Egocentric Cues Research Articles

Augmented reality in team-based search and rescue: Exploring spatial perspectives for enhanced navigation and collaboration

Indoor search and rescue (SAR) missions frequently encounter challenges due to complex spatial layouts and conditions of high stress. Augmented Reality (AR) has emerged as a promising tool to aid SAR efforts by offering spatial information through exocentric and egocentric perspectives. Specifically, AR systems introduce an egocentric perspective, overlaying detailed spatial information onto physical environments, which holds promise for navigating the complexities of indoor SAR operations. However, the effectiveness of these AR perspectives in a team-based SAR context remains underexplored. This study introduces a multi-user AR platform that combines reality capture with synchronized real-time spatial data and real-time cognitive load monitoring module to support team-based SAR missions. A human subject experiment (N = 64) was conducted with combined variations of spatial complexity and collaboration strategies to explore the efficacy of egocentric and exocentric navigation cues in aiding multi-agent SAR tasks. In the experiment, participants were asked to search for two consecutive targets while collaborating either parallelly, or hierarchically within a given time limit. Results indicated that egocentric cues offered limited benefits in a multi-agent setup, whereas exocentric cues notably increased team performance. Hierarchically structured teams resulted in fewer errors and improved efficiency during wayfinding tasks. Cognitive analysis revealed the importance of optimizing collaborative strategies to manage the mental demands of SAR missions instead of focusing on optimizing individuals. These findings contribute to understanding AR interface design’s complex role in multi-agent SAR support, aiming to improve AR system designs for SAR scenarios.

Hippocampal lesions impair non-navigational spatial memory in macaques.

Decades of studies robustly support a critical role for the hippocampus in spatial memory across a wide range of species. Hippocampal damage produces clear and consistent deficits in allocentric spatial memory that requires navigating through space in rodents, non-human primates, and humans. By contrast, damage to the hippocampus spares performance in most non-navigational spatial memory tasks-which can typically be resolved using egocentric cues. We previously found that transient inactivation of the hippocampus impairs performance in the Hamilton Search Task (HST), a self-ordered non-navigational spatial search task. A key question, however, still needs to be addressed. Acute, reversible inactivation of the hippocampus may have resulted in an impairment in the HST because this approach does not allow for neuroplastic compensation, may prevent the development of an alternative learning strategy, and/or may produce network-based effects that disrupt performance. We compared learning and performance on the HST in male rhesus macaques (six unoperated control animals and six animals that underwent excitotoxic lesions of the hippocampus). We found a significant impairment in animals with hippocampal lesions. While control animals improved in performance over the course of 45 days of training, performance in animals with hippocampal lesions remained at chance levels. The HST thus represents a sensitive assay for probing the integrity of the hippocampus in non-human primates. These data provide evidence demonstrating that the hippocampus is critical for this type of non-navigational spatial memory, and help to reconcile the many null findings previously reported.

Egocentric cues influence the allocentric spatial memory of object configurations for memory-guided actions.

Allocentric and egocentric reference frames are used to code the spatial position of action targets in reference to objects in the environment, i.e., relative to landmarks (allocentric), or the observer (egocentric). Previous research investigated reference frames in isolation, for example, by shifting landmarks relative to the target and asking participants to reach to the remembered target location. Systematic reaching errors were found in the direction of the landmark shift and used as a proxy for allocentric spatial coding. Here, we examined the interaction of both allocentric and egocentric reference frames by shifting the landmarks as well as the observer. We asked participants to encode a three-dimensional configuration of balls and to reproduce this configuration from memory after a short delay followed by a landmark or an observer shift. We also manipulated the number of landmarks to test its effect on the use of allocentric and egocentric reference frames. We found that participants were less accurate when reproducing the configuration of balls after an observer shift, which was reflected in larger configurational errors. In addition, an increase in the number of landmarks led to a stronger reliance on allocentric cues and a weaker contribution of egocentric cues. In sum, our results highlight the important role of egocentric cues for allocentric spatial coding in the context of memory-guided actions.NEW & NOTEWORTHY Objects in our environment are coded relative to each other (allocentrically) and are thought to serve as independent and reliable cues (landmarks) in the context of unreliable egocentric signals. Contrary to this assumption, we demonstrate that egocentric cues alter the allocentric spatial memory, which could reflect recently discovered interactions between allocentric and egocentric neural processing pathways. Furthermore, additional landmarks lead to a higher contribution of allocentric and a lower contribution of egocentric cues.

People Separate Allocentric and Egocentric Cues to Judge Orientation of their Surroundings and the Self

People Separate Allocentric and Egocentric Cues to Judge Orientation of their Surroundings and the Self

Allocentric spatial perception through vision and touch in sighted and blind children

Vision and touch play a critical role in spatial development, facilitating the acquisition of allocentric and egocentric frames of reference, respectively. Previous works have shown that children’s ability to adopt an allocentric frame of reference might be impaired by the absence of visual experience during growth. In the current work, we investigated whether visual deprivation also impairs the ability to shift from egocentric to allocentric frames of reference in a switching-perspective task performed in the visual and haptic domains. Children with and without visual impairments from 6 to 13 years of age were asked to visually (only sighted children) or haptically (blindfolded sighted children and blind children) explore and reproduce a spatial configuration of coins by assuming either an egocentric perspective or an allocentric perspective. Results indicated that temporary visual deprivation impaired the ability of blindfolded sighted children to switch from egocentric to allocentric perspective more in the haptic domain than in the visual domain. Moreover, results on visually impaired children indicated that blindness did not impair allocentric spatial coding in the haptic domain but rather affected the ability to rely on haptic egocentric cues in the switching-perspective task. Finally, our findings suggested that the total absence of vision might impair the development of an egocentric perspective in case of body midline-crossing targets.

Underwater Path Integration: Using the Celestial Dome to Get Back Home.

A new study shows that mantis shrimp employ path integration, based on celestial and egocentric cues as orientation references, to return to their underwater burrows.

The motor vertical in the absence of gravicentric cues

When participants are asked to flip an omnidirectional switch “down”, the direction of their responses depends mainly on gravicentric, less so on egocentric and least on visual cues about the vertical (Lackner and DiZio, Exp. Brain Res. 130:2−26, 2000). Here we evaluate response direction when gravicentric cues are not available. Participants flipped an omnidirectional switch “down” when gravito-inertial force acted orthogonally to the response plane on earth (session E), and when it was near zero during parabolic flights (session P). We found that the relative weight of visual cues was similar in both sessions, and it was similar to that in an earlier study where participants stood upright. Across all three data sets, the weight of visual cues averaged 0.09. The relative weight of egocentric cues was also similar in both sessions, averaging 0.87; however, it was significantly lower in the earlier study with upright participants, where it averaged 0.43. We further found that informative and noninformative tactile stimulation had no substantial effects on response direction, which suggests that the earlier reported anchoring effect of tactile signals for the perceived vertical may not extend to the motor vertical. We conclude that the absence of gravicentric cues is compensated by a higher weight of egocentric cues, but not by a higher weight of visual cues. As a consequence, astronauts, divers and persons who work on ground in a horizontal body posture may mishandle equipment because of their strong reliance on egocentric cues.

Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

During navigation, landmark processing is critical either for generating an allocentric-based cognitive map or in facilitating egocentric-based strategies. Increasing evidence from manipulation and single-unit recording studies has highlighted the role of the entorhinal cortex in processing landmarks. In particular, the lateral (LEC) and medial (MEC) sub-regions of the entorhinal cortex have been shown to attend to proximal and distal landmarks, respectively. Recent studies have identified a further dissociation in cue processing between the LEC and MEC based on spatial frames of reference. Neurons in the LEC preferentially encode egocentric cues while those in the MEC encode allocentric cues. In this study, we assessed the impact of disrupting the LEC on landmark-based spatial memory in both egocentric and allocentric reference frames. Animals that received excitotoxic lesions of the LEC were significantly impaired, relative to controls, on both egocentric and allocentric versions of an object–place association task. Notably, LEC lesioned animals performed at chance on the egocentric version but above chance on the allocentric version. There was no significant difference in performance between the two groups on an object recognition and spatial T-maze task. Taken together, these results indicate that the LEC plays a role in feature integration more broadly and in specifically processing spatial information within an egocentric reference frame.

Conveying spatial awareness cues in xR collaborations.

Spatial Augmented Reality (SAR) systems can be suitably combined with other existing Extended Reality (xR) technologies to support collaboration. In existing strategies, users unencumbered by a viewing technology, such as a tablet interface or a head-mounted display, must rely on the transmission of their collaborators' positioning through interpreting a first-person camera view. This design creates a seam between a user's experience of the augmented physical environment in SAR, and their collaborators' experience inside the virtual environment. To assist in development and evaluation of spatial cues to support spatial awareness in SAR environments, an egocentric spatial-communication taxonomy is presented given two determining dimensions, a cue's attachment (physical/virtual) and animation (local/world). We developed four egocentric cues which characterize the four independent dimensions of the matrix: arrow, path, glow, and radial, and a single exocentric world in miniature visualization. Our study shows that virtual attachment cues are preferred, providing the highest accuracy, highest performance when collaborators are occluded, and produce the least mental effort when used with a single virtual collaborator. For multiple collaborators however, the virtual attached, world animated radial cue produces significant increases in mental load and reductions in preference, demonstrating the impact of visual augmentation clutter. The single exocentric visualization produced higher levels of head movement, and poorer accuracy, however the novelty of the visualization produced positive qualitative results.

Reconsidering sex differences during place learning in túngara frogs.

In túngara frogs, female mate choice requires remembering the location and/or calls of preferred males who advertise from fixed positions within a breeding pond. A previous study found that, when solving a place discrimination task in the laboratory, female túngara frogs were able to learn a visual cue to solve the task, whereas males were not. In that task, male performance appeared to be inhibited, in part, by their attempt to use egocentric cues. We tested whether the sex difference in place learning previously reported would generalize to other training parameters with different cues available by eliminating the potential to use egocentric cues and increasing the number of trials per day. As before, frogs were given a choice between a red or yellow door, one of which led to shelters and return to their home cage. In the current testing conditions, we detected a preference for the red door; thus, we only considered frogs rewarded to the yellow door. Training was associated with an increase in correct choices and an increased preference for the yellow door. However, there was no evidence for a sex difference in learning. In summary, under the current training conditions, we found that the apparent female advantage in place learning was no longer evident. Future studies that investigate sex differences in cue preference and/or ability to switch among cues will further illuminate the conditions under which sex differences in learning are manifest in túngara frogs.

Egocentrically-stable discriminative stimulus-based spatial navigation in mice: implementation and comparison with allocentric cues

Animals are capable of using visual cues to find the correct route during navigation. These visual cues, which contain spatial information on the direction towards the goal point, are perceived either allocentrically or egocentrically. In this study, we examined how navigating with these two types of visual cues affects the learning processes of rodents. To present egocentrically-stable spatial cues, we devised a head-mounted device that provided discriminative orientation cues that indicated the correct choice at a fork within a double Y-maze. For allocentrically-stable spatial cues, LEDs serving as external route-mark cues were attached to the walls of the double Y-maze and illuminated to indicate the correct pathway. To rule out the possibility of the mice using extra-maze cues, we rotated the entire maze and used different start and goal sites for every trial. Our results revealed that mice using egocentric cues and external route-mark cues both showed a sigmoidal learning process for spatial navigation and that external route mark-based learning, surprisingly, learned faster than egocentric stimulus-based learning in egocentric space.

Response and place learning in crayfish spatial behavior.

Previous studies have demonstrated that animals use both environmental cues and egocentric information when orienting in mazes or nature. These two strategies have been examined separately in some species, yielding information on the specific properties associated with each. We examined spatial learning in crayfish (Orconectes rusticus) using an apparatus that required animals to orient under four different conditions: using egocentric (response) cues alone, response cues with inconsistent external (place) cues present, place cues with inconsistent response cues present, and place cues with consistent response cues present. Results demonstrated that crayfish could successfully learn a maze task using response cues alone and when external visual and tactile cues provided inconsistent information. Animals were markedly less successful at learning the task using place cues while disregarding inconsistent response information. We also found that more animals learned successfully when response and external cues were presented in a redundant format where both cues indicated the correct turn. Finally, we found that some crayfish were able to learn a single reversal when trained using response information alone and when response and external cues were presented in the redundant format. We consider these results in the light of findings from other species, and ideas on learning strategy properties, ecological relevance of strategies, and the possible role of stress coping style in crayfish learning.

The habitual motor vertical of humans depends on gravicentric and egocentric cues, but only little on visual cues.

Many studies have evaluated the interplay of gravicentric, egocentric, and visual cues for our perception of the vertical, but little is known about their interplay for motor control. Thirty-five participants flipped a switch "down" in experimental conditions which systematically varied body posture (upright; tilted 45° left-ear-down), visually indicated vertical (absent; aligned with the long body axis; rotated 45° counterclockwise with respect to the long body axis), and egocentric tactile information provided by a handhold (absent; present). Since we were interested in the participants' habitual rather than an instructed motor vertical, we did not specify which cues they should rely on. Our data revealed two response categories. Type-1 responses depended moderately on switch position; they relied mainly on gravicentric and egocentric cues, but only marginally on visual cues. Type-2 responses depended strongly on switch position; they relied on egocentric, but not on gravicentric or visual cues. We interpret the dependence on switch position as evidence that egocentric cues for type-2 responses may be anchored in the participants' arm rather than in their long body axis. In conclusion, the habitual motor vertical can vary when available cues are not aligned, and this variability can compromise manual performance of human operators.

Spatial midsession reversal learning in rats: Effects of egocentric Cue use and memory

The midsession reversal task has been used to investigate behavioral flexibility and cue use in non-human animals, with results indicating differences in the degree of control by environmental cues across species. For example, time-based control has been found in rats only when tested in a T-maze apparatus and under specific conditions in which position and orientation (i.e., egocentric) cues during the intertrial interval could not be used to aid performance. Other research in an operant setting has shown that rats often produce minimal errors around the reversal location, demonstrating response patterns similar to patterns exhibited by humans and primates in this task. The current study aimed to reduce, but not eliminate, the ability for rats to utilize egocentric cues by placing the response levers on the opposite wall of the chamber in relation to the pellet dispenser. Results showed that rats made minimal errors prior to the reversal, suggesting time-based cues were not controlling responses, and that they switched to the second correct stimulus within a few trials after the reversal event. Video recordings also revealed highly structured patterns of behavior by the majority of rats, which often differed depending on which response was reinforced. We interpret these findings as evidence that rats are adept at utilizing their own egocentric cues and that these cues, along with memory for the recent response-reinforcement contingencies, aid in maximizing reinforcement over the session.

Intraspecific variation in cue-specific learning in sticklebacks

Animals must identify reliable cues amidst environmental noise during learning, and the cues that are most reliable often depend on the local ecology. Comparing the performance of populations of the same species across multiple versions of a cognitive task can reveal whether some populations learn to use certain cues faster than others. Here, using a criterion-based protocol, we assessed whether two natural populations of sticklebacks differed in how quickly they learned to associate two different discrimination cues with the location of food. One version of the discrimination task required animals to use visual (colour) cues while the other required animals to use egocentric (side) cues. There were significant behavioural differences between the two populations, but no evidence that one population was generally better at learning, or that one version of the task was generally harder than the other. However, the two populations excelled on different tasks: fish from one population performed significantly better on the side version than they did on the colour version, while the opposite was observed in the other population. These results suggest that the two populations are equally capable of discrimination learning, but are primed to form associations with different cues. Ecological differences between the populations in environmental stability might account for the observed variation in learning. These findings highlight the value of comparing cognitive performance on different variations of the same task in order to understand variation in cognitive mechanisms.

Egocentric Temporal Action Proposals.

We present an approach to localize generic actions in egocentric videos, called temporal action proposals (TAPs), for accelerating the action recognition step. An egocentric TAP refers to a sequence of frames that may contain a generic action performed by the wearer of a head-mounted camera, e.g., taking a knife, spreading jam, pouring milk, or cutting carrots. Inspired by object proposals, this paper aims at generating a small number of TAPs, thereby replacing the popular sliding window strategy, for localizing all action events in the input video. To this end, we first propose to temporally segment the input video into action atoms, which are the smallest units that may contain an action. We then apply a hierarchical clustering algorithm with several egocentric cues to generate TAPs. Finally, we propose two actionness networks to score the likelihood of each TAP containing an action. The top ranked candidates are returned as output TAPs. Experimental results show that the proposed TAP detection framework performs significantly better than relevant approaches for egocentric action detection.

Egocentric Hand Detection Via Dynamic Region Growing

Egocentric videos, which mainly record the activities carried out by the users of wearable cameras, have drawn much research attention in recent years. Due to its lengthy content, a large number of ego-related applications have been developed to abstract the captured videos. As the users are accustomed to interacting with the target objects using their own hands, while their hands usually appear within their visual fields during the interaction, an egocentric hand detection step is involved in tasks like gesture recognition, action recognition, and social interaction understanding. In this work, we propose a dynamic region-growing approach for hand region detection in egocentric videos, by jointly considering hand-related motion and egocentric cues. We first determine seed regions that most likely belong to the hand, by analyzing the motion patterns across successive frames. The hand regions can then be located by extending from the seed regions, according to the scores computed for the adjacent superpixels. These scores are derived from four egocentric cues: contrast, location, position consistency, and appearance continuity. We discuss how to apply the proposed method in real-life scenarios, where multiple hands irregularly appear and disappear from the videos. Experimental results on public datasets show that the proposed method achieves superior performance compared with the state-of-the-art methods, especially in complicated scenarios.

Interplay of Gravicentric, Egocentric, and Visual Cues About the Vertical in the Control of Arm Movement Direction.

Our perception of the vertical corresponds to the weighted sum of gravicentric, egocentric, and visual cues. Here we evaluate the interplay of those cues not for the perceived but rather for the motor vertical. Participants were asked to flip an omnidirectional switch down while their egocentric vertical was dissociated from their visual-gravicentric vertical. Responses were directed mid-between the two verticals; specifically, the data suggest that the relative weight of congruent visual-gravicentric cues averages 0.62, and correspondingly, the relative weight of egocentric cues averages 0.38. We conclude that the interplay of visual-gravicentric cues with egocentric cues is similar for the motor and for the perceived vertical. Unexpectedly, we observed a consistent dependence of the motor vertical on hand position, possibly mediated by hand orientation or by spatial selective attention.

Sex differences during place learning in the túngara frog

The adaptive specialization hypothesis states that sex differences in cognition are shaped by differences in cognitive demands to solve ecological problems. While it is widely accepted that female mate choice can lead to the evolution of exaggerated male traits, mate choice might also select for different cognitive abilities in males and females. In the tungara frog, Physalaemus (= Engystomops) pustulosus, males call from a fixed position in breeding ponds while females visit multiple males before returning to the preferred mate. Thus, we predicted that females have better place memory than males. We tested this prediction in a place-learning task in which the rewarded arm of a maze was associated with a visual cue. We found that females were able to use the visual cue to solve the task while males were not, even though both males and females could discriminate the cues in an optomotor test. In contrast, males attempted to solve the task using egocentric cues (remember body-turn direction) in spite of the fact that our training procedure interrupted their use of such cues. Finally, we found that males and females had similar motivation to solve the task but females showed a greater ability to inhibit incorrect responses, leading to improved learning. Our finding that females could use a visual cue to remember locations in space is consistent with the idea that place memory could improve sequential mate assessment in tungara frogs.

Species differences in egocentric navigation: the effect of burrowing ecology on a spatial cognitive trait in mice

Efficient navigation is a critical component of fitness for most animals. While most species use a combination of allocentric (external) and egocentric (internal) cues to navigate through their environment, subterranean environments present a unique challenge in that visually mediated allocentric cues are unavailable. The relationship between egocentric spatial cognition and species differences in ecology is surprisingly understudied. We used a maze-learning task to test for differences in egocentric navigation between two closely related species of mice, the eastern house mouse, Mus musculus musculus, and the mound-building mouse, Mus spicilegus. The two species are sympatric in Eastern Europe and overlap in summer habitat use but differ dramatically in winter space use: whereas house mice occupy anthropogenic structures, mound-building mice survive the winter underground in intricate burrow systems. Given species differences in burrowing ecology, we predicted that M. spicilegus would learn the maze significantly faster than M. m. musculus when tested in complete darkness, a condition that eliminated allocentric spatial information and served as a proxy for the subterranean environment. We found strong support for this prediction. In contrast, the two species performed equally well when different mice were tested in the same maze with lights on. This context-specific species difference in spatial cognition suggests that enhanced egocentric navigation in M. spicilegus is an adaptation to the burrow systems on which the overwinter survival of young mound-building mice depends. The results of this study highlight the importance of ecological adaptations to the evolution of cognitive traits.