In times of high stress or effort, people sometimes feel the presence of others – an effect which isn't an hallucination. But what exactly is it? It was 2015 and Luke Robertson was skiing across Antarctica alone. There was nothing to see but vast expanses of snow and ice. Two weeks into a planned 40-day unsupported journey to the South Pole, he was behind schedule, feeling exhausted and demoralised. Then he looked up and to his left he saw… green fields. And not just any green fields, but the fields of his family's farm in Aberdeenshire, Scotland.

https://www.bbc.com/future/article/20230526-felt-presence-why-we-sometimes-feel-invisible-others

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