Recording of \"sonic attacks\" on U.S. diplomats in Cuba spectrally matches the echoing call of a Caribbean cricket

Abstract

Beginning in late 2016, diplomats posted to the United States embassy in Cuba began to experience unexplained health problems--including ear pain, tinnitus, vertigo, and cognitive difficulties1-4--which reportedly began after they heard1,2 strange noises in their homes or hotel rooms. In response, the U.S. government dramatically reduced1-3 the number of diplomats posted at the U.S. embassy in Havana. U.S. officials initially believed1,2,5 a sonic attack might be responsible for their ailments. The sound linked to these attacks, which has been described as a \"high-pitched beam of sound\", was recorded by U.S. personnel in Cuba and released by the Associated Press (AP). Because these recordings are the only available non-medical evidence of the sonic attacks, much attention has focused on identifying health problems6-11 and the origin12-17 of the acoustic signal. As shown here, the calling song of the Indies short-tailed cricket (Anurogryllus celerinictus) matches, in nuanced detail, the AP recording in duration, pulse repetition rate, power spectrum, pulse rate stability, and oscillations per pulse. The AP recording also exhibits frequency decay in individual pulses, a distinct acoustic signature of cricket sound production. While the temporal pulse structure in the recording is unlike any natural insect source, when the cricket call is played on a loudspeaker and recorded indoors, the interaction of reflected sound pulses yields a sound virtually indistinguishable from the AP sample. This provides strong evidence that an echoing cricket call, rather than a sonic attack or other technological device, is responsible for the sound in the released recording. Although the causes of the health problems reported by embassy personnel are beyond the scope of this paper, our findings highlight the need for more rigorous research into the source of these ailments, including the potential psychogenic effects, as well as possible physiological explanations unrelated to sonic attacks.