- Fear and disgust for snakes and
spiders are evolutionary and innate in humans.
- Babies as young as six months old
feel stressed when they see these creatures
- The fear may be associated with
the co-existence of human ancestors and these
groups of animals which could be potentially dangerous.
For a long time,
research has been trying to identify if the instinctive fear humans have for
spiders and snakes is innate or learnt through life. A new study by Max Planck Institute for Human Cognitive and Brain
Sciences (MPI CBS) in Leipzig and the Uppsala University has discovered that it
is innate and hereditary.
developed countries, where humans do not come in contact with spiders or snakes, are frightened by
these creatures that they have hardly seen. While the debate has continued over
the years to determine if this fear is acquired or is it in-born. A new study
by research teams at the Max Planck Institute for Human Cognitive and Brain
Sciences (MPI CBS) in Leipzig and the Uppsala University have shown that the response of fear and aversion is in-born and hereditary.
In some people, the fear is so profound that they develop into anxiety
and phobias. Such people find it difficult enter a room with
a spider and cannot go out into the wild due to the fear that they may
encounter a snake.
Overview of the Study
studies on this topic were conducted with adults or older children, which made it hard to distinguish between learnt and in-born fear. Also, these studies only tested
whether children were able to spot spiders and snakes faster compared to other
harmless animals. The studies did not necessarily focus on establishing a
direct physiological fear
‘The reaction of fear and aversion that we exhibit towards spiders and snakes could be of evolutionary origin and not acquired through exposure to these groups of animals.’
The new study
has adopted a research design that overcomes the limitations of previous
studies by testing the fear response in children as young as six months. The findings of the study are crucial in understanding the
origin of this fear. Even in infants a stress reaction was evoked when they saw
a spider or a snake. Moreover, this was at the age of six months, where they
are still very immobile and have had little or no opportunity to learn that
these animals can be dangerous.
When the babies
saw a snake or a spider, instead of a flower or a fish
of the same size and color, their pupils enlarged significantly. This change in
the size of the pupils is an indication that the noradrenergic system in the
brain is activated, a region responsible for stress
reactions. This indicates that the babies felt
stressed looking at these animals.
other studies have shown that babies do not associate pictures of rhinos, bears
or other theoretically dangerous animals with fear.
The Evolutionary Link
While the study
has proved that the fear of spiders and snakes is hereditary and something that
humans are born with, even before the exposure to such
creatures, the reason for this is unclear.
suggests that this may in fact be a protective evolutionary measure embedded
into our genes due to the co-existence of these potentially
dangerous animals with humans and their ancestors for more than 40 to 60
This may the
reason why pictures of animals we consider dangerous today, like a lion or a rhino do not invoke a fear response in babies.
These animals haven't been in co-existence with human
ancestors and are relatively new in terms of evolutionary distance compared to
snakes and spiders.