virtual environments in a goal-directed manner. In each within-participants condition, participants either navigated with a verbal or tonal aid that presented mixed spatial perspective instructions or without aid. Both aids yielded slight navigational advantages and steep spatial memory costs despite their mixed perspective instructions. The equivalent impairment between information formats suggests navigational aids impair spatial memory by dividing attention rather than selective interference of VWM.     

Selection of Salient Features for Route Directions

People navigating in unfamiliar environments rely on wayfinding directions, either given by people familiar with the place, or given by maps or wayfinding services. The essential role of landmarks in human route communication is well-known. However, mapping the human ability to select landmarks ad hoc for route directions to a computational model was never tried before. Wayfinding services manage the problem by using predefined points of interest. These points are not automatically identified, and they are not related to any route. In contrast, here a computational model is presented that selects salient features along a route where needed, e.g., at decision points. We propose measures to formally specify the salience of a feature. The observed values of these measures are subject to stochastical tests in order to identify the most salient features from datasets. The proposed model is implemented and checked for computability with a use case from the city of Vienna. It is also crosschecked with a human subject survey for landmarks along a given route. The survey provides evidence that the proposed model selects features that are strongly correlated to human concepts of landmarks. Hence, integrating the selected salient features in wayfinding directions will produce directions with lower cognitive workload and higher success rates, compared to directions based only on geometry, or on geometry and static points of interest.     

The Influence of Landmarks and Pre-exposure to a Structural Map During the Process of Spatial Knowledge Acquisition: A Study with Children and Adults in a Virtual Environment

ABSTRACT

This study investigated the effects of featural information (landmarks) and geometric information (pre-exposure to a structural map) and their possible interaction during the process of spatial knowledge acquisition of 8- and 11-year-old children and adults in a virtual environment. The study confirmed the well-known result of a developmental achievement in spatial cognition from childhood to adulthood. Although landmarks and the pre-exposure to a structural map did not affect the time to learn a specific route, they influenced the use of behavior in spatial learning and eased the acquisition of spatial knowledge measured by a route reversal and map-drawing tasks. Children and adults are able to integrate featural and geometric information in the spatial knowledge acquisition process in an environmental space, but their integration depends on the spatial processing stages that are investigated. Moreover, it was successfully demonstrated that the use of desktop virtual environments seems to be appropriate to investigate the development of spatial cognition.     

An analysis of peculiarities of the satellite autonomous navigation in sighting unknown landmarks on the planet surface

An analysis of characteristics of autonomous navigation by using optical sighting of unknown landmarks was carried out for artificial satellites in circular orbits around the Earth with altitudes from 300 to 900 km. It is shown that navigational errors vary approximately in inverse proportion to duration of measurements. Also they decrease with an increasing number of sighted landmarks. The errors poorly depend on the orbit altitude if the duration of measurement for each landmark is chosen in proportion to the orbit altitude, or a maximal zenith angle of sighting the landmark remains constant.Some characteristics of the navigational algorithm are given. Admissible deviations of initial orbital elements from their exact values are investigated. For a properly chosen measurement procedure the algorithm proves to be stable even for rather crudely given initial parameters.     

Is Route Learning More Than Serial Learning?

Abstract

The nature of route learning in terms of the memorizing of landmarks was investigated. In Experiment 1, participants memorized landmarks while being guided through a computer-simulated hallway (dynamic, with spatial context), or while viewing the landmarks one by one in front of a black background (static, without context). Two more conditions completed the 2 × 2 design. One condition preserved the dynamic landmark viewing properties (observers approached each object, passed it, turned to the next object, and so on), but the background was black (dynamic, without context). In the other condition the observer saw a stationary display of each object within a hallway, but did not approach the object (static, with context). Serial recall was much better after viewing the landmarks in the dynamic presentation format with spatial context than in the other conditions. Experiment 2 showed that the superior performance in the dynamic condition with context was abolished when all hallway segments were equally long. This implies that metric information is a component of route knowledge at a very early stage, which is incompatible with the dominant framework, but is compatible with the alternative framework for spatial microgenesis.     

Landmarks on the move: Producing and understanding references to moving landmarks

There is a general agreement that landmarks in route directions should be perceptually salient and stable objects. Yet, other attributes, such as (animated) motion, can also attract visual attention and make entities salient. In the present study, we investigate if and when speakers refer to moving entities in route directions and how listeners evaluate such instructions. We asked speakers to watch short videos of different crossroads with and without moving landmarks and give directions to listeners, who in turn had to choose a street on which to continue (Experiment 1) or choose the instruction they most preferred among three route directions (Experiment 2). Results reveal that speakers mentioned moving entities, especially when the trajectory was informative for the place where a turn should be taken (Experiment 1). Listeners had no problem understanding instructions with moving landmarks (Experiment 1). Yet, participants chose instructions with stable landmarks more often (Experiment 2). These results are discussed in relation to automatic route directions generation.     

Navigational Aids and Spatial Memory Impairment: The Role of Divided Attention

Navigational aids impair spatial memory for experienced environments, but the cognitive mechanisms underlying impairment remain an open question. Recent evidence implicates divided attention, but to date no study has directly manipulated divided attention in navigational aid contexts. The present study addresses this need. Participants navigated virtual towns with aid presence and divided attention factorially crossed in a within-participants design. They then completed spatial memory assessments. Divided attention alone impaired spatial memory. Navigational aid presence impaired spatial memory when attention was undivided, replicating previous findings, but did not to a greater extent when attention was divided. These findings suggest that navigational aids divide attention sufficiently to impair spatial memory.     

Path Integration During a Neighborhood Walk

In three experiments, we contrast two accounts of path integration processes that track direction and distance of movement. Moment-to-moment updating involves the continuous sensing of motion; automatic calculations constantly produce an estimate of position and orientation of self to an anchor point for travel. In contrast, configural updating can be accomplished using episodic memories; a representation of the traveled path is periodically revised and the bearing to the origin of a route can be estimated by connecting the endpoint of the current leg to the starting point of the first leg. Experiments 1 and 3 indicate that people encode the number and direction of turns but have difficulty configuring more gradually curved legs. In Experiment 2, we find that blindfolded people show better than chance performance in estimating the origin of outdoor routes when they are unexpectedly asked to point. It appears that, in addition to episodic memories that allow configural updating, we have available a moment-to-moment representation of our position and heading based on the cues that accompany self-movement.     

The New Generation of Automatic Landmark Detection Systems: Challenges and Guidelines

Abstract

Landmarks are salient objects in an environment. They play an important role in navigation by serving as orientation aids and marking decision points. Recently, there have been several efforts to design methods to automatically designate certain buildings with salient features as landmarks. All of these methodologies consist of similar steps: (a) establishing a neighborhood, usually around an intersection, (b) performing statistical or data mining analysis to find the building with outlier characteristics, and (c) establishing this salient building as the local landmark. Although these advances are significant, we believe that there are still several key issues that need to be fully addressed in order to realize the new generation of Automatic Landmark Detection Systems (ALDSs). Currently, the main shortcomings in the domain of ALDSs is the lack of a thorough and systematic study of attributes of objects that are analyzed to select landmarks, and deficient experimental verification of the benefits of ALDSs to the end users. Unless, these shortcomings are thoroughly addressed, the viability, applicability, and usefulness of ALDSs are uncertain. On the other hand, automatic landmark detection has the potential to be a dynamic, fascinating, and interdisciplinary research topic with wide applicability. Therefore, the goal of this paper is to discuss the current shortcomings in the domain of landmark detection, propose some preliminary solutions, and provide general guidelines for implementation of the new generation of ALDSs. Specifically, we discuss and promote the importance of: (a) widening the types of attributes analyzed in the landmark detection process, (b) weighting each attribute relative to its significance, (c) extending the types of objects considered as landmark candidates beyond just buildings, (d) identifying landmarks outside the vicinity of intersections, (e) identifying false landmarks along routes, and (f) using virtual environments for experiments with ALDSs. Throughout the paper, we discuss several demonstrative examples and experiments to clarify and support the ideas and concepts that are being promoted.     

The effects of maps and textual information on navigation in a desktop virtual environment

This study presents an experimentthat investigates how individuals perform anavigation test in a desktop virtualenvironment. The participants were randomlyassigned to one of the five test conditions:(C1) a map as information material during theentire test, (C2) the map only visible beforethe test, (C3) textual information during theentire test, (C4) textual information onlybefore the test and (C5) no additionalnavigational cues. The results were thatadditional information during the entire testwas more effective than short periods ofstudying the map or textual information onlybefore the test. However, participants weremore accurate in finding their route when anykind of navigational cues were used than whenno navigational cues were used. The results ofan additional questionnaire indicate thatbetween the test groups there were nodifferences in estimating the travelleddistances. The performance to draw the coveredpath into a sketch map of the landscape did notdiffer significantly between the test groupswith additional navigational cues. Theseresults indicate that in certain environmentstextual information may provide an effectivealternative to navigation training with a map.     

Learning relative directions between landmarks in a desktop virtual environment

This study presents two experiments that examine howindividuals learn relative directions betweenlandmarks in a desktop virtual environment. Subjectswere presented snapshot images of different virtualenvironments containing distinguishing landmarks anda road network. Following the presentation of eachvirtual environment, subjects were given a relativedirection test. The relative direction test involvedindicating the direction of hidden landmarks fromdifferent vantage points in the environment. Half ofthese vantage points were presented during thelearning phase, while the other half were novel.Results showed that subjects learned relativedirections between landmarks equally well when sceneswere presented in either a sequential or random order.Furthermore, viewing a configuration of landmarks ina desktop virtual environment from multipleperspectives produced a viewpoint dependentrepresentation in memory. Subjects had significantlygreater response times for new viewing perspectives,as compared to previously viewed scenes. Thisviewpoint dependent representation of the environmentpersisted despite learning under conditions ofspatio-temporal discontinuity and changes to anenvironmental frame of reference.     

Development of Landmark Knowledge at Decision Points

Two experiments investigated how people develop different landmark knowledge at decision points. Participants learned a route in a virtual city once or five times. One distinctive landmark was placed at each intersection of the route. At test, participants were released at each intersection according to the learning order and were required to determine the turning direction. At each intersection, the landmark was removed (no landmark), correctly placed (one landmark), duplicated on the other side (two identical landmarks), or misplaced from another intersection (two different landmarks) to disrupt the landmark sequence. The results suggested that humans develop different landmark knowledge (landmark knowledge for guidance, landmark knowledge for place recognition and knowledge of landmark sequence) with different navigation experience.     

Variable Granularity in Route Directions

Abstract

This paper addresses changes of spatial granularity in route directions in relation to information needs in multimodal traveling. We outline a model of variability in granularity and apply this model to empirical data. Results reveal that linguistic route directions produced by humans as well as automatically generated web-based services provide the most crucial route elements in hierarchically structured ways that reflect the salient structure imposed by multimodal traveling. However, although the web-based information is impressively comprehensive, human route directions exhibit more flexibility regarding switches of place-related granularity, and they provide more detailed information at complex locations or decision points.     

The acquisition of survey knowledge for local and global landmark configurations under time pressure

The influence of stress states on cognition is widely recognized. However, the manner in which stress affects survey knowledge acquisition is still unresolved. For the present study, we investigated whether survey knowledge acquisition during a stressful task (i.e., under time pressure) is more accurate for the mental representation of global or local landmarks. Participants navigated through virtual cities with a navigation aid and explicit learning instructions for different landmark configurations. Participants’ judgments of relative direction (JRDs) suggest that global landmark configurations were not represented more accurately than local landmark configurations and that survey knowledge acquisition was not impaired under time pressure. In contrast to prior findings, our results indicate the limitations of the utility of global landmarks for spatial knowledge acquisition.