In early 2017, American and Canadian diplomats in Cuba — and later tourists from both countries — reported hearing strange, high-pitched sounds in their hotel rooms. Then they started to experience strange neurological symptoms: speech problems, headaches, dizziness and mood disorders.
Secretary of State Rex Tillerson has said he is “convinced these were targeted attacks,” and Cuba has called the charges “science fiction.” This week, a group of electrical engineering professors at the University of Michigan and University of South Carolina proposed a simpler explanation in a new paper — that the ultrasonic signals from two eavesdropping devices interfered with one another, creating the piercing sound the travelers heard.
“In other words,” the researchers wrote in the paper, “acoustic interference without malicious intent to cause harm could have led to the audible sensations in Cuba.”
If so, it’s still not clear what would have led the tourists and diplomats to experience neurological symptoms that have persisted long after they left the country. Maybe the interference from the hypothetical two listening devices caused the injuries — but that’s unlikely, two of the researchers behind the paper wrote in a companion piece that ran in The Conversation, since there’s limited evidence that ultrasonic frequencies cause can cause lasting harm.
In the same article, they floated an alternative theory: that the tourists and diplomats heard the piercing sound, then convinced themselves they were experiencing symptoms in an episode of “mass hysteria.” While the cause of the symptoms is getting sorted out, whether there was intent behind them remains unclear.