Arachnophobia is a specific phobia brought about by the irrational fear of spiders and other arachnids such as scorpions. Signs and symptoms People with arachnophobia tend to feel uneasy in any area they believe could harbour spiders or that has visible signs of their presence, such as webs. If arachnophobes see a spider, they may not enter the general vicinity until they have overcome the panic attack that is often associated with their phobia. Some people scream, cry, have emotional outbursts, experience trouble breathing, sweat and experience increased heart rates when they come in contact with an area near spiders or their webs. In some extreme cases, even a picture, a toy, or a realistic drawing of a spider can trigger intense fear. Reasons Arachnophobia may be an exaggerated form of an instinctive response that helped early humans to survive or a cultural phenomenon that is most common in predominantly European societies. Evolutionary An evolutionary reason for the phobia remains unresolved. One view, especially held in evolutionary psychology, is that the presence of venomous spiders led to the evolution of a fear of spiders, or made acquisition of a fear of spiders especially easy. Like all traits, there is variability in the intensity of fear of spiders, and those with more intense fears are classified as phobic. Being relatively small, spiders do not fit the usual criterion for a threat in the animal kingdom where size is a factor, but they can have medically significant venom and/or cause skin irritation with their setae. However, a phobia is an irrational fear as opposed to a rational fear. By ensuring that their surroundings were free from spiders, arachnophobes would have had a reduced risk of being bitten in ancestral environments, giving them a slight advantage over non-arachnophobes in terms of survival. However, having a disproportionate fear of spiders in comparison to other, potentially dangerous creatures present during Homo sapiens environment of evolutionary adaptiveness may have had drawbacks. In The Handbook of the Emotions (1993), psychologist Arne Öhman studied pairing an unconditioned stimulus with evolutionarily-relevant fear-response neutral stimuli (snakes and spiders) versus evolutionarily-irrelevant fear-response neutral stimuli (mushrooms, flowers, physical representation of polyhedra, firearms, and electrical outlets) on human subjects and found that ophidiophobia (fear of snakes) and arachnophobia required only one pairing to develop a conditioned response while mycophobia, anthophobia, phobias of physical representations of polyhedra, firearms, and electrical outlets required multiple pairings