The Science of… Halloween: #2 Creepy Curses
- Lit Lab
- Oct 12
- 3 min read
Welcome to our Halloween-themed science blog!
It’s Halloween season, so throughout October we’re untangling science from superstition each week with a blog exploring everything from potent potions to creepy creatures - and even eerie experiments you can try at home.
Check back each week during October to see what science is brewing behind the magic!
#2 Creepy Curses
Science shows that belief itself can shape your physical health. You’ve probably heard of the placebo effect — when people feel better after taking a sugar pill simply because they believe it will help. But its darker twin, the nocebo effect, does the opposite, where belief in harm creates harm.
In experiments where people were told a harmless cream would cause pain, their brains reacted exactly as if they’d been injured. Fear and expectation alone switched on pain-processing circuits, showing that belief can make the body respond as though a ‘curse’ were real.
Science describes multiple pathways for how this happens, where expectation, conditioning (learning), and contextual cues (words, tone, ritual) all intertwine.
Brain imaging studies show that the expectation of harm activates the anterior cingulate cortex and insula — the same regions linked to modulating pain perception signals and emotion regulation. So if someone truly believes harm is coming, the body can create it chemically.
Nocebo responses can also be learned. If you’ve ever felt pain after hearing a warning or watching someone else flinch, your body may start to associate those cues with harm. Your brain may flag these as “danger signals”, activating stress systems, amplifying pain pathways and releasing neurotransmitters that worsen your perception of the event or ‘symptom’ and priming your body for a reaction before anything physical even happens. Over time, that stress chemistry can cause headaches, fatigue, nausea, even changes in heart rate or immune response.
Scientists who have studied this warn that “curses” have a parallel in modern medicine: overdiagnosis. When someone is warned too strongly about possible side effects or told they’re “at risk,” those expectations can sometimes make them feel worse or even develop symptoms they might not have had otherwise.
This is can be dangerous as false diagnoses, negative prognoses, or even routine warnings about common symptoms can trigger real harm via the nocebo pathway. It’s the same mind-body loop at play: the more we believe in harm, the more the body cooperates.
Psychologists exploring illusion and suggestion have found that simple tricks can make people feel as though their thoughts or actions aren’t their own — as if controlled by some unseen force.
Some psychological/neuroscience studies have intentionally used deception (or magic tricks) to interfere with a person’s sense of agency — making them feel as though their thoughts or actions are controlled by aliens or external forces. (Look up e.g. “Simulated thought insertion … magic deception” studies.) These manipulations can shift the bodily response, showing how suggestion and expectation can “hijack” our experience. Add fear, ritual, and belief, and you have the perfect recipe for a so-called curse.
So, are curses real? Not in the supernatural sense, but their effects can be real. Fear, expectation, negative framing, and ritual can shape our physiology in powerful ways. Understanding the nocebo helps us see curses as metaphorical warnings, telling us to treat beliefs carefully.
This Halloween, remember: your brain is the most potent spellbook you own. Guard your thoughts — and your words — wisely.
Would you have imagined that curses can have real effects on people?
Tell us your thoughts in the comments or tag us on socials @LitLabLondon
Looking for more spooky science fun?
Join us this Halloween and enjoy enough shots to wake the dead at the Lit Lab: Halloween Special on Sun, 26 Oct at Aquum, Clapham
Sources:
Andrea, Danielle and Antoinette (2014). Placebo and Nocebo Effects in Itch and Pain. Handbook of experimental pharmacology, pp.205–214. doi:https://doi.org/10.1007/978-3-662-44519-8_12.
BPS. (n.d.). The placebo effect, digested. [online] Available at: https://www.bps.org.uk/research-digest/placebo-effect-digested [Accessed 10 October 2025].
Colloca, L. (2017). Nocebo effects can make you feel pain. Science, 358(6359), pp.44–44. doi:https://doi.org/10.1126/science.aap8488.
Frisaldi, E., Shaibani, A. and Benedetti, F. (2020). Understanding the mechanisms of placebo and nocebo effects. Swiss Medical Weekly, 150(3536). doi:https://doi.org/10.4414/smw.2020.20340.
Justman, S. (2015). The Nocebo Effect. Palgrave Macmillan.
Olson, J.A., Landry, M., Appourchaux, K. and Raz, A. (2016). Simulated thought insertion: Influencing the sense of agency using deception and magic. Consciousness and Cognition, 43, pp.11–26. doi:https://doi.org/10.1016/j.concog.2016.04.010.
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