The research shows that mammals developed the perceptive ability to focus on things seen as threatening, such as snakes and spiders, and to respond emotionally with a feeling of fear.
To reach their conclusions, Öhman and his colleagues conducted experiments in which their subjects were asked to identify pictures depicting sources of fear (snakes and spiders) from among an array of images that did not induce feelings of fear (mushrooms and flowers), and vice versa.
A statistically significant number of the subjects found the pictures of the snakes and spiders more quickly than they did those of mushrooms or flowers.
The scientists have tested out their virtual reality therapy on eight people with a phobia of spiders.
Before their journey into Spiderworld, most of these people were unable to come within five feet of a tarantula housed inside a glass cage.
After their experience, they were able to come within six inches of it.
Prior to treatment, Miss Muffet had been clinically phobic for nearly 20 years and had acquired a number of spider-related obsessive-compulsive behaviors. She routinely fumigated her car with pesticides and smoke to get rid of spiders. She sealed all bedroom windows with duct tape each night after scanning the room for spiders. She was hypervigilant, searching for spiders wherever she went, and avoiding walkways where she might find one. After washing her clothes, she immediately put her clothing inside a sealed plastic bag, to make sure it remained free of spiders.
Scientists figure humans may be born with a fear of spiders and snakes, healthy phobias that up the odds of survival in the wild. It's not known how such an inborn fear might develop, however.
Now researchers have proven that unborn crickets can gain a fear of spiders based on their mother's harrowing experiences.
McNally questions, for example, whether mammals really have evolutionary cause to be afraid of spiders. Only 0.1 percent of the 35,000 different kinds of spiders in the world are poisonous, he noted.
In a study conducted in the UK, it was found that 32% of females and 18% of males stated that spiders made them feel either anxious and nervous or very frightened.
Cognitive-behavioural therapy (CBT) is the standard clinical treatment for arachnophobia...Usually it involves some sort of exposure to spiders combined with ample moral support. The exposure is progressive and works towards a gradual desensitization using a series of spiders which are increasingly difficult for the patient to deal with.
Researchers asked people who had undergone therapy to address their fear of spiders to draw a line representing the length of a tarantula they had just encountered in a lab setting.
"On average, the most fearful were drawing lines about 50 percent longer than the least fearful," said Michael Vasey, lead study researcher and professor of psychology at Ohio State University. "We have seen participants draw lines that are at least three times as long as the actual spider."
According to this 'unclean' theory, arachnophobia may owe its origin to medieval Europe where the presence of spiders was associated with households infected by bubonic plague. The homes of the dead and dying fell into neglect and spiders moved in, acting as tell-tale signs of infection.
One of the first case report on the treatment of arachnophobia by means of immersive VR was published by Carlin, Hoffmann and Weghorst in 1997. The patient was a thirty-seven year old woman who suffered from a severe spider phobia. VRET treatment consisted in twelve weekly sessions of fifty-minute duration over three months, delivered by means of a VR system depicting a virtual kitchen seen through a head mounted display (HMD).