By Lucy Lewis
Halloween is the time for all things scary, and the best thing for scaring people is to put on a good horror movie, preferably something with creepy dark figures appearing suddenly after a long, tense build up. But what is it about these films that gets us so freaked out?
Fear is an integral part of our survival mechanisms, it is a part of the ‘fight or flight’ response to prepare us for combating or escaping from a potential threat. Deep down, you know the demons from Insidious aren’t real, and the clown from It isn’t going to appear behind the sofa, and yet we jump at their appearance on screen, hide behind pillows when the music goes tense and even continue thinking about them once the film is finished.
Scene from ‘A Nightmare on Elm Street’ (1984).
This is because horror movies tap in to this innate survival mechanism by presenting us with a situation/character that looks like a threat. When we see something potentially threatening, this activates a structure in the brain known as the amygdala, which associates this threat with something to be fearful of (Adolphs 2013). The amygdala acts as a messenger to inform several other areas of the brain that there is a threat present, thus resulting in multiple physiological changes, including the release of adrenaline (Steimer, 2002) which causes the typical bodily functions we experience during fear, e.g. increased heart rate.
Even though we know the movie isn’t real, the amygdala takes over our logical reasoning to produce these responses, a phenomenon known as the “amygdala hijack” (Goleman, 1995). This is when the amygdala stimulates these physiological changes to prepare us against this fearful threat before the prefrontal cortex of the brain, responsible for executive functions, can assess the situation and regulate our reactions accordingly (Steimer, 2002).
In fact, studies looking into fear conditioning, which is when associations are made between a neutral stimulus like a clicking sound and an aversive stimulus like an electric shock (Gilmartin et al 2015), have shown that inactivation of the medial prefrontal cortex results in a deficit in the ability to disconnect this association, suggesting that the prefrontal cortex is necessary for the extinction of a fear memory (Marek et al, 2013).
A schematic diagram of the fear pathway, adapted from a VideoBlocks image.
You’ve probably noticed that you can also remember something that scared you so much better than even remembering what you had for breakfast. Forming memories of the events that cause us to feel fear is important for our survival mechanisms, because it helps us to avoid threats in the future. Evidence suggests that the stress hormones that are released following exposure to fearful events contribute to the consolidation of memories, for example Okuda et al (2004) gave rats an injection of corticosterone (the major stress hormone for rodents) immediately following one training session of a task requiring the animals to remember objects presented to them in an arena. They showed that, 24 hours later, the animals that received this injection showed significantly greater recognition of these objects than controls, suggesting that this stress hormone increased their ability to remember the objects around them. Therefore, the scarier the film, the more we remember it.
So, don’t worry if you are a big scaredy-cat when it comes to horror films, it’s actually natural! It’s just your brains response to a threatening situation, and you can’t control it no matter how hard you try. But if you are planning a film night full of ghosts and ghouls this Halloween, go and get yourself a big pillow to hide behind and prepare for that good old amygdala to get into action!
Adolphs, R. 2013. The Biology of Fear. Current Biology, 23:R79-R93.
Gilmartin, M. R., Balderston, N. L., Helmstetter, F. J. 2015. Prefrontal cortical regulation of fear learning. Trends in Neuroscience, 37:455-464.
Goleman, D. 1995. Emotional Intelligence: Why It Can Matter More Than IQ. New York: Bantam Books.
Marek, R., Strobel, C., Bredy, T. W., Sah, P. 2013. The amygdala and medial prefrontal cortex: partners in the fear circuit. Journal of Physiology, 591: 2381-2391.
McIntyre, C. K. and Roozendaal, B. 2007. Adrenal Stress Hormones and Enhanced Memory for Emotionally Arousing Experiences. In: Bermudez-Rattoni, F. Neural Plasticity and Memory: From Genes to Brain Imaging. Boca Raton (FL):CRC Press/Taylor & Francis, Chapter 13.
Okuda, S., Roozendaal, B., McGaugh, J. L. 2004. Glucocorticoid effects on object recognition memory require training-associated emotional arousal. Proceedings of the National Academy of Science, USA, 101:853-858.
Steimer, T. 2002. The biology of fear- and anxiety-related behaviors. Dialogues in Clinical Neuroscience, 4:231-249.
VideoBlocks, AeMaster still photo from: 3D Brain Rotation with alpha. https://www.videoblocks.com/video/3d-brain-rotation-with-alpha-4u23dfufgik3slexf