Echolocation in humans: an overview

Abstract

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Visual sensory stimulation interferes with people’s ability to echolocate object size

“…It has long been established that certain species of bats and marine mammals use echolocation to navigate and locate prey 1 . Several studies have also demonstrated that humans are capable of using echolocation 2–4 . One of the most useful aspects of human echolocation is that it provides people a supplementary way of sensing their environment in low-vision conditions (e.g.…”

“…permanent or temporary blindness). For example, echolocation can be used to distinguish various properties of silent distal objects, such as shape, size, distance, location or movement 2–4 .…”

“…Neuroimaging research suggests that in blind echolocators it is not only auditory, but also visual areas, which are involved in the processing of echoes 4 . Comparison of brain activity, between echo-acoustic and control sounds, and between different types of echo-acoustic sounds, highlight the involvement of calcarine cortex when blind echolocators processed echo-acoustic information 11–15 .…”

Human echolocation - spatial resolution and signal properties

“…The waveform of a typical oral click can be described as a sinusoidal function modulated by a decaying exponential, although the exact nature of the oral click does vary between individuals and the procedure that they use to generate it. On average, a typical click (including the exponentially decaying tail of the waveform) can last up to 15 ms (Rojas et al, 2009) or be as short as 3 or 5 ms, with the number of clicks made varying between 1 and 5 per second and the typical sound level varying between 60 and 108 dB (Schörnich et al, 2012;Thaler & Goodale, 2016). In terms of the spectral content of these oral clicks, there is energy at multiple parts of the audible range, with peak frequencies typically between 2 and 8 kHz (Schörnich et al, 2012;Thaler & Castillo-Serrano, 2016), which is low compared to echolocating bats, who can produce emissions in the ultrasonic range (i.e.…”

Human echolocation: waveform analysis of tongue clicks

“…Participants showed accurate spatial localization and discrimination of objects with the same surface area but different shapes. These days more research has accumulated to suggest that echolocation may also give information about an object's distance and azimuth, shape, material, size and motion [5,6,9]. It has been suggested that the spectral composition of echoes may provide a vital source of environmental information [5,7,8].…”