JUN 24, 2019 8:15 PM PDT

Are Our Instincts Really Genetic?

WRITTEN BY: Annie Lennon

Genetic explanations for our instincts are incomplete. Although they explain to some degree how we learn and suggest how these learnings are passed on, their exact mechanisms are still unknown. This in mind, is it possible that our genetics are not fully responsible for our instincts? Is it possible that there is a limit to how much our genetics can explain our behaviors?

Research has shown that genetics may not be able to completely predict our instincts. Instead, it may be that behaviors rely much more on context- from our environment to how our bodies are able to function, and that this may happen in both striking and subtle ways. In this way of thinking, our instincts are not preprogammed nor hardwired. They instead emerge each generation through a complex interplay of physical and biological factors (Blumberg: 2016).

Several studies and examples have demonstrated this theory. One such study did this by assessing the vestibular system in rat pups. Similarly to cats, newly born rat pups are known to have a ‘righting response’. When they fall from a height, their vestibular system detects changes in their acceleration and activates certain muscles throughout their body to flip them onto their feet before hitting the ground.

In an experiment to determine whether this trait is instinctual, researchers flew pregnant rats on the NASA Space Shuttle during the period of gestation when the vestibular system develops. They were then returned to earth two days before giving birth. Soon after birth, the vestibular systems of their intergalactically-gestated offspring were tested.

Rather than being dropped from a height however, they were gently dropped upside down into a warm tank of water. Normally when faced with this circumstance, rat pups automatically flip onto their feet, clearly demonstrating a functional vestibular system. These pups however sunk to the bottom of the tank on their backs- their time in space had seemingly affected their vestibular system from developing. Yet, after just a week, they were able flipping onto their feet, just as rat pups who were fully gestated on Earth (AE: 2008).

For researchers, this demonstrated that the vestibular response was not necessarily solely developed during gestation, and that its functionality was perhaps a response to gravity as opposed to something innate. Although it became an instinct under certain circumstances, in their absence, it was not necessary to develop, and so didn’t. These findings of course highlight the importance of the interplay between one’s environment to enable certain genetic factors. Rather than rely on genetics to categorically explain instincts, the context in which they come about is also important to bear in mind.

This thought process is especially relevant when considering other examples of life born in unusual circumstances. For example, Johnny Eck was a performer born with a condition known as ‘amelia’ in which both of his legs were short and functionless. Similarly to other individuals with the same condition, he learned to walk fluidly and gracefully on his hands. He was even able to walk down steps and climb ladders (Blumberg: 2016).

Similarly, people who are born blind at birth typically develop echolocation- the ability to detect objects and their proximity by deciphering reflective audio cues, without deliberate learning (Brogaard: 2015). Although these traits may not be present in most of the population, the potential for their development may be more influenced by how our bodies must react to our environments to best live, as opposed to being genetically inevitable.

Thus, perhaps in looking solely out genetic inputs and outputs for tangible behaviors, we are missing the point of genetic inheritance. Rather than strictly governing our behavioral and motor outputs, our genes may be more reactive to the environment to innately promote behaviors and traits that give us the best chance of survival. Thus, rather than considering them as precise building blocks in regards to our behavior and motor functionality, they may more so provide a drive to fulfil certain needs in a way that makes the most of available resources.


Sources

 

Blumberg, Mark S: PMC 

AE, Ronca: Pub Med 

Brogaard, Berit, Discover Magazine

 

About the Author
  • Science writer with keen interests in technology and behavioral biology. Her current focus is on the interplay between these fields to create meaningful interactions, applications and environments.
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