The Placebo of Astrology: Horoscope Rx Edition

Leanna M.W. Lui, HBSc


August 09, 2021

Have you checked your horoscope for today?

I’ve always thought horoscopes were entertaining. They are like Kinder Surprise candy treats waiting to be opened at the beginning of the day. At the same time, they also provide an oddly comforting feeling, especially when I’m having an odd day. Just having a generic explanation to justify my low mood or lack of productivity was enough to give me a chuckle. However, all in all, I’ve never been a big supporter of horoscopes simply due to their lack of scientific basis. 

Have you ever read a horoscope and thought that it's pretty accurate? Or that could be accurate? Or that’s within the realm of possibility? If you said yes to any of the above, then the horoscope is doing its job. Horoscopes provide generic forecasts of the future based on the individuals’ date of birth, and the aligning stars and planets. They typically provide “insight” into careers, relationships, and general personal development. 

Horoscopes are designed to induce the Barnum Effect. The Barnum Effect, also known as the fallacy of personal validation, is the psychological effect of believing generic information is specific to one’s personal situation. In other words, it refers to the tendency to believe generic information refers to one’s unique personality.

If you’ve ever read a horoscope and thought that it resembles or appeals specifically to your situation, then you’re under the spell of the Barnum Effect. This cognitive bias known more specifically as subjective validation occurs when individuals take a general statement and attach personal significance (i.e., relating two unconnected events and attaching a personal relationship).

As an example, the horoscope posted by the National Post for Scorpios on the day I wrote this reads:

“Starting today, everything to do with home and your relations with family members will improve for the rest of year. Yay! Family members will be more generous to each other. Likewise, you will renovate, redecorate or relocate to improve your digs.”

To some degree, this is accurate. I’ve been spending a lot more time with my family. We’ve been able to cook for one another, have movie nights and we’ve been calling our relatives overseas more. Additionally, I’ve been doing some home and computer organization, and general “summer” cleaning. All in all, this seems accurate and personal to some degree, but again, it’s quite generic. There hasn’t been a time where I wasn’t catching up with family or maintaining my home and work life. 

The Barnum Effect can be incredibly powerful especially when the remarks are on a positive note. Most people enjoy receiving compliments and reading positive outlooks about themselves; they are likely to be much more receptive and accepting of positive statements. On this train of thought, most are less willing to accept negative or critical remarks. The Pollyanna principle, which refers to positivity bias, refers to the increased likelihood of assuming greater accuracy of positive statements ꟷ consequently, individuals are more likely to reject criticism. 

It’s incredible how widespread the following of horoscopes is and how many people are convinced of their “predictive abilities.” However, when we boil down the “science” of horoscopes, all we are left with are psychological phenomena.

Next time you read a horoscope, will you take it to be a sign of the future or some light and entertaining reading as you get ready for Monday morning?

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About Leanna Lui
Leanna M.W. Lui, HBSc, completed an HBSc global health specialist degree at the University of Toronto, where she is now an MSc candidate. Her interests include mood disorders, health economics, public health, and applications of artificial intelligence. In her spare time, she is a fencer with the University of Toronto Varsity Fencing team and the Canadian Fencing Federation.


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