Teng, Santani · eScholarship (California Digital Library) · 2013
The use of active natural echolocation as a mobility aid for blind humans has received increased scientific and popular attention in recent years (Engber, 2006; Kreiser, 2006; NPR, 2011), in part due to a focus on several blind individuals who have developed remarkable expertise. However, perhaps surprisingly, the history of empirical human echolocation research is not much younger than the era of echolocation research (cf. Griffin, 1958). Nevertheless, compared to its bat and cetacean counterparts (Thomas et al., 2004), the field today remains in a state of comparative infancy. Until quite recently, nearly the entire body of human echolocation research has been behavioral in nature, with little insight into perceptual and neural mechanisms.Thus, the goal of this manuscript is to broadly integrate research findings in human echolocation across time, levels of analysis, and methodology. We will define human echolocation as it has been operationalized in research and practice, review behavioral goals served by echolocation, and identify putative auditory cues and neural mechanisms underpinning human echolocation. We examine some individual differences in echolocation performance, particularly involving blind compared to sighted persons. We present two studies in detail, addressing the spatial acuity of echolocation skills in sighted volunteers and blind experts. Throughout, we identify outstanding theoretical and applied questions that may form the basis for ongoing and future research. Taken together, we conclude that echolocation can serve behaviorally relevant perceptual goals; that spatial echolocation tasks such as size discrimination can be learned by sighted subjects, not just the blind; that the spatial resolution of echolocation can rival that of peripheral vision; that the variegated cues driving echolocation performance are processed at multiple levels of the auditory system; and that blindness likely plays an important role in shaping individual differences in echo processing.
Cited by 0Open access
Teng, Santani · eScholarship (California Digital Library) · 2013
The use of active natural echolocation as a mobility aid for blind humans has received increased scientific and popular attention in recent years (Engber, 2006; Kreiser, 2006; NPR, 2011), in part due to a focus on several blind individuals who have developed remarkable expertise. However, perhaps surprisingly, the history of empirical human echolocation research is not much younger than the era of echolocation research (cf. Griffin, 1958). Nevertheless, compared to its bat and cetacean counterparts (Thomas et al., 2004), the field today remains in a state of comparative infancy. Until quite recently, nearly the entire body of human echolocation research has been behavioral in nature, with little insight into perceptual and neural mechanisms.Thus, the goal of this manuscript is to broadly integrate research findings in human echolocation across time, levels of analysis, and methodology. We will define human echolocation as it has been operationalized in research and practice, review behavioral goals served by echolocation, and identify putative auditory cues and neural mechanisms underpinning human echolocation. We examine some individual differences in echolocation performance, particularly involving blind compared to sighted persons. We present two studies in detail, addressing the spatial acuity of echolocation skills in sighted volunteers and blind experts. Throughout, we identify outstanding theoretical and applied questions that may form the basis for ongoing and future research. Taken together, we conclude that echolocation can serve behaviorally relevant perceptual goals; that spatial echolocation tasks such as size discrimination can be learned by sighted subjects, not just the blind; that the spatial resolution of echolocation can rival that of peripheral vision; that the variegated cues driving echolocation performance are processed at multiple levels of the auditory system; and that blindness likely plays an important role in shaping individual differences in echo processing.
Cited by 0Open access
L. Thaler, S. R. Arnott, M. A. Goodale · Journal of Vision · 2010
It is common knowledge that animals such as bats and dolphins use echolocation to navigate the environment and/or to locate prey. It is less well known, however, that humans are capable of using echolocation as well. Here we present behavioral and fMRI data from two blind individuals (aged 27 and 45 years) who produce mouth-clicks and use click-based-echolocation to go about their everyday activities, which include walking through crowded streets in unknown environments, mountain biking, and other spatially demanding activities. Behavioral testing under regular conditions (i.e. in which each person actively produced clicks) showed that both individuals could resolve the angular position of an object placed in front of them with high accuracy (∼ 2° of auditory angle at a distance of 1.5 meters). This extremely high level of performance is remarkable, but not unexpected, given what they are capable of doing in everyday life. To validate the stimuli we planned to use in fMRI conditions, we took in-ear audio recordings from each individual during active echolocation and played those recordings back using MRI compatible earphones. In these conditions, both individuals were still able to use echolocation to determine with considerable accuracy the angular position, shape (concave vs. flat), motion (stationary vs. moving), and identity (car vs. tree vs. streetlight) of objects. Importantly, during the recordings, none of the objects emitted any sound but simply offered a sound-reflecting surface. We conclude that echolocation, during both active production and passive listening, enables our two participants to perform tasks that are typically considered impossible without vision. To investigate the neural substrates of their echolocation abilities, we employed our passive listening paradigm in combination with fMRI (see Abstract ‘Human Echolocation II’).
Cited by 5Open access
Sven Schörnich, Ludwig Wallmeier, Nikodemus Geßele et al. · Advances in experimental medicine and biology · 2013
Cited by 16
Simon Makin · Nature · 2025
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Tirado Aldana, Carlos · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2021
Echolocation is the capacity to detect, localize, discriminate, and, overall, gather spatial information from sound reflections. Since we began studying it in humans, we have learned several things. First, most humans can echolocate to some degree. Second, the capacity to echolocate is related to: the type and size of the object that the individual is trying to echolocate; how well the individual can use self-generated or artificial signals; and the distance to the object. Third, the blind tend to perform better than the sighted, although some sighted individuals can perform as well as the blind. It has been speculated that expert echolocators are capable of unlearning the precedence effect (PE), which is the tendency of our auditory system to prioritize spatial information coming from the first wave front instead of the spatial information from the second wave front. This would allow them to obtain more spatial information from echoes, but there is little research linking the PE to echolocation skills, which is why my thesis research has explored this matter. Another contribution of my thesis research was to introduce two new concepts: echo-detection and echo-localization. Echo-detection is the ability to detect an object using echoes as the main cue (“Is the object there, yes or no?”), whereas echo-localization is the ability both to detect and also localize an object using echoes as the main cue (“Is the object situated to the right or left?”). The reason for dividing echolocation into these two tasks is that detecting an echo does not necessarily entail knowing its location. No previous study has compared these two distinct abilities. Echo-detection and echo-localization, though linked to each other, could be influenced by different mechanisms. The aim of this thesis was to explore individual differences in echo-detection, echo-localization, and other fundamental psychoacoustic abilities (i.e., PE and different types of masking) in inexperienced, sighted individuals. This included using a novel tool to train and assess echolocation skills: the Echobot. The Echobot is a machine that automates stimulus presentation. It allows an aluminum disk to be moved to different distances and different echolocation signals to be tested simultaneously. Its main advantage consists of facilitating the use of rigorous psychophysical methods that would otherwise take a long time to perform correctly. Studies I and II focused on individual differences in fundamental hearing abilities that are prerequisites for echo-detection and echo-localization (i.e., PE components and different types of masking). Studies III and IV focused on using the Echobot to study individual performance differences in echo-detection and echo-localization tasks. Overall, the results indicate that echolocation was possible for most participants, regardless of the method or signal used. There were substantial individual differences, and a performance gap between echo-detection and echo-localization appeared in several individuals. Echo-localization was usually more difficult than echo-detection, since spatial information was the hardest to retrieve from the localization tasks. It was possible to close the task performance gap in some individuals through training, but only for time intervals between direct and reflected sound of >20 ms, for which the PE might not operate. Hence, the possibility of “unlearning” the PE to improve echolocation skills remains speculative. Finally, the Echobot proved useful for studying echolocation. Taken together, these results suggest that independent mechanisms make the localization of spatial information more difficult than pure detection. However, in long-inter-click-interval (ICI) conditions, the neural mechanisms are likely mediated by attention and cognitive processes, which are more plastic, and participants can learn to obtain echo-localization information as effectively as echo-detection information. In short-ICI conditions, neural mechanisms seem more related to peripheral and temporal processing, which are potentially less plastic. Further research into individual differences in temporal processing, using brain-imaging techniques such as EEG, might help us understand the different mechanisms influencing echo-detection and echo-localization.
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T. Claire Davies · Library and Archives Canada (Government of Canada) · 2008
Individuals with functional blindness must often utilise assistive aids to enable them to complete tasks of daily living. One of these tasks, locomotion, poses considerable risk. The long white cane is often used to perform haptic exploration, but cannot detect obstacles that are not ground-based. Although devices have been developed to provide information above waist height, these do not provide auditory interfaces that are easy to learn. Development of such devices should adapt to the user, not require adaptation by the user. Can obstacle avoidance be achieved through direct perception? This research presents an auditory interface that has been designed with the user as the primary focus. An analysis of the tasks required has been taken into account resulting in an interface that audifies ultrasound. Audification provides intuitive information to the user to enable perceptive response to environmental obstacles. A device was developed that provides Doppler shift signals that are audible as a result of intentional aliasing. This system provides acoustic flow that is evident upon initiation of travel and has been shown to be effective in perceiving apertures and avoiding environmental obstacles. The orientation of receivers on this device was also examined, resulting in better distance perception and centreline accuracy when oriented outward as compared to forward. The design of this novel user interface for visually impaired individuals has also provided a tool that can be used to evaluate direct perception and acoustic flow in a manner that has never been studied before.
Cited by 2
H. Watanabe, Miwa Sumiya, Tsutomu Terada · IEEE Access · 2022
Echolocation has been shown to improve the independence of visually impaired people, and using ultrasound in echolocation has more advantages, e.g., higher resolution of object sensing and ease of extraction from background sounds. However, humans cannot make and hear the ultrasound by their original ability. A wearable device enables ultrasonic echolocation, i.e., transmitting ultrasound by an ultrasonic speaker and converting the reflected ultrasound into audible sound. At the same time, the system can recognize the objects using machine learning (ML) and assist the user. Therefore, in this paper, we propose cooperative echolocation that combines the recognition by humans and ML. As the first step toward cooperative echolocation, this paper presents the effectiveness of ML in echolocation. We implemented a prototype device and evaluated the performance of object detection with/without ML. The results showed that the required time for object detection was reduced by 35.8% and the mental workload was significantly decreased by ML. Based on the findings from the evaluation, we discussed the design of cooperative echolocation.
Cited by 1Open access
Jascha Sohl‐Dickstein, Santani Teng, Benjamin M. Gaub et al. · IEEE Transactions on Biomedical Engineering · 2015
Interpreting and interacting with the external world constitutes a major challenge for persons who are blind or visually impaired. This device has the potential to aid blind people in interacting with their environment.
Cited by 56Open access
Romeiro, Gustavo da Silva Correa · Open Repository of the University of Porto (University of Porto) · 2021
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Lore Thaler, Stephen R. Arnott, Melvyn A. Goodale · PLoS ONE · 2011
These findings suggest that processing of click-echoes recruits brain regions typically devoted to vision rather than audition in both early and late blind echolocation experts.
Cited by 321Open access
Rick de Vos, Maarten Hornikx · Figshare · 2017
This collection includes a dataset the sound directivity of six different tongue clicks that are produced for human echolocation puposes, as well as the MATLAB code that is used to retreive different acoustic properties of tongue clicks. <br>The methodology is described in the technical journal paper 'Acoustic Properties of Tongue Clicks', submitted to Acta Acustica United with Acustica, by Rick de Vos and Maarten Hornikx.
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Virginia L. Flanagin, Sven Schörnich, Michael Schranner et al. · Journal of Neuroscience · 2017
Some blind humans have developed echolocation, as a method of navigation in space. Echolocation is a truly active sense because subjects analyze echoes of dedicated, self-generated sounds to assess space around them. Using a special virtual space technique, we assess how humans perceive enclosed spaces through echolocation, thereby revealing the interplay between sensory and vocal-motor neural activity while humans perform this task. Sighted subjects were trained to detect small changes in virtual-room size analyzing real-time generated echoes of their vocalizations. Individual differences in performance were related to the type and number of vocalizations produced. We then asked subjects to estimate virtual-room size with either active or passive sounds while measuring their brain activity with fMRI. Subjects were better at estimating room size when actively vocalizing. This was reflected in the hemodynamic activity of vocal-motor cortices, even after individual motor and sensory components were removed. Activity in these areas also varied with perceived room size, although the vocal-motor output was unchanged. In addition, thalamic and auditory-midbrain activity was correlated with perceived room size; a likely result of top-down auditory pathways for human echolocation, comparable with those described in echolocating bats. Our data provide evidence that human echolocation is supported by active sensing, both behaviorally and in terms of brain activity. The neural sensory-motor coupling complements the fundamental acoustic motor-sensory coupling via the environment in echolocation.<b>SIGNIFICANCE STATEMENT</b> Passive listening is the predominant method for examining brain activity during echolocation, the auditory analysis of self-generated sounds. We show that sighted humans perform better when they actively vocalize than during passive listening. Correspondingly, vocal motor and cerebellar activity is greater during active echolocation than vocalization alone. Motor and subcortical auditory brain activity covaries with the auditory percept, although motor output is unchanged. Our results reveal behaviorally relevant neural sensory-motor coupling during echolocation.
Cited by 72Open access
Haydee Garcia-Lazaro, Pushpita Bhattacharyya, Brendyn Chao et al. · Journal of Vision · 2024
Echolocation is an active sensing strategy used by some blind individuals to navigate their surroundings. Human echolocators emit tongue clicks, leveraging the echoes to detect, discriminate, and localize objects within their environment. Proficient blind echolocators outperform non-expert blind and sighted individuals in most echo-acoustic tasks; while visual experience and expertise play significant roles in echolocation performance, the underlying mechanisms of this advantage remain unclear. Recent research from our lab suggests that the emitted click masks the subsequent fainter echo, and superior performance among experts may be attributed to a more effective release from masking relative to novices. We explore this hypothesis by evaluating the influence of two aspects of masking on echolocation performance: click-echo signal-to-noise ratio (SNR) and click-echo temporal separation. Novice-sighted individuals completed an echo-acoustic localization task. Each trial consisted of 2, 5, 8, or 11 synthesized mouth clicks with spatialized echoes from reflectors 1-meter away and 5°–25° from the midsagittal plane. Participants indicated the reflector’s location (left vs. right). In Experiment 1, the click amplitude was variably attenuated relative to its natural amplitude. In Experiment 2, click amplitude was fixed while the click-echo time delay varied from ~6–60 ms, equivalent to 1–10 meters. We hypothesized that performance would improve as click-echo amplitude attenuates (Exp. 1) and click-echo time delay increases (Exp. 2). Our results revealed that novice-sighted individuals, at echo-click-level-difference > -2 dB or click-echo time delay > 52 ms, performed similarly to proficient echolocators presented with naturalistic stimuli (~25 dB; ~6 ms). These findings suggest that a well-tuned click-echo relationship, alongside an optimized click-echo temporal integration window, enhances echolocation performance. Future research will explore their combined or separate roles in auditory filters. Finely tuned click-echo SNRs and a narrower click-echo temporal integration window may underlie echolocation proficiency due to improved click-echo segregation and echo representation.
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Vos, Rick De, Hornikx, Maarten · Figshare · 2016
This collection includes a dataset the sound directivity of six different tongue clicks that are produced for human echolocation puposes, as well as the MATLAB code that is used to retreive different acoustic properties of tongue clicks. <br>The methodology is described in the technical journal paper 'Acoustic Properties of Tongue Clicks', submitted to Acta Acustica United with Acustica, by Rick de Vos and Maarten Hornikx.
Cited by 0Open access
Bo N. Schenkman, Mats E. Nilsson, Nedelko Grbić · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2011
Blind people may detect objects from the information in reflected sounds, echolocation. Detection as a function of the number of clicks compared to a continuous noise was tested by presenting clicks of 5 ms with rates from 1 to 64 clicks during a 500 ms period and a 500-ms continuous white noise. The sounds were recorded in an ordinary room through an artificial binaural head. The reflecting object was an aluminum disk, diameter 0.5 m, at distances of 1 and 1.5 m. These sounds were later presented to 3 blind and 16 sighted participants in a laboratory using a 2AFC methodology. The task was to detect which of the two sounds that contained a reflecting object. Feedback was provided. The blind participants had a higher detection than the sighted, but there were also differences among the blind. These results are put in relation to physical features such as the autocorrelation function and spectral variations. Blind people use sounds to find out how the world around them is constituted. One source of information is the direct sounds emitted by sound sources
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Shunsuke Uchibori, Masataka Kinoshita, Kaoru Ashihara et al. · The Journal of the Acoustical Society of America · 2013
To promote understanding of sonar mechanisms in bats, we propose a novel tool that makes echolocation available for humans. In this method, ultrasonic echoes are captured by a miniature dummy head so that they can be converted to binaural audible sounds using time expansion.In order to examine the effectiveness of this technique, perceptual listening tests were conducted on human listeners with normal hearing.The sounds (white noise with frequencies between 5 and 90 kHz with 0.7-s duration, including 0.05-s rise/fall time) were recorded at a distance of 1 m from a loudspeaker using two condenser microphones that were placed in the ear canals of a 1/7 size miniature dummy head. The recorded ultrasounds were 1/7-times pitch converted, and then were presented to the listener through headphones. As a result, the listeners perceived correct directions of the pitch converted sounds, which were recorded using the miniature dummy head, although front-back error was occasionally observed. When the miniature dummy head was rotated during the recording, the listeners perceived the movement of the sounds as out-of-head sound localization. The miniature dummy head may provide humans with a tool to understand biosonar mechanisms.
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Gavin Buckingham, Jennifer L. Milne, Caitlin M. Byrne et al. · Psychological Science · 2014
Certain blind individuals have learned to interpret the echoes of self-generated sounds to perceive the structure of objects in their environment. The current work examined how far the influence of this unique form of sensory substitution extends by testing whether echolocation-induced representations of object size could influence weight perception. A small group of echolocation experts made tongue clicks or finger snaps toward cubes of varying sizes and weights before lifting them. These echolocators experienced a robust size-weight illusion. This experiment provides the first demonstration of a sensory substitution technique whereby the substituted sense influences the conscious perception through an intact sense.
Cited by 33Open access
Chacin, Aisen Carolina, 194511 · Terrestrial Environment Research Center (University of Tsukuba) · 2018
Cited by 0Open access
Lore Thaler · Durham Research Online (Durham University) · 2015
Cited by 2Open access