Spooky costumes are all well and good, but if you really want to scare the living daylights out of someone, technology can certainly help. Here's a round-up of stuff that might come in handy this Halloween?
Harness the 'uncanny valley'
One way to give someone the heebie-jeebies could be to send them into the uncanny valley. This phrase defines the unnerving feeling that occurs when something looks and acts much like a human, but quite clearly isn't. It's a phenomenon particularly associated with unnervingly lifelike robots and, looking at this "robotic child" CB2 (below), it's not hard to see why.
CB2's odd skin gives it tactile capabilities, but combined with some disturbingly realistic behaviour, its weird appearance is also enough to give anyone bad dreams.
While less bizarre than CB2, Aactroid ? a robot designed to work as an office receptionist ? is still realistic enough to give someone the creeps.
Brain imaging experiments carried out by researchers at University College London could help explain why such human-like technologies naturally invoke a feeling of uneasiness in people. Thierry Chaminade and Ayse Saygin at UCL speculate that this reaction may have an evolutionary explanation ? helping people to identify individuals who may be carrying an infectious disease. Whatever the explanation, it could be a useful trick for spooking out guests at a Halloween party.
There are other ways robots can tap into a person's primal fears, by impersonating other things that invoke a sense of dread ? insects, snakes and spiders, for example.
The six-legged robot below might have a remarkable ability to climb walls and trees, but its insect-like movement are also likely to trigger feeling of unease.
Another video clip shows a beetle-like robot crawling through a stretch of intestine. It could one day perform life-saving stomach surgery, but it also looks worryingly like something out of a science-fiction movie. Or how about a robot that needs to consume living insects just to keep going. The stuff of nightmares indeed.
Get inside the brain
This is all well and good, but if you really want to terrify someone, perhaps it's best to tap directly into the fear centres in their brain.
Last year, theme-park rides equipped with EEG and heart-rate monitors for each user were installed at Science Museum in London. The idea was to measure sense of excitement and fear felt by those being flung through the air. But equally the information could be used to create the most terrifying roller coaster imaginable.
Computerised optical illusion are another scary way to play with someone's brain. Here are some neat examples of tricks used by Swiss and UK researchers to induce out-of-body experiences in subjects. Computer software might also provide the perfect Halloween costume by changing your skin to something much weirder.
Similarly, information gleaned from experiments with video games could prove useful for working out how best to be scary. Another team of researchers at UCL built a version of Pac-Man that delivers an electric shock when the player gets caught by a ghost. It's an interesting exploration of the way fear affects the brain, but the same information could be used to train a game to scare the pants of its player, by identifying what makes them most afraid and springing surprises when they least expect them.
Once the perfect moment has been chosen, a direct approach would be to deliver a huge magnetic pulse to someone's brain, an approach pioneered, with terrifying results by Michael Persinger, a neuro-scientist at Laurentian University at Sudbury in Ontario, Canada, who used his "god helmet" to investigate into the nature mystical and psychic experiences.
If you want to get more, this paper from Nature describes experiments that involved inducing the disturbing sensation of someone standing nearby by stimulating the left hemisphere of the brain. French, Swiss and US researchers discovered the trick while preparing a patient for treatment for epilepsy, and it resembles experiences reported by numerous psychiatric and neurological patients. Oh, and it's worth noting that research has shown that the dark really does make people people more fearful.
So, based on the evidence above, the ultimate way to terrify someone must be to place them on a particularly scary roller coaster, next to an unnervingly realistic robot, in the dark, while wearing the "god helmet". Of course, I wouldn't recommend actually doing any of that while you're out trick-or-treating, though. Will Knight, online technology editor
Posted by Will Knight, online technology editor at 5:27 PM