Fear is a learned social behavior that, at its most primal level, can arise in one of two ways. It can come about either through improper first exposure to an object, animal, or experience; or as a learned behavior from witnessing a fear response in another. These two categories of fear are conditioned; fear learning and observational fear learning. Both types of fear can be at play in developing a fear response such as cynophobia. Cynophobia is the irrational fear of dogs and it affects 1 in 20 people. It can be a debilitating fear preventing people from going places such as airports, parks, or anywhere they are likely to come across dogs. The irrational fear of dogs can disrupt a person’s life in unimaginable ways. In order to understand this fear we must look at both the brain and the stress hormone cortisol.
The amygdala is a structure within the brain responsible for emotions, although animals can have a varied level of response to stimuli. It is one of the oldest structures, evolutionary speaking, which means it remains relatively unchanged between species (1). Hyperactivity of the amygdala is present in people with PTSD, pregnant women who fear giving birth to a child with disabilities (2) and of course in people with phobias (3). All three of these examples show a heightened arousal to stimulus. A heightened reaction to stimulus is an individual trait. Some animals may exhibit an overreaction in the amygdala when exposed to an aversive stimulus. For example, a predator is naturally averse. Most animals will have an increase of activity in the amygdala when confronted with a predator. However, not every individual animal will have the same amount of increased activity, and in some it may be considered an overreaction of the amygdala.
The amount of fear exhibited is based on the individual. Part of this can be explained by the amount of maternal stress a child was exposed to in utero. During a stress or fear response, a major hormone released is cortisol. Higher reported fear in a mother during pregnancy significantly correlates with an increased fear response in an infant. This is measured by the amount of cortisol released when the child is subjected to a new experience after birth. These changes in the fear response are permanent for the extent of the child’s life because the threshold of tolerance for a fear response was set before the child was born due to the mother’s fear levels during pregnancy (2). This may contribute to irrational fears or phobias.
The most basic form of fear learning is conditioned fear. This means that a person learned to fear something because they had a direct negative experience. This type of fear was first studied by Pavlov who used animal models to create a fear response where there was previously none. He applied a benign stimulus, such as a sound, and then followed it up with a naturally averse stimulus such as a shock to the foot. Soon the animal exhibited fear upon hearing the sound (4).
What is more interesting is that a fear response can be created in an animal who is not experiencing a negative stimulus but only witnessing a fear response in another. This is observational fear and it is a powerful evolutionary tool when applied to the correct situations. For example when a group of mice witnessed another group who were exposed to pavlovian fear conditioning, the observational group also exhibited fear when presented with the sound that signaled an imminent negative stimulus (1). This is fear learning on a societal level and it allows for greater survivability of a species.
However, this beneficial evolutionary trait can easily be misdirected. “Children with sub-clinical animal phobias or extreme fears toward certain situations, such as darkness, often report having observed parents fearful in the same or similar situations” (1). This can result in the development of an irrational fear such as cynophobia. A child’s ability to respond appropriately to fear is vital for survival but when applied to the wrong stimulus can impair their ability to function in society. Cynophobia is the example used for this article, but is applicable to many different situations. Fear varies between people and across societies. It is dependent on a person’s individual biology, their personal experiences, and the experiences of those around them. No response is necessarily a wrong one but it is important to know what plays into learning what or what not to fear.
- Olsson A, Phelps EA. Social learning of fear. Nature Neuroscience. 2007;10(9):1095–102.
- Tollenaar MS, Beijers R, Jansen J, Riksen-Walraven JMA, Weerth CD. Maternal prenatal stress and cortisol reactivity to stressors in human infants. Stress. 2010;14(1):53–65.
- Larson CL, Schaefer HS, Siegle GJ, Jackson CA, Anderle MJ, Davidson RJ. Fear Is Fast in Phobic Individuals: Amygdala Activation in Response to Fear-Relevant Stimuli. Biological Psychiatry. 2006;60(4):410–7.
- LeDoux J. The Emotional Brain, Fear, and the Amygdala. Cellular and Molecular Neurology . 2003Oct;23(4).
This article first appeared in the April 2020 issue of Lifelines, the Life West student magazine.