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  • Author or Editor: Carlos dos Santos Luiz x
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It is known that moving visual stimuli (bouncing balls) have an advantage over static visual ones (flashes) in sensorimotor synchronization, such that the former match auditory beeps in driving synchronization while the latter do not. This occurs in beat-based synchronization but not in beat-based purely perceptual tasks, suggesting that the advantage is action-specific. The main goal of this study was to test the advantage of moving over static visual stimuli in a different perceptual timing system – duration-based perception – to determine whether the advantage is action-specific in a broad sense, i.e., if it excludes both beat-based and duration-based perception. We asked a group of participants to perform different tasks with three stimulus types: auditory beeps, visual bouncing balls (moving) and visual flashes (static). First, participants performed a duration-based perception task in which they judged whether intervals were speeding up or slowing down; then they did a synchronization task with isochronous sequences; finally, they performed a beat-based perception task in which they judged whether sequences sounded right or wrong. Bouncing balls outperformed flashes and matched beeps in synchronization. In the duration-based perceptual task, beeps, balls and flashes were equivalent, but in beat-based perception beeps outperformed balls and flashes. Our findings suggest that the advantage of moving over static visual stimuli is grounded on action rather than perception in a broad sense, in that it is absent in both beat-based and duration-based perception.

In: Timing & Time Perception

Summary

The Brazilian Amazon has the world’s largest concentration of indigenous American peoples, but many environmental threats have affected the preservation of this enormous human ethnocultural heritage. This study identified the species and studied the different uses of wood by two indigenous ethnic groups in Southeastern Pará, Brazil, namely the “Gavião” and “Suruí”. Ten taxa were identified, distributed in eight botanical families, with five being identified to genus and five to species levels. The wood of Bertholletia excelsa, an endangered forest species in Brazil, is important in the material culture of the Suruí indigenous people. The indigenous ethnic groups studied preferentially use medium density wood for building and high-density wood for hunting and warfare artefacts. The technological properties of wood justify its use by the indigenous peoples studied. We caution that the increasing environmental threats in Indigenous Lands within the Brazilian Amazon harm the preservation of the ethnocultural heritage of indigenous peoples.

In: IAWA Journal