From Duncan Butlin
Anil Ananthaswamy discusses an “invisible force field” surrounding humans (9 July, p 10). I believe there is a more important “field”: the effect of our presence on those around us.
The “peripersonal space” described exerts no force, whereas presence can affect everyone within eyesight, and hundreds simultaneously in a crowd. The force is transmitted mainly through posture, gesture and eye contact. A threatening stare, for example, challenges everyone within range. Denial is useless: one can forget one's own presence, but can never turn it off.
Chichester, West Sussex, UK
