The sight of blood and gore can provoke a vastly different response from person to person – while some can binge-watch splatter films with glee, some people can’t bear the thought of the crimson life juice without fainting. Why, if we all (hopefully) have blood coursing through our bodies as we speak, is it such a polarizing substance?
Why am I squeamish around blood?
Negative feelings upon seeing blood make sense when it comes to taking care of yourself and others, as your blood should generally be on your inside rather than your outside – “Seeing blood obviously reflects something bad happening around you,” Dr Joseph LeDoux, professor of neuroscience at New York University, told the Association of American Medical Colleges (AAMC).
The term “squeamish” is associated with feelings of disgust and nausea. This also makes sense from a health perspective – exposure to blood can potentially expose you to blood-borne pathogens such as hepatitis and HIV.
“According to pathogen-avoidance perspectives on disgust, injuries, gore, mutilation, or body-envelope violations [e.g. stabbing] elicit disgust because they have infectious potential,” one 2018 paper reads. However, the author suggests an alternative reason: “People empathically simulate an observed injury, leading to unpleasant vicarious feelings.”
However, why do some people faint around blood when it can be a sign of imminent danger? Blame blood pressure. Called vasovagal syncope, stimuli such as the sight of blood can cause overactivation of the vagus nerve, thus a sudden drop in blood pressure and heart rate. This restricts blood flow to the brain, making you faint.
A phobia of blood
Sometimes, someone’s fear of blood can get so intense that it interferes with their life. This can reach the point of becoming a specific phobia, sometimes referred to as hemophobia – or officially, in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), blood-injection-injury (BII) phobia.
This phobia is estimated to affect 3 to 4 percent of the general population. A survey conducted in the Aligarh region of Utter Pradesh, India, indicated an average age of onset of 9.3 years for males and 7.5 for females, in line with the DSM-5’s estimate for the median age of onset for specific phobias in general, which is between 7 and 11 years old.
A fear of blood can be caused by traumatic events: “This might have been a visit to a doctor or an accident, and, as a child, the person experienced intense fear. At that time, blood became associated with danger, and this association has persisted,” Dr Eric Bui, acting director of the Center for Anxiety and Traumatic Stress Disorders at Massachusetts General Hospital, told AAMC. However, some people with phobias can’t think of a specific reason for them developing.
BII phobia can lead to people avoiding medical care due to fear and anxiety, which can be immediately dangerous as well as detrimental to their health in the long run. The DSM-5 also notes: “Individuals with blood-injection-injury phobia show a unique propensity to vasovagal syncope (fainting) in the presence of the phobic stimulus.”
Why do we like blood in movies?
On the other hand, if so many people find the sight of blood disgusting or frightening, why are many beloved pieces of media absolute bloodbaths (sometimes literally)?
It has been suggested that people partial to a bit of blood and guts are more “sensation-seeking”. Also, as psychologist Dr Lee Chambers told Salon: "We get to consume something we see little of in real life, in a controlled and safe environment, where we can test the limits of our emotive response in comfort."
A 2014 study titled Captivated and Grossed Out: An Examination of Processing Core and Sociomoral Disgusts in Entertainment Media explored why we find icky stuff so compelling. The study explored different types of disgust: sociomoral disgust, and “core” disgusts toward body envelope violation, and body products like feces.
“Disgust, it is argued here, makes us feel bad – but it has functionally evolved over time to compel our attention, thus making it a quality of entertainment messages that may keep audiences engrossed and engaged,” the study authors write. “This study suggests that the blood and gore associated with body envelope disgusts elicits a negative – but not defensive response – which is ideal for recognition memory.”
Researchers recruited 120 college students, asking them to indicate emotional responses to TV and film clips and complete a recognition memory task, where they had to determine whether a screenshot had appeared in the clip they were shown.
“All types of disgust in this study elicited heart rate deceleration and strong attentional responses and improved memory for the disgusting content and for information that followed its onset. Core disgusts had extremely poor memory (near chance) for information that preceded the onset of disgust. This may mean that responses to core disgusts act as a cognitive interrupt, immediately focusing the cognitive and motivational system on this important survival related stimulus and resulting in retroactive inhibition of memory,” the paper reads.
“From an evolutionary perspective, an attentional bias toward disgust – no matter how aversive – would better equip humans to avoid harmful substances. Disgust-related contaminants are often tied to survival opportunities like food and sex, providing even more motivation for one to correctly identify potential threats.”
So, it seems that feelings around blood tend to center around survival – whether your instinct is to pay close attention or run far away.