Silence resulting from the cessation of movement signals danger

Six playback experimental designs fail to demonstrate acoustic preferences in common waxbills (Estrildidae: Estrilda astrild)

“…Waxbills are very gregarious and rarely found alone in nature, and the individuals used in our experiments had been kept in an aviary where they were permanently exposed to the activity and vocalizations of cage-mates. Therefore, the silence and absence of social cues during the experiments might contribute to stress experimental birds (e.g., Pereira et al, 2012). Nonetheless, replicating experiments with pairs of cage-mates, rather than birds alone, did not show behavioural preferences to playback stimuli, suggesting that social isolation was not the main cause for our results.…”

“…Based on sound quality, we selected one song from each of 18 different male waxbills, recorded from captured birds for experiments in previous years (2011 and2012;Cardoso et al, 2014). These recordings were made by placing a male waxbill singly in a cage next to a window, and recording its spontaneous singing with a digital video camera fixed at about 1.5 m distance.…”

Difficulties in Monitoring Conspecifics Mediate the Effects of Visual Obstruction on the Level and Synchronization of Vigilance

“…Use of auditory cues from a neighbor could also induce synchronization. Work with rats suggests that lack of feeding noises from a neighbor, which can be indicative of higher vigilance, is sufficient to induce vigilance in a visually isolated companion (Pereira et al, 2012). Vocal cues such as calls can also trigger vigilance adjustments in group members that are visually isolated (Radford and Ridley, 2007).…”

“…The above models suggest that visual cues are important although auditory cues, such as calls or sounds from neighbors, could also be used (Radford and Ridley, 2007;Pereira et al, 2012). Visual obstruction would thus be predicted to alter the ability to synchronize vigilance if visual cues are important when copying vigilance.…”

Pain-relief learning in flies, rats, and man: basic research and applied perspectives

“…If the subject registers an increased likelihood of threat in the preencounter phase, this results in increased general alertness, undirected search behavior, orienting, and risk assessment; this phase in humans is entangled with feelings of anxiety. The postencounter phase is characterized by freezing, reflex potentiation including startle, and selective attention to the encountered threat (interestingly, the silence that ensues upon the cessation of movement during freezing may, in turn, be a signal for threat to conspecifics [Pereira et al 2012], in particular in combination with ultrasonic distress vocalizations emitted into this silence [Wöhr and Schwarting 2013]). The strike phase is associated with directed fight/flight behavior; in humans both the postencounter and strike phase are characterized by the emotion of fear.…”