Fear of spiders is in our genes – we are programmed that way

Our fear of spiders – arachnophobia – has become part of our DNA as a product of human evolution since we first started walking on two legs in Africa millions of years ago. It is in our genes, two US researchers say.

Not everybody agrees with them. Some experts believe we become fearful of spiders as a result of social conditioning.

Assistant Professor Joshua New, who works in the Psychology Department at Barnard College, which is affiliated to Columbia University in New York, says that our ancient human ancestors in Africa who were able to spot spiders quickly would probably survive for longer in their environment than their less alert peers.

Fear of spiders

Do we acquire our fear of spiders, or are we genetically programmed that way? Experts disagree.

The Sunday Times quotes Prof. New, who said:

“A number of spider species with potent, vertebrate-specific venoms populated Africa long before hominoids – and have co-existed there for tens of millions of years. Humans were at perennial, unpredictable and significant risk of encountering highly venomous spiders in their ancestral environments.”


“Even when not fatal, a black widow spider bite in the ancestral world could leave one incapacitated for days or even weeks, terribly exposed to dangers.”

In a recent study, Professors Joshua New and Tamsin German, from the University of California at Santa Barbara, set out to determine how rapidly modern humans might spot a spider when presented with a number of different images simultaneously.

They wrote about their findings in the journal Evolution & Human Behavior.

Humans faster at spotting spiders than needles

Most of the 252 people who took part in the study recognized spiders much more rapidly than images of other nasty things that also induce fear, such as needles and flies.

In his website, Prof. New writes:

“This ability (to spot spiders rapidly) was highly specific to stimuli which conformed to a spider “template”: participants were frequently inattentionally blind to scrambled versions of the spider stimuli, and to a modern threat (hypodermic needle), and even a different animal (housefly).”

“This demonstrates that some evolutionary-relevant threats are highly-specified and can evoke what is perhaps best termed ‘reflexive awareness’: an immediate and elaborated perception sufficient to guide an adaptive behavioral response.”

It’s not due to nature, but nurture, says Prof. May

Professor of Psychology at the University of Plymouth in England, Jon May, believes we are not born with an inherent fear of spiders. He thinks we gradually acquire arachnophobia over the years, starting off during childhood when we see adults around us, older siblings and peers reacting in a certain way.

Fear of spiders learned

Prof. May believes we learn to become afraid of spiders by watching others around us from an early age.

Prof. May also points to certain spider features – dark colours, unpredictable movements, and angular legs – which make us more likely to be afraid of them.

Professor May says:

“Spiders just tick all these boxes, and like any phobia, when it builds up in someone’s mind they can become scared even seeing a picture.”

“We like bright-coloured butterflies and ladybirds, but spiders are dark coloured with long angular legs – and the shape and colour both have strong negative associations.”

“We are also very sensitive to seeing things moving out of the corner of our eye and immediately notice it, and insects move quickly and unpredictably.”

Prof. May suggests arachnophobia is the result of social conditioning, and not as Professors German and New suggest, because we are genetically programmed to react that way.

There were only 100 reliably reported deaths from spider bites globally in the 20th century, compared to about 1,500 from jellyfish bites. There are vastly more cases of arachnophobia, however, than of jelly fish phobia.

According to a European study, between 3.5% and 6.1% of the population suffer from arachnophobia.

Citation: Joshua J. New and Tamsin C. German. “Spiders at the cocktail party: an ancestral threat that surmounts inattentional blindness.” Evolution & Human Behavior. DOI: 10.1016/j.evolhumbehav.2014.08.004.