INFANTS & THE SOUNDS OF ANCIENT DANGERS

There are many differences in animal species.  More advanced animals usually take longer to mature and exhibit less instinctual behaviors.  Humans are considered to have the least instinctual behaviors.  Many animal behaviors were thought to have been instinct, but were subsequently considered to be learned.  These instinctual and learned behaviors are sometimes difficult to distinguish between, so they can be collectively referred to as species specific behaviors.    

A new study investigated which human fears are instinctual and which ones are learned.  This study has concluded that babies have an ear for ancient dangers.

By the age of 9 months, infants pay special attention to various sounds that have signaled threats to children’s safety and survival since ancient times, claims psychologist Nicole Erlich of the University of Queensland, Australia. Those sounds include a snake hissing, adults’ angry voices, a crackling fire and thunder.  All of these sounds are possible indicators of a nearby, but unseen danger.

Noises denoting modern dangers, as well as pleasant sounds, failed to attract the same response from the 9 month old infants, Erlich and her colleagues report Aug. 27 in Developmental Science.

The scientists propose that people can learn to fear just about anything, but tens of thousands of years of human evolution have primed infants’ brains to home in on longstanding perils.  “There is something special about evolutionarily threatening sounds that infants respond to,” Erlich says.

In the study, 61 male and female infants sitting in highchairs near a parent briefly heard through speakers a series of ancient danger sounds, modern danger sounds and pleasant sounds.  Modern danger sounds included glass breaking and a siren wailing. Pleasant sounds included classical music and a baby laughing.

In response to ancient danger sounds, infants experienced a higher increase in heart rate, more eye blinks and increased turning toward the speakers or parent.  All of those indicate that they were afraid.   

Previous studies found that infants first recognize adults’ expressions of fear between 5 and 7 months of age.  Learning what to fear begins around that time and proceeds more easily and quickly for ancient threats.

If these ancient fears are instinctual and hard wired into our DNA, the next question would be, how did they get there to begin with?  Darwin’s theory of natural selection would say that humans that were naturally more fearful of these ancient threats, had an increased probability of survival and that fear was passed down from generation to generation.

For More Information:

http://articles.timesofindia.indiatimes.com/2013-09-11/science/41969476_1_sounds-infants-babies