Unidirectional influence of vision on locomotion in multimodal spatial representations acquired from navigation.

Visual and idiothetic information is coupled in forming multimodal spatial representations during navigation (Tcheang et al. in Proc Natl Acad Sci USA 108(3):1152-1157, 2011). We investigated whether idiothetic representations activate visual representations but not vice versa (unidirectional coupling) or whether these two representations activate each other (bidirectional coupling). In a virtual reality environment, participants actively rotated in place to face certain orientations to become adapted to a new vision-locomotion relationship (gain). In particular, the visual turning angle was equal to 0.7 times the physical turning angle. After adaptation, participants walked a path with a turn in darkness (idiothetic input only) or watched a video of the traversed path (visual input only). Then, the participants pointed to the origin of the path. The participants who were presented with only idiothetic input showed that their pointing responses were influenced by the new gain (adaptation effect). By contrast, the participants who were presented with only visual input did not show any adaptation effect. These results suggest that idiothetic input contributed to spatial representations indirectly via the coupling, which resulted in the adaptation effect, whereas vision alone contributed to spatial representations directly, which did not result in the adaptation effect. Hence, the coupling between vision and locomotion is unidirectional.

Selective resetting position and heading estimations while driving in a large-scale immersive virtual environment.

Two experiments investigated how self-motion cues and landmarks interact in determining a human's position and heading estimations while driving in a large-scale virtual environment by controlling a gaming wheel and pedals. In an immersive virtual city, participants learned the locations of five buildings in the presence of two proximal towers and four distal scenes. Then participants drove two streets without viewing these buildings, towers, or scenes. When they finished driving, either one tower with displacement to the testing position or the scenes that had been rotated reappeared. Participants pointed in the directions of the five buildings. The least squares fitting method was used to calculate participants' estimated positions and headings. The results showed that when the displaced proximal tower reappeared, participants used this tower to determine their positions, but used self-motion cues to determine their headings. When the rotated distal scenes reappeared, participants used these scenes to determine their headings. If they were instructed to continuously keep track of the origin of the path while driving, their position estimates followed self-motion cues, whereas if they were not given instructions, their position estimates were undetermined. These findings suggest that when people drive in a large-scale environment, relying on self-motion cues, path integration calculates headings continuously but calculates positions only when they are required; relying on the displaced proximal landmark or the rotated distal scenes, piloting selectively resets the position or heading representations produced by path integration.

The limits of boundaries: unpacking localization and cognitive mapping relative to a boundary.

Previous research (Zhou, Mou, Journal of Experimental Psychology: Learning, Memory and Cognition 42(8):1316-1323, 2016) showed that learning individual locations relative to a single landmark, compared to learning relative to a boundary, led to more accurate inferences of inter-object spatial relations (cognitive mapping of multiple locations). Following our past findings, the current study investigated whether the larger number of reference points provided by a homogeneous circular boundary, as well as less accessible knowledge of direct spatial relations among the multiple reference points, would lead to less effective cognitive mapping relative to the boundary. Accordingly, we manipulated (a) the number of primary reference points (one segment drawn from a circular boundary, four such segments, vs. the complete boundary) available when participants were localizing four objects sequentially (Experiment 1) and (b) the extendedness of each of the four segments (Experiment 2). The results showed that cognitive mapping was the least accurate in the whole boundary condition. However, expanding each of the four segments did not affect the accuracy of cognitive mapping until the four were connected to form a continuous boundary. These findings indicate that when encoding locations relative to a homogeneous boundary, participants segmented the boundary into differentiated pieces and subsequently chose the most informative local part (i.e., the segment closest in distance to one location) as the primary reference point for a particular location. During this process, direct spatial relations among the reference points were likely not attended to. These findings suggest that people might encode and represent bounded space in a fragmented fashion when localizing within a homogeneous boundary.

Look up: Human adults use vertical height cues in reorientation.

Numerous studies have shown that people and other animals readily use horizontal geometry (distance and directional information) to reorient, and these cues sometimes dominate over other cues when reorienting in navigable environments. Our study investigated whether horizontal cues (distance/angle) dominate over vertical cues (wall height) when they are in conflict. Adult participants learned two locations (opposite corners) in either a rectangular room (with distance information) or a rhombus room (with angle information). Both training rooms had 2 opposite high walls as height cues. On each trial, participants were disoriented and then asked to locate the correct corners. In testing, the rooms were modified to provide (a) distance or angle cues only, (b) height cues only, and (c) both height and horizontal cues in conflict. Participants located the correct corners successfully with horizontal (distance/angle) or height cues alone. On conflict tests, participants did not show preference for the horizontal information (distance/angle) over the height cues. The results are discussed in terms of the geometric module theory and the adaptive combination theory.

Relative cue precision and prior knowledge contribute to the preference of proximal and distal landmarks in human orientation.

A prevailing argument posits that distal landmarks dominate over proximal landmarks as orientation cues. However, no studies have tested this argument or examined the underlying mechanisms. This project aimed to close this gap by examining the roles of relative cue precision and prior knowledge in cue preference. Participants learned object locations with proximal and distal landmarks in an immersive virtual environment. After walking a path without seeing objects or landmarks, participants disoriented themselves by spinning in place and pointed to the objects with the reappearance of a proximal landmark being rotated -50°, a distal landmark being rotated 50°, or both (Conflict). Heading errors were examined. Experiment 1 manipulated the relative cue precision. Results showed that in Conflict condition, the observed weight on the distal cue (exceeding 0.5) changed with but remained higher than the weight predicted by the relative cue precision. This indicates that besides the relative cue precision, prior knowledge of distal cue dominance also influences orientation cue usage. In Experiments 2 and 3, participants walked a path stopping at one object location. Participants were informed of it explicitly in Experiment 2 but not in Experiment 3. Results showed that distal cue dominance still occurred in Experiment 3. However, in Experiment 2, proximal cue dominance appeared, and it was not predicted by the relative cue precision. These results suggest that prior knowledge of proximal cue dominance might have been invoked by the instruction of locations. Consistent with the Bayesian inference model, human cue usage in orientation is determined by relative cue precision and prior knowledge. The choice of prior knowledge can be influenced by instructions.

Path integration, rather than being suppressed, is used to update spatial views in familiar environments with constantly available landmarks.

This project tested three hypotheses conceptualizing the interaction between path integration based on self-motion and piloting based on landmarks in a familiar environment with persistent landmarks. The first hypothesis posits that path integration functions automatically, as in environments lacking persistent landmarks (environment-independent hypothesis). The second hypothesis suggests that persistent landmarks suppress path integration (suppression hypothesis). The third hypothesis proposes that path integration updates the spatial views of the environment (updating-spatial-views hypothesis). Participants learned a specific object's location. Subsequently, they undertook an outbound path originating from the object and then indicated the object's location (homing). In Experiments 1&1b, there were landmarks throughout the first 9 trials. On some later trials, the landmarks were presented during the outbound path but unexpectedly removed during homing (catch trials). On the last trials, there were no landmarks throughout (baseline trials). Experiments 2-3 were similar but added two identical objects (the original one and a rotated distractor) during homing on the catch and baseline trials. Experiment 4 replaced two identical objects with two groups of landmarks. The results showed that in Experiments 1&1b, homing angular error on the first catch trial was significantly larger than the matched baseline trial, undermining the environment-independent hypothesis. Conversely, in Experiment 2-4, the proportion of participants who recognized the original object or landmarks was similar between the first catch and the matched baseline trial, favoring the updating-spatial-views hypothesis over the suppression hypothesis. Therefore, while mismatches between updated spatial views and actual views of unexpected removal of landmarks impair homing performance, the updated spatial views help eliminate ambiguous targets or landmarks within the familiar environment.

Reorientation in diamond-shaped environments: encoding of features and angles in enclosures versus arrays by adult humans and pigeons (Columbia livia).

Although geometric reorientation has been extensively studied in numerous species, most research has been conducted in enclosed environments and has focused on use of the geometric property of relative wall length. The current studies investigated how angular information is used by adult humans and pigeons to orient and find a goal in enclosures or arrays that did not provide relative wall length information. In enclosed conditions, the angles formed a diamond shape connected by walls, whereas in array conditions, free-standing angles defined the diamond shape. Adult humans and pigeons were trained to locate two geometrically equivalent corners, either the 60° or 120° angles. Blue feature panels were located in the goal corners so that participants could use either the features or the local angular information to orient. Subsequent tests in manipulated environments isolated the individual cues from training or placed them in conflict with one another. In both enclosed and array environments, humans and pigeons were able to orient when either the angles or the features from training were removed. On conflict tests, female, but not male, adult humans weighted features more heavily than angular geometry. For pigeons, angles were weighted more heavily than features for birds that were trained to go to acute corners, but no difference in weighting was seen for birds trained to go to obtuse corners. These conflict test results were not affected by environment type. A subsequent test with pigeons ruled out an interpretation based on exclusive use of a principal axis rather than angle. Overall, the results indicate that, for both adult humans and pigeons, angular amplitude is a salient orientation cue in both enclosures and arrays of free-standing angles.

Sources of systematic errors in human path integration.

Triangle completion is a task widely used to study human path integration, an important navigation method relying on idiothetic cues. Systematic biases (compression patterns in the inbound responses) have been well documented in human triangle completion. However, the sources of systematic biases remain controversial. We used cross-validation modeling to compare three plausible theoretical models that assume that systematic errors occur in the encoding outbound path solely (encoding-error model), executing the inbound responses solely (execution-error model), and both (bicomponent model), respectively. The data for cross-validation modeling are from a previous study (Qi et al., 2021), in which participants learned three objects' locations (one at the path origin, that is, home) very well before walking each outbound path and then pointed to the objects' original locations after walking the outbound path. The modeling algorithm used one inbound response (i.e., response to the home) or multiple inbound responses (i.e., responses to two nonhome locations and the home) for each outbound path. The algorithm of using multiple inbound responses demonstrated that the bicomponent model outperformed the other models in accounting for the systematic errors. This finding suggests that both encoding the outbound path and executing the inbound responses contribute to the systematic biases in human path integration. In addition, the results showed that the algorithm using only the home response could not distinguish among these 3 models, suggesting that the typical triangle-completion task with only the home response for each outbound path cannot determine the sources of the systematic biases. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Visual re-anchoring in misaligned local spaces impairs global path integration.

It is a prevailing theoretical claim that path integration is the primary means of developing global spatial representations. However, this claim is at odds with reported difficulty to develop global spatial representations of a multiscale environment using path integration. The current study tested a new hypothesis that locally similar but globally misaligned rooms interfere with path integration. In an immersive virtual environment, participants learned objects' locations in one room and then physically walked, while being blindfolded, to a neighboring room for testing. These rooms were rectangular but globally misaligned. Adopting different actual perspectives in the testing room, the participants judged relative directions (JRDs) from the imagined perspectives in the learning room. The imagined and actual perspectives were aligned or misaligned according to either local room structures or global cardinal directions. Prior to JRDs, participants did not conduct other tasks (Experiment 1) or judged relative global headings of the two rooms to activate global representations while seeing the testing room (Experiment 2) or in darkness (Experiment 3). Participants performed better at locally aligned than misaligned imagined perspectives in all experiments. Better performances for globally aligned imagined perspectives appeared only in Experiment 3. These results suggest that structurally similar but misaligned rooms interfered with updating global heading by path integration, and this interference occurred during but not after the activation of global representations. These findings help to settle the inconsistency between the theoretical claims and empirical evidence of the importance of path integration in developing global spatial memories. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The influence of environmental geometry and spatial symmetry on spatial updating during locomotion.

Spatial updating based on self-motion cues is important to navigation in the absence of familiar landmarks. Previous studies showed that spatial updating without vision was automatic. The goal of the current study was to investigate whether ambiguous orientations indicated by visual cues affect spatial updating based on self-motion. Participants learned an object array in a rectangular room. After the objects were removed, participants maintained their actual perspective or turned 180° to face opposite walls of the room. Participants judged relative directions from imagined perspectives based on the memories of the object array. The actual and imagined perspectives were aligned or misaligned. Better performance for aligned than misaligned perspectives (sensorimotor alignment effects) was used to indicate spontaneous updating of ones' headings relative to the object array. In Experiment 1, participants turned their bodies in the middle of the room so that their distances to the walls of the room looked similar before and after turning (spatial symmetry at the turning position with the rectangular room shape). In Experiments 2-3, participants turned their bodies in a location so that the distances to the facing walls looked different before and after turning (spatial asymmetry at the turning position with the rectangular room shape). The results showed sensorimotor alignment effects in Experiments 2-3 but not in Experiment 1. These results suggest that updating self-orientation based on self-motion was cancelled by ambiguous orientations indicated by spatial symmetry at the turning position, but not cancelled by ambiguous orientations indicated by the rectangular room shape per se. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Statistically Optimal Cue Integration During Human Spatial Navigation.

In 2007, Cheng and colleagues published their influential review wherein they analyzed the literature on spatial cue interaction during navigation through a Bayesian lens, and concluded that models of optimal cue integration often applied in psychophysical studies could explain cue interaction during navigation. Since then, numerous empirical investigations have been conducted to assess the degree to which human navigators are optimal when integrating multiple spatial cues during a variety of navigation-related tasks. In the current review, we discuss the literature on human cue integration during navigation that has been published since Cheng et al.'s original review. Evidence from most studies demonstrate optimal navigation behavior when humans are presented with multiple spatial cues. However, applications of optimal cue integration models vary in their underlying assumptions (e.g., uninformative priors and decision rules). Furthermore, cue integration behavior depends in part on the nature of the cues being integrated and the navigational task (e.g., homing versus non-home goal localization). We discuss the implications of these models and suggest directions for future research.

Developing global spatial memories by one-shot across-boundary navigation.

This study investigated to what extent people can develop global spatial representations of a multiroom environment through one-shot physical walking between rooms. In Experiment 1, the participants learned objects' locations in one room of an immersive virtual environment. They were blindfolded and led to walk to a testing position either within the same room (within-boundary) or in an adjacent novel room (across-boundary). They conducted judgments of relative direction (JRD) based on the remembered locations of objects. The participants' actual perspectives and imagined perspectives of JRD trials were manipulated to be aligned or misaligned (i.e., faced the same or opposite cardinal directions). The results showed better JRD performances for the aligned perspectives than the misaligned perspectives in the across-boundary condition; this global sensorimotor alignment effect was comparable with the effect in the within-boundary condition. Experiments 2-6 further examined global sensorimotor alignment effects after across-boundary walking. Experiments 2-3 manipulated factors related to encoding global relations (i.e., explicit instructions to attend to walking and keep track of spatial relations, and visual cues for navigational affordance to another space). Experiments 4-6 manipulated factors related to retrieving global relations in JRD (i.e., learning orientation as one imagined perspective, learning position and orientation as the imagined viewpoint, and the number of imagined perspectives). The results showed robust global sensorimotor alignment effects in all experiments, indicating that the participants updated actual headings relative to remembered objects in the other room. Global spatial updating might be the primary mechanism for developing global spatial representations of a multiscale environment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

When humans can fly: Imprecise vertical encoding in human 3D spatial navigation.

Previous research indicates that while animals who locomote on surfaces have a more variable and less precise spatial coding vertically than horizontally, animals who fly do not demonstrate a horizontal advantage (Hayman et al., 2011; Yartsev and Ulanovsky, 2013). The current study investigated whether humans' localization is more variable vertically than horizontally in different locomotion modes. In an immersive virtual room, participants learned the locations of objects presented on one wall. By locomoting from a location on the floor to each object, they replaced objects using memories. One group of participants (the flying group) flew three-dimensionally along their viewing direction by pushing a joystick. The second group (floor-wall group) locomoted only on the floor and the wall along the projection of the viewing direction onto the current travelling surface. The third group pressed a button to be teleported from the floor to the wall and then locomoted on the wall (wall-only group). The results showed that the variance of localization error was larger vertically than horizontally in the flying and floor-wall groups but that the pattern reversed in the wall-only group. In addition, while both the flying and wall-only groups locomoted straight towards the target location, the floor-wall group locomoted straight towards the projection of the target location onto the ground rather than straight towards the wall, indicating that the floor-wall group tried to avoid horizontal movement on the wall. These results suggest that for humans a horizontal advantage occurs in encoding the objects' locations presented on the wall whereas a vertical advantage occurs in locomotion on the wall.

Updating self-location by self-motion and visual cues in familiar multiscale spaces.

This study examined functions of self-motion and visual cues in updating people's actual headings in multiscale spaces. In an immersive virtual environment, the participants learned objects' locations inside two misaligned rectangular rooms by locomoting within and between the rooms. In each testing trial, the participants locomoted to adopt an actual perspective in one room, and then they judged relative direction to a target from an imagined perspective in the other room (remote perspective taking). The imagined and actual perspectives had the same or opposite cardinal directions (globally aligned or misaligned) or had the same or opposite orientations defined by room structures (locally aligned or misaligned). Global or local sensorimotor alignment effects mean that performance is better when imagined and actual perspectives were globally or locally aligned than when misaligned. We examined these effects to infer updating actual headings in global or local representations. The results showed local but no global sensorimotor alignment effect. By contrast, there were both global and local sensorimotor alignment effects when the participants judged across-room relative headings prior to remote perspective taking. These results indicate that people update headings in local representations based on visual similarities between local spaces. People update headings in global representations based on self-motion cues available in across-boundary navigation, but updating headings globally requires tasks to activate global-relevant sensorimotor representations. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Updating headings in 3D navigation.

This study investigated to what extent humans can encode spatial relations between different surfaces (i.e., floor, walls, and ceiling) in a three-dimensional (3D) space and extend their headings on the floor to other surfaces when locomoting to walls (pitch 90°) and the ceiling (pitch 180°). In immersive virtual reality environments, participants first learned a layout of objects on the ground. They then navigated to testing planes: south (or north) walls facing Up, or the ceiling via walls facing North (or South). Participants locomoted to the walls with pitch rotations indicated by visual and idiothetic cues (Experiment 1) and only by visual cues (Experiment 2) and to the ceiling with visual pitch rotations only (Experiment 3). Using the memory of objects' locations, they either reproduced the object layout on the testing plane or did a Judgements of Relative Direction (JRD) task ("imagine standing at object A, facing B, point to C") with imagined headings of south and north on the ground. The results showed that participants who locomoted onto the wall with idiothetic cues showed a better performance in JRD for an imagined heading from which their physical heading was extended (e.g., imagined heading of North at the north wall). In addition, the participants who reproduced the layout of objects on the ceiling from a perspective extended from the ground also showed a sensorimotor alignment effect predicted by an extended heading. These results indicate that humans encode spatial relations between different surfaces and extend headings via pitch rotations three-dimensionally, especially with idiothetic cues.

Cue combination in goal-oriented navigation.

This study examined cue combination of self-motion and landmark cues in goal-localisation. In an immersive virtual environment, before walking a two-leg path, participants learned the locations of three goal objects (one at the path origin, that is, home) and landmarks. After walking the path without seeing landmarks or goals, participants indicated the locations of the home and non-home goals in four conditions: (1) path integration only, (2) landmarks only, (3) both path integration and the landmarks, and (4) path integration and rotated landmarks. The ratio of the length between the testing position (P) and the turning point (T) over the length between the T and the three goals (G) (i.e., PT/TG) was manipulated. The results showed the cue combination consistently for participants' heading estimates but not for goal-localisation. In Experiments 1 and 2 (using distal landmarks), the cue combination for goal estimates appeared in a small length ratio (PT/TG = 0.5) but disappeared in a large length ratio (PT/TG = 2). In Experiments 3 and 4 (using proximal landmarks), while the cue combination disappeared for the home with a medium length ratio (PT/TG = 1), it appeared for the non-home goal with a large length ratio (PT/TG = 2) and only disappeared with a very large length ratio (PT/TG = 3). These findings are explained by a model stipulating that cue combination occurs in self-localisation (e.g., heading estimates), which leads to one estimate of the goal location; proximal landmarks produce another goal location estimate; these two goal estimates are then combined, which may only occur for non-home goals.

Effect of room size on geometry and features cue preference during reorientation: Modulating encoding strength or cue weighting.

Three experiments investigated how the room size affects preferential use of geometric and non-geometric cues during reorientation inside a room. We hypothesised that room size may affect preferential use of geometric and non-geometric cues by affecting the encoding of the cues (the encoding hypothesis), the retrieval of the cues (the retrieval hypothesis), or both the encoding and retrieval of the cues (the encoding-plus-retrieval hypothesis). In immersive virtual rectangular rooms, participants learned objects' locations with respect to geometric (room shape) and non-geometric cues (features on walls or isolated objects). During the test, participants localised objects with the geometric cue only, non-geometric cues only, or both. The two cues were placed at the original locations or displaced relative to each other (conflicting cues) when both were presented at testing. We manipulated the room size between participants within each experiment. The results showed that the room size affected cue preference using conflicting cues but did not affect response accuracy using single cues at testing. These results support the retrieval hypothesis. The results were discussed in terms of the effects of cue salience and stability on cue interaction in reorientation.

Developing global spatial representations through across-boundary navigation.

This study investigated the extent to which people can develop a global representation of local environments through across-boundary navigation. Participants learned objects' locations in two misaligned rectangular rooms in an immersive virtual environment. After learning, they adopted a local view in one room and judged directions of objects within the room; the views in two consecutive trials were from different rooms and locally or globally consistent (priming task). In some experiments, participants learned locations of five buildings before learning the objects in the rooms. In testing, after the priming task, they pointed to the buildings while adopting local views inside the rooms (across-boundary pointing task). Participants' estimated global headings were calculated from their pointing responses. The results showed that the priming effect from the globally consistent views occurred when participants learned the buildings and then locomoted between the rooms through a simple path. Consistent with the global priming effect, the means of participants' estimated global headings were accurate. In contrast, there was only the priming effect from the locally consistent views when participants did not learn the buildings before learning the objects inside the rooms or when participants were teleported between the rooms after learning the buildings. These results suggest that people can develop global representations of local environments through across-boundary navigation while traveling a simple path, provided that there are prior global representations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Cue combination used to update the navigator's self-localization, not the home location.

This study investigated when the Bayesian cue combination of piloting and path integration occurs in human homing behaviors. The Bayesian cue combination was hypothesized to occur in estimating the home location or self-localization. In Experiment 1, the participants learned the locations of 5 objects (1 located at the learning position) in the presence of distal landmarks before walking a 2-leg path without viewing the landmarks and objects. At the end of the path, the participants indicated the original locations of the objects in 4 cue conditions: (a) path integration only, (b) landmarks only where the participants were disoriented and the landmarks reappeared, (c) both path integration and the reappearing landmarks, and (d) path integration and conflicting landmarks rotated 45°. The participants' heading, position, and homing estimations were calculated. The ratio of the length of the second leg to that of the first leg was manipulated to be 0.5, 1, or 2. The results showed evidence of the Bayesian cue combination for heading estimates in all leg ratios, and for homing estimates in a small leg ratio (0.5) but not in a large leg ratio (2). The following experiments replicated the results of the Bayesian cue combination for heading but not for homing estimates for the large leg ratio (2) when participants did a typical homing task without learning the locations of objects (Experiment 2) and when proximal landmarks replaced distal landmarks (Experiments 3-4). These findings suggest that the Bayesian cue combination occurs in self-localization prior to homing. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Set size effects in spatial updating are independent of the online/offline updating strategy.

Spatial updating of self-to-object spatial relations may be performed online or offline. The set size effects in spatial updating are generally considered as a benchmark for indicating which updating strategy is used. Online updating is associated with transient egocentric representations and the presence of set size effects, whereas offline updating is associated with enduring allocentric representations and the absence of set size effects. In the present study, the updating strategy and the available spatial representations in updating were manipulated factorially. In a working memory (WM) paradigm, observers briefly learned a new layout of objects in each trial such that only the transient spatial representation was available during updating, whereas in a reference memory (RM) paradigm, observers learned the same layout of objects across trials such that both transient and enduring representations were available in updating. In both paradigms, observers were instructed to update online or offline. Set size effects showed up only in the WM paradigm but disappeared in the RM paradigm, regardless of the updating strategy. These results suggest that both updating strategies will produce set size effects if they use transient representations alone and that set size effects can be eliminated as long as enduring representations are used. These findings challenge the 2-system theories of spatial updating by showing that although online updating is naturally associated with transient spatial presentations, whereas offline updating is naturally associated with enduring representations, these default associations can be switched under manipulation. (PsycInfo Database Record (c) 2020 APA, all rights reserved).