Apple's iPhone 4S uses a female voice for its PA function in the US and a male voice in the UK. Why?

Siri, the digital PA on Apple's latest iPhone, is female in the US and male in the UK. Apple has declined to comment on the reasoning behind this, but theories abound.

Stephen Ebbett, of gadget insurer Protectyourbubble.com, says: "Apple has decided that Brits trust an authoritative male voice, while Americans traditionally favour and are more receptive to a female voice."

Last week, an editor at Washington-based Atlantic magazine, Rebecca Rosen, studied the gender politics of robots. She concluded that when technology uses a voice to guide us through phone messages or on public transport, it tends to be female. Anything more active or cerebral is usually male.

For manufacturers, working out the sex of technology is a complicated business – and one that unearths our prejudices. Professor Clifford Nass of Stanford University, an authority on the human-technology interface, said in the Toronto Star that people respond to robotic gender just as they do to human gender, with deeper voices considered "more intelligent and credible".

He worked at BMW in the 90s when it recalled navigation systems with a female voice: "Drivers [who were mostly male] didn't want to take directions from a female." So does the ubiquity of female GPS voices mean the situation has improved? Or is it because women's voices are thought to be more calming, reverting to the "women as carers, men as doers" paradigm?

Returning to Apple's Siri, Jeremy Wagstaff, who runs technology consultancy Loose Wire Organisation, says: "Americans speak loudly and clearly and are usually in a hurry, so it makes sense for them to have a female voice because it has the pitch and range. British people mumble and obey authority, so they need someone authoritative." Which, apparently, still means male.

• This article was amended on 21 October 2011. The original said the Atlantic magazine was based in Boston. This has been corrected.