Arachnophobia is a fear of spiders. The term refers to the irrational fear of spiders. People have been fearful of these elusive insects since prehistoric times. However, recent research has found that the phenomenon may actually be more widespread than previously thought.
Several theories have been proposed to explain why humans are scared of spiders. Some of them include innate fear, learned behavior, and environmental factors.
One theory argues that humans were threatened by spiders in ancient times. Although they are less common in modern times, dangerous species of spiders are still present in South and Central America, Australia, and parts of Africa.
Another possible explanation is the evolutionary origin of arachnophobia. In the same way that tigers and crocodiles posed a threat to our ancestors, spiders could have been a threat at an early stage of our evolution.
However, most of these theories have failed to find concrete evidence. Recently, a study by Stefanie Hoehl and colleagues from the Max Planck Institute for Human Cognitive and Brain Sciences in Germany has found that spiders may have a significant influence on human behaviour.
Interestingly, the scientific research that produced this result was conducted on identical twins. These twins lived in different environments in their adult lives. This enabled scientists to study how their genes influenced their behaviour.
The results showed that the spider and snake images had the biggest impact on the test subjects. Their pupils also dilated by a large amount. For instance, the average pupil size was 0.14 mm larger for a snake image than for a spider image.