Your item on the phenomenon whereby appliances work perfectly in the presence of, but only in the presence of, a repair technician has caused me to wonder what endows this "techie" effect (Feedback, 15 January). As someone who uses computers more than my friends I found myself in increasing demand to help others, until at some point the techie effect cut in, and it needed only my presence to fix problems. What endowed that effect - was it perhaps the approach to the computer with no trace or scent of fear, and is it an attitude that suitable enlightenment training could pass on to the novice?

From Joanna Wojnar

Wolfgang Pauli was notorious for his ability to make experiments and equipment self-destruct, break or fail, simply by being in the vicinity. This has even been dubbed the "Pauli effect" (not to be confused with the Pauli exclusion principle). I propose therefore, that the curious situation of equipment functioning perfectly only in the presence of a qualified repair operative be termed "the reverse Pauli effect".

Wellington, New Zealand

From Alan Griffiths

You might like to know that in the theatre industry these sentient equipment faults tend to be known as SCUFs, or self-correcting unexplained faults. Lighting control desks and the tiny microphones that are clipped to a person's clothing are particularly prone to such naughtiness - although there is a theory that most SCUFs are in fact merely undisclosed pilot errors.

Malvern, Worcestershire, UK

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.