Human fear of spiders draws scientific focus

Female comb-footed spider (family Theridiidae), Enoplognatha ovata. Photographed in the wild at DuPage County, Illinois, USA. Size = 15mm. Credit: Bruce Marlin/Wikipedia/CC BY 3.0

A fear of spiders, arachnophobia, is in our DNA. You don't learn to freeze at the site of these creatures; you're born with the fear. Even the sight of hypodermic needles and houseflies does not trigger a similar response. Scientists pin that fear on survival instinct. The theory goes like this: Humans evolved in Africa where being able to spot a spider was of necessity.

Some dangerous spider species may have been common during our . A number of species with potent venoms populated Africa before hominoids and have co-existed there for tens of millions of years. A bite in the ancestral world even if not fatal could leave one incapacitated for days or weeks.

Joshua New, Department of Psychology, Barnard College and colleague Tamsin German, wrote "Spiders at the cocktail party: an ancestral threat that surmounts inattentional blindness," which has been published in Evolution and Human Behavior. The paper stated that the human visual system may retain ancestral mechanisms uniquely dedicated to the rapid detection of immediate and specific threats, such as spiders and snakes, which persistently recurred throughout evolutionary time. The authors concluded that "Spiders may be one of a very few evolutionarily-persistent threats that are inherently specified for visual detection and uniquely 'prepared' to capture attention and awareness irrespective of any foreknowledge, personal importance, or task-relevance."

New and German asked their participants to look at abstract shapes and data on computer screens. Among those images were needles and flies. Results, as reported in the Daily Sun: "Of the 252 people reviewed in the study, most recognized the spiders much quicker than other images known to induce fear, such as flies and needles."

Spider images got more attention; the viewers spotted them and knew what they were. The authors reported that, "Despite their highly marginalized presentation, iconic spiders were nonetheless detected, localized, and identified by a very large proportion of observers."

Their test, said the authors, made use of the "inattentional blindness paradigm" in which an unexpected, peripheral stimulus is presented coincidentally with a central task-relevant display. Last year, Inside Science turned to the spider study which had been published online. Inside Science described how the study was designed: "To see if there is something special about spiders, the researchers showed people a cross shape that flashed in the middle of a screen for an eighth of a second. The participants' task, as far as they knew, was to judge which of the two bars on the cross was longer. During the first three trials, only the cross appeared. On the fourth trial, another image appeared at the same time. The possible images included a spider, a hypodermic needle, a housefly, and abstract shapes made by rearranging the lines of the spider."

People were asked if they saw anything other than just the cross and, if so, in which part of the screen. They also tried to identify the image by selecting it from a lineup.

New's study reflects a question that scientists have posed before about human reactions to spiders: In 2008, the study "Do infants possess an evolved spider-detection mechanism?" appeared in Cognition. Babies looked at spiders longer than they looked at other images. Authors David Rakison and Jaime Derringer talked about "an evolved predator recognition mechanism that specifies the appearance of recurring threats."

The results, they said, supported the hypothesis that humans "may possess a cognitive mechanism for detecting specific animals that were potentially harmful throughout evolutionary history."

Rakison said in Inside Science that "At least with children, there's very little conflicting evidence that and snakes have some kind of privileged nature in human visual processing."

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More information: Spiders at the cocktail party: an ancestral threat that surmounts inattentional blindness, Evolution and Human Behavior,

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Apr 06, 2015
I completely agree that human beings have some hard wired instinct to fear/hate spiders. I notice this around Halloween, when someone in my neighborhood puts out enormous wicker spiders in their front yard. I feel an innate urge to to destroy the damn things, every time I bike past. I know they are toy spiders, but each time I still have an urge to stomp and smash - it is completely beneath reason!

Apr 07, 2015
I do not fear spiders. We let some live in our house. If I find a large spider indoors, I carry it outside. Perhaps my genome is broken.

Apr 07, 2015
I suspect that we have adapted to "be aware of threats", rather than being afraid of any specific species of animal. This article smacks of VMAT2 being called the "god gene". Will we now find "the spider fear gene" or the "the snake fear gene"? The "fear of hypodermic needles" gene?

Apr 12, 2015
The theory goes like this: Humans evolved in Africa where being able to spot a spider was of necessity.

See also: "Isbell calls these findings "the first neuroscientific support" for her snake-centric evolutionary theory." http://news.scien...te-brain

As we wait for experimental evidence of biologically based cause and effect to support such ridiculous theories, it is important to reflect on their basis.

[W]hat Haldane, Fisher, Sewell Wright, Hardy, Weinberg et al. did was invent.... Evolution was defined as "changes in gene frequencies in natural populations." The accumulation of genetic mutations was touted to be enough to change one species to another.... Assumptions, made but not verified, were taught as fact. http://www.huffin...211.html

Apr 12, 2015
The paper stated that the human visual system may retain ancestral mechanisms uniquely dedicated to the rapid detection of immediate and specific threats, such as spiders and snakes, which persistently recurred throughout evolutionary time.

The paper was published online: August 20, 2014

Can anyone understand why this report on the findings was not published until April 6, 2015?
Could it be linked to this interview on the end of pseudoscientific nonsense that has been touted as evolutionary theory?

Beyond Genetic Evolution. A Conversation With Eva Jablonka

Excerpt: "Types do not have to be genotypes, they can be epigenotypes, behavioral types, symbolic types. If we agree on that broad definition, I don't see why change over time with respect to them is not evolution. Symbolic evolution is a very different type of evolution..."

Apr 13, 2015
mates, it's 2015, a long time since we decoded the Human DNA and we nly happen to have a very small amount of genes (32.000 if I reacall).
I remember that before that time it was very trendy to sway that anything that somebody came up with was in the genes, it was then calculated that we would need 180.000.000 of them.

So, now Aracnofobia is in the human genome. Nice. This means that Bolivians are not humans as I know many of them don't suffer from Arachnofobia... and I must be non-human too...

Does the same apply to Bats? I ask thsi beccuas I know a lot of people in the US have "bat-phobia" somethign that is practically unkown in good old Europe...

so, there may be different Human species after all?

Or is this study nothing but BS?

Apr 13, 2015 this study nothing but BS?

See: http://postgeneti...tic.html

Others may also want to see for information that integrates physics, chemistry, and molecular epigenetics.

Feedback loops link the nutrient-dependent physiology of reproduction to chromatin loops in the context of nutrient-dependent pheromone-controlled epigenetically-effected biodiversity.

See also: link to

Until you understand how biophysically constrained nutrient-dependent cell type differentiation occurs in the context of the physiology of reproduction and fixation of amino acid substitutions, you are likely to believe in any theory you are taught to believe in -- no matter how ridiculous it is. Spider-centric, bat-centric, and snake-centric theories are equally ridiculous, but some people are paid to study such things. Those people are called biologically uninformed.

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