Phobias and fears may be passed down from the memories and experiences of one’s ancestors. This is the new finding from a team at Emory University School of Medicine in Atlanta. Seemingly irrational phobias might therefore be something individuals are born with.
The assumption has long been held that it is during the course of a lifetime that persons accrue their own memory bank and the only way to pass this on is to teach it. Now this theory is turned on its head by the discovery that learned experience can be biologically inherited.
Arachnophobia, fear of spiders, might date back hundreds of years to an ancestor’s frightening encounter and have nothing to do with personal inexplicable panic attack at the sight of a Daddy-Long-Legs. It’s a defence mechanism, encoded into the DNA by chemical changes. So says Brian Davis from Emory who sums it up neatly as “ancestral experience before conception.”
Results of the study have been published in Nature Neuroscience journal. The authors claim that the transmission of intergenerational worries may well contribute to the risk of neuropsychiatric disorders. Among these would be phobias, anxiety attacks and even post-traumatic stress disorders.
Mice were used to collect the data. They were trained to dislike the smell of cherry-blossom. They became extremely fearful when they encountered the aroma for the first time. The mice were then bred, and the next generation exhibited the exact same fear of cherry-blossom. The brains of the mice showed structural change and their DNA carried epigenetic methylation, the chemical, on the gene that was employed in odour identification.
Now that they know it definitely occurs, the next step is to figure out how that information gets to be stored on the DNA. Paediatric geneticist at University College London, professor Marcus Pembrey, said that the study had revealed “compelling evidence” that memory can be biologically transmitted. Pembrey added, “I suspect we will not understand the rise in neuropsychiatric disorders or obesity, diabetes and metabolic disruptions generally without taking a multigenerational approach.”
Cornell University has also been conducting work on mice and memory. Dr Miklos Toth has found that chemokines, or immune system factors, in the mother’s milk, affects the strength of mice spatial memory as they get older. The milk has a direct effect on hippocampal development, which is the seat of memory.
Joining up these new researches may take some time. The head of epigenetics at The Babraham Institute in Cambridge, Professor Wolf Reik, said the results were all encouraging. “They suggest that transgenerational inheritance exists and is mediated by epigenetics.” He hopes to see more study done with animal models before extrapolating any findings onto the human population.
Phobia-sufferers may be relieved to think there is some logical basis for their crippling fears and anxieties. Some more modern phobias, such as a fear of flying, may appear difficult to blame on an ancestor lost in the mists of times. Which ancient experience may have spawned such fright? Maybe they were chased to the edge of a cliff by a dinosaur? One of the newest phobias is nomophobia, a fear of not having a mobile phone. Again, one has to employ imagination to provide a scenario for an ancestor here. Perhaps the fire going out and the inability to send smoke signals?
The torments of phobia are many and varied. Some of them are highly unusual:
Turophobia is the fear of cheese. Coulrophobia, quite a common one, is fear of clowns. Johnny Depp, a famous sufferer from coulrophobia puts it down to their painted on smiles, it’s impossible, says Depp, to tell if “they are happy or if they are about to bite your face off.”
Omphalophobia, rather less common, is fear of the navel. This bellybutton aversion is usually linked to the idea of its being the link to the umbilical cord and the womb. Pogonophobia is fear of beards. Ombrophobia, fear of rain. Xanthophobia, fear of the color yellow. Somniphobia, fear of going to sleep.
Some phobias have not yet been recognised as official, although one of these, Trypophobia, is reportedly endured by thousands. It the fear of objects with small holes in them, like sponges. While some phobias sound obscure, they are certainly not so for those who have to endure them. They can make life horribly difficult.
Panic attacks are the typical response when confronted with, or even thinking about, the feared thing. Nausea, increase in heartbeat and wobbly legs are usual symptoms. Severe responses can lead to a feeling of choking or dying, chest pain and a terrifying out-of-body feeling. It is both frightening and highly stressful to the mind and body. Patterns of avoidance tend to be adopted where the sufferer will do anything to avoid an encounter that will trigger the reaction. Because most humans, to some extent or another, have at least one phobia, very severe ones are not always taken seriously.
George Washington had a fear of being buried alive, called Taphephobia. He demanded to be left out for two days prior to burial, such was the depth of his fear. Woody Allen has turned his many phobias, Panophobia; a fear of almost everything, into a hugely successful career, by satirising his anxieties. Not everyone has the genius to use this route. Hitchcock had Ovophobia, fear of eggs; Freud feared ferns and Napoleon Bonaparte was scared of cats. It is somewhat bizarre that the great military commander was the original scaredy-cat. Perhaps his ancestors can now shoulder that blame.
Treatment for phobias ranges from hypnotherapy to psychotherapy, with many trying to manage their fears on their own with self-help techniques. Cognitive behaviour therapy is said to be effective, as is desensitization, whereby the sufferer is gradually exposed to the thing that frightens them. People with life-long arachnophobia have been able to handle tarantulas after re-thinking their perceptions of them.
Katherina Hauner from Northwestern Medicine, showed spider-haters fMRI scans of their brains. These lit up in the amygdala, insula and cingulated cortex regions when they were confronted with a tarantula 10 feet away. These are all seats of the fear response. After three hours of explanation and information, refuting their beliefs – that the spiders were aggressive, and intent on harming them – participants could go up to, and eventually, touch and then hold the eight-legged arachnids. Immediately after this, the fMRI scans showed decreased fear. When re-tested six months later, the “cured” could still go up and touch the hairy spiders.
There is even an app now, to desensitize arachnophobes, which make up 6 percent of the population. Daily images are sent to their phones, acclimatizing them to the sight of the creatures. Once they get used to the augmented reality versions, they learn not to be so scared.
These findings do suggest that the phobias and fears that lurk in the mind can be mended, and that reframing negative thoughts is a big help. If indeed phobias have been wired into DNA and passed on from long-ago ancestors, it will be interesting to see if and how new treatments adapt. All people have a lot to thank their ancestors for. Nobody would be here without them. It could be they are also to blame for some of mankind’s more irrational inheritances.
By Kate Henderson