Arachnophobia even faint when they come in contact with an area near spiders or their webs. In some extreme cases, even a picture or a realistic drawing of a spider can trigger intense fear. 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. 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
Fear appeal finding that moderate to high levels of fear are unnecessary in changing intentions. In fact, they argue, what is important is the ratio of these to each other. Gore and Bracken (2005) found that even with low levels of threat, they were able to take individuals who had started to exhibit defensive fear control reactions to move toward danger control (intention change) reactions. Another way of defending yourself against fear appeals is prior knowledge, according to one study, individuals are less likely to be influenced by a fear appeal if they have prior knowledge. This is your brain on drugs,