"When I started out," says David Levy, international chess champion and expert in artificial intelligence, "I didn't know anything about artificial vaginas.
Specifically, he read a quote from a 1984 book by Sherry Turkle, a professor at the Massachusetts Institute of Technology.
An interviewee, 'Anthony', told Turkle that he had tried having girlfriends but preferred his relationship with his computer.
"That quotation hit me like a brick wall," says Levy.
"I thought – if a smart guy could think like that in 1984, I wonder how much the concept of human-computer emotional relationships has developed since then." A great deal is the answer.
Adrian David Cheok, Professor of Pervasive Computing at London's City University, has been refining a device called a Kissinger: a set of pressure-sensitive artificial lips that can transmit a kiss from a real mouth to a similar device owned by a partner who might be thousands of miles away.
The Kissinger system has been in development for about eight years, with the latest model designed to plug into a smartphone.
By kissing the screen, the movements of a person's lips can be mirrored in the other machine and that kiss will be given to whoever has his or her mouth against a corresponding machine.
Several companies have shown an interest in the device and Cheok expects to see it hit the market in mid-2015.
Eventually, Cheok believes, "almost every physical thing, every being, every body, will be connected to the internet in some way.'' The future, he says, will involve the subconscious part of the brain.
We already have intimate data on the internet, but we still don't feel that we can really know somebody online.
There's something missing between the experience of making a Skype call and meeting someone.