We've already seen interactive technologies that create smells or tactile sensations on command. Now, however, British scientists have developed a system that they claim can be used to make users experience specific emotions – and it does so without even touching the person.

Known as SenseX, the system incorporates existing UltraHaptics technology, which uses a phased array of ultrasonic emitters to produce steerable focal points of ultrasonic energy that provide sufficient radiation pressure to be felt by the skin. In other words, it gives the sensation of touching (or being touched by) an invisible object that's floating in midair.

Led by the University of Sussex's Dr. Marianna Obrist, the researchers started out with the knowledge that different emotions can be induced by touching different parts of a user's outstretched hand.

In order to see how that might apply to SenseX, they then got a group of test subjects to view five different images – calm scenery with trees, whitewater rafting, a cemetery, a burning car, and a clock on a wall – and then create UltraHaptics hand stimulations that reproduced the emotions that those images made them feel. They were free to adjust parameters such as the position, direction, frequency, intensity and duration of the ultrasonic stimulations.

A second group subsequently viewed the same images and got to feel all of the first group's stimulations, then chose the top two stimulations that they thought best produced the emotion captured by each image.

Finally, a third group got to see each image, each time sequentially feeling all 10 of the "best" stimulations as chosen by the second group (without knowing which stimulations went with which images). When they rated how effective the different stimulations were at creating the emotion suggested by each image, they gave the highest ratings to the stimulations that the second group had matched up with that image.

Obrist now believes that once developed further, SenseX could have various applications. These could include the ability to send wordless "emotion messages" to other people, to add an extra dimension to things like games and movies, or even to transmit a sense of excitement to the upraised hands of dancers at night clubs.

She is also looking at the senses of taste and smell, and how the stimulation of them could be worked into the technology.