Environmental reference systems for large-scale spaces

Human navigation in well-known environments is guided by stored memory representations of spatial information. In three experiments (N = 43) we investigated the role of different spatial reference systems when accessing information about familiar objects at different locations in the city in which the participants lived. Our results indicate that two independent reference systems underly the retrieval of spatial knowledge. Environmental characteristics, e.g., the streets at an intersection, determine which headings are easier to imagine at a given location and lead to differences in accessibility of spatial information (orientation-specific behavior). In addition, access to spatial information depends on the relative direction of a location with respect to the imagined heading, such that information about locations imagined in front of oneself is easier to access than about locations towards the back. This influence of an egocentric reference system was found for environmental knowledge as well as map-based knowledge. In light of these reference system effects, position-dependent models of spatial memory for large-scale environments are discussed. To account for the simultaneous effect of an environmental and an egocentric reference system, we present a 2-level model of spatial memory access.     

Children's control of reference systems in spatial tasks: Foundations of spatial cognitive skill?

Two experiments are presented, one that focused on the abilities of 3- through 8-year-old children to use frames of reference as means for solving a search task in a small-scale perceived space and one that focused on the abilities of 8- through 11-year-old children to use different frames of reference to answer questions about the locations of objects in an environment they had read about. Experiment 1 revealed developmental improvement in the consistent application of object-, place-, and viewer-based frames of reference, with scale of space impacting the pattern of age-related improvement. Experiment 2 showed that young readers' first successes with switching from one reference system to another in representational space involved a vantage point perspective, a viewer-based ``gaze tour' of a small-scale area. Although disparate in focus and method, the studies point to the need for a new theoretical framework for examining developmental issues in the application of spatial frames of reference.     

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.     

Revisiting Perspective-Taking: Can People Maintain Imagined Perspectives?

Abstract

Three experiments were conducted to examine whether people can adopt and maintain imagined perspectives in the absence of target information. The task used entailed providing information about an imagined perspective in advance of target information to examine whether this would facilitate perspective-taking performance and reduce or eliminate alignment effects that are commonly reported in the literature. The three experiments employed different types of spatial environments: an environment learned from navigating a computer screen (Experiment 1), and an immersive environment that was either remote (Experiment 2) or immediate (Experiment 3) at the time of retrieval. Across the three experiments, results showed that information about an imagined perspective can be utilized ahead of target information. Furthermore, they suggested that alignment effects can be reduced as a result of processing information about perspective ahead of target information, but only when reasoning about specific nonimmediate spatial relations (Experiments 1 and 2). Results are discussed in connection with previous findings on spatial updating and the organizational structure of spatial memory.     

Selecting a reference frame

Reference frames are representations that parse space. In the case of spatial terms, reference frames mediate the mapping of linguistic expressions onto spatial configurations of objects. In the sentence ``The fly is above the cat,' ``above' is defined with respect to a reference frame that is imposed on the cat. Different types of reference frames can be used to define spatial terms, each based on a different source of information. For example, gravity, the orientation of objects in the scene or the orientation of the viewer can all be used to set the orientation of a reference frame. When these reference frames disagree (because the viewer is reclining or because the objects in the scene are overturned), there are competing definitions for the spatial term, resulting in the need for reference frame selection. The purpose of this paper is to review a line of research that examines reference frame selection in the context of spatial language. This work shows that all reference frames are initially active and assign a direction to a spatial term. Moreover, this activation is automatic, and is followed by the selection of a single reference frame, with selection accompanied by inhibition of the non-selected frames. Parallels between reference frame selection in language and in perception and attention are discussed.     

Editorial: Cognitive Semantics and Spatio-Temporal Ontologies

How do people describe the location of a target object to another? This task requires a reference object or frame and terms of reference. Traditional linguistic analyses have loosely organized perspectives around people, objects, or environments as reference objects, using reference terms based on a viewpoint or the intrinsic sides of an object, such as left, right, front, and back or based on the environment, such as north, south, east, and west. In actual communication, social, spatial, and cognitive factors may also affect perspective choice. We examine those factors by varying the spatial information (landmarks and cardinal directions), the communication task (relative cognitive burden to speakers and addressees), and the culture of participants (American and Japanese). Speakers used addressees' perspectives more when addressees had the greater cognitive burden. They also used landmarks and cardinal directions when they were available, especially to avoid difficult discriminations like left/right. Some cases appearing to be perspective taking can be interpreted as using a person as a landmark. Finally, terms like near indicating close proximity were preferred to far and to terms requiring projection of directions. Globally, perspective choices of American and Japanese samples were strikingly similar; that is, Japanese did not select addressees' perspectives more than Americans. The traditional linguistic analyses need to be enhanced to account for effects of cognitive, situational, and social factors.     

Spatial Memory Organized by Environmental Geometry

We investigated the simultaneous effects of different reference systems on spatial memory. Participants studied a configuration of objects surrounding them. During retrieval, they imagined themselves in the center of the object configuration facing a particular object, and then indicated the directions of other objects relative to this imagined heading. Besides strong effects of egocentric retrieval direction, retrieval was enhanced for objects and headings aligned with an object-centered reference system (triangular object configuration within a neutrally-shaped room), or with a sufficiently salient environmental reference system (triangular room surrounding a neutrally-shaped object configuration). Moreover, remembered object positions were spatially distorted by the object-centered reference system. Results suggest that object positions are accessed by imagining oneself within a topographical representation of objects which is preorganized in terms of both environmental and object-centered reference systems.     

The effect of the configuration and the interior design of a virtual weightless space station on human spatial orientation

In a virtual weightless environment, subjects’ orientation skills were studied to examine what kind of cognitive errors people make when they moved through the interior space of virtual space stations and what kind of visual information effectively decreases those errors. Subjects wearing a head-mounted display moved from one end to the other end in space station-like routes constructed of rectangular and cubical modules, and did Pointing and Modeling tasks. In Experiment 1, configurations of the routes were changed with such variables as the number of bends, the number of embedding planes, and the number of planes with respect to the body posture. The results indicated that spatial orientation ability was relevant to the variables and that orientational errors were explained by two causes. One of these was that the place, the direction, and the sequence of turns were incorrect. The other was that subjects did not recognize the rotation of the frame of reference, especially when they turned in pitch direction rather than in yaw. In Experiment 2, the effect of the interior design was examined by testing three design settings. Wall colors that showed the allocentric frame of reference and the different interior design of vertical and horizontal modules were effective; however, there was a limit to the effectiveness in complicated configurations.     

The Effect of an Extra Object on the Linguistic Apprehension of the Spatial Relationship between Two Objects

A sentence describing a spatial relationship includes at least two objects: a located object and a reference object. The presence of an extra object in a scene that is recognized as neither a located nor a reference object, reduces the acceptability of spatial terms related to the spatial relationship between reference and located objects under given conditions (Carlson & Logan, 2001). However, it is still unclear how the overall acceptability distribution of a spatial term changes in a scene when an extra object is present in various locations. In this study, we examined this point, using the paired comparison method with Thurstone's law of judgment (Case V). The results showed that an extra object had both relative increase and reduction effects on the overall acceptability distribution of a spatial term. This suggests that our linguistic apprehension of the spatial relationship is biased intricately by the presence of extra objects.     

Egocentric frames of reference used for the retrieval of survey knowledge learned by map and navigation

Two experiments are reported that use a ``point-to-unseen-targets' task to study the role of egocentric reference frames in the retrieval of survey knowledge learned from either studying a map or navigating an environment. In Experiment 1, performance was generally consistent with the hypothesis that map knowledge is retrieved using a frame of reference centered on the eye, characterized by (a) a fixed orientation in a ``frontal representational plane' and (b) equal access to spatial relations both in front of, or above, and behind, or below, a right-left retrieval axis. The results of Experiment 2 were consistent with the hypothesis that environment knowledge is retrieved within a frame of reference centered on the body, characterized by (a) flexible orientation within a ``transverse representational plane' and (b) privileged access to spatial relations located in front of the right-left retrieval axis in representational space. Both types of knowledge function as if they preserve information about the Euclidean angles connecting elements in physical space.     

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.     

Seeing the Forest or the Trees? Shifting Categorical Effects in Map Memory

People use spatial and nonspatial information to structure memory for an environment. Two experiments explored interactions between spatial and social categories on map memory when mediated by retrieval (Experiment 1) and encoding (Experiment 2) demands. Participants studied a map depicting business locations (including proprietors' race). In Experiment 1, participants completed two memory tasks, one globally focused and the other locally focused. The global task compressed, while the local task expanded, within-category similarity. Furthermore, processing styles carried over to the subsequent task. Experiment 2 emphasized either the spatial or social category during encoding, which increased that category's weighting in memory. These results extend the work of Maddox, Rapp, Brion, and Taylor, suggesting that retrieval and encoding demands can shift how these categories affect spatial memory.     

Spatial updating and common misinterpretations of spatial reference frames

Spatial memory plays an important role in everyday life, and a large amount of research has been devoted to understanding spatial coding and reference frames across many areas. The popular research paradigms to study spatial reference frames include novel shortcut, perspective change, and landmark control tests. However, the growing research on spatial updating challenges the logical foundation of these classical paradigms, and suggests that the experimental findings using these paradigms have usually been misinterpreted. That is, performance in these tasks is generally unrelated to whether the spatial representations themselves are egocentric or allocentric. This article reviews the traditional paradigms and their logic, summarizes the theories of spatial updating, analyzes the logical flaws in these popular paradigms, and discusses their implications.     

Spatial Reference in Linguistic Human-Robot Interaction: Iterative,Empirically Supported Development of a Model of Projective Relations

The aim of our research is to enable spontaneous and efficient spatial reference to objects in human-robot interaction situations. This paper presents the iterative, empirically based design of a robotic system that uses a computational model for identifying objects on the basis of a range of spatial reference systems. The efficiency of the system is evaluated by two successive empirical studies involving uninformed users. The linguistic analysis points to the striking variability in speakers' spontaneous strategies and preferences, and it motivates a number of modifications of the computational model.     

The face inversion effect in microgravity: is gravity used as a spatial reference for complex object recognition?

Complex objects are better recognized under a specific orientation. When presented upside down, a face, even very familiar, is recognized with greater difficulty than when presented upright ("Inversion effect"). Up to now it was not possible to decide whether the direction provided by gravity or the one provided by the retina and the body constitutes the spatial reference involved in this "Inversion effect". Three cosmonautes learned photographed faces on the ground and had to recognize them both on ground and on flight. Other photographed faces were learned in flight and where presented for recognition on flight. Results show that the Inversion effect is still present on flight for faces that have been learned on ground as well as for those learned on flight. Persistence of the inversion effect in 0-G shows that gravity is not involved as a spatial reference in recognition of faces. Learning and recognition performances of faces learned in flight were significantly lower than performances for faces learned on ground. A possible role of gravity in configural processing, but not in the Inversion effect, is suggested.     

Which way is the bookstore? A closer look at the judgments of relative directions task

We present a detailed analysis of a widely used assay in human spatial cognition, the judgments of relative direction (JRD) task. We conducted three experiments involving virtual navigation interspersed with the JRD task, and included confidence judgments and map drawing as additional metrics. We also present a technique for assessing the similarity of the cognitive representations underlying performance on the JRD and map-drawing tasks. Our results support the construct validity of the JRD task and its connection to allocentric representation. Additionally, we found that chance performance on the JRD task depends on the distribution of the angles of participants’ responses, rather than being constant and 90 degrees. Accordingly, we present a method for better determining chance performance.     

Young Children's Perception of Diagrammatic Representations

Diagrams and pictorial representations are common in children's lives and require abstraction away from visual perception. In three experiments, we investigated 4- to 8-year-olds’ comprehension of such representations. In Experiment 1 (N = 80), children were shown photographs of geometric objects and asked to choose the corresponding line drawing from among sets of four, or vice versa. Results showed considerable developmental progression, especially around age 6. Experiment 2 (N = 16) ruled out that 4-year-olds’ difficulties were due to problems with the visual matching task itself. Experiment 3 (N = 32) showed comparable performance for matching diagrams to 3D objects rather than to photographs. Findings suggest increasing understanding of diagrammatic representations around the time of school entry.