Why Your Horoscope Always Feels Right

Why do we feel that horoscope readings or fortune-telling are so accurate? Why does public debate over social policy tend to harden into two opposing camps? Why are prejudice and discrimination so common? All of these are tied to one human behavioural tendency — a tendency psychologists call confirmation bias.

So what is confirmation bias? Put simply, it is the human tendency to accept information that confirms or reinforces what we already believe, while resisting information that contradicts our existing ideas and beliefs. It shows that, much of the time, the human brain processes information in ways that are irrational.

Here are a few everyday examples to illustrate the idea. Whenever people read descriptions on an astrology website or Facebook page (for instance, that Taureans love money and are stubborn, that Aries are passionate, and so on), the brain of a Taurus or an Aries immediately starts hunting for personal examples that fit those descriptions. A Taurus, for example, will instantly recall plenty of times they were stubborn, and then cry out, "Wow, this is so accurate! I am a textbook Taurus through and through!" At that moment, the Taurus's brain is not inclined to recall the times they were not stubborn or did not care about money — it simply ignores any information that runs counter to the horoscope's description.

Take another example: when people discuss social and political events, opinions easily polarise into two extremes (such as the standoff between the yellow and blue camps in Hong Kong in recent years). Why does this happen? This too is the effect of confirmation bias. Just look at your own Facebook feed. If you are in the blue camp, would you tend to follow the pages of yellow-camp news commentators? No. If you are in the yellow camp, would you enjoy listening to blue-camp talking points? No. Because we selectively take in information that aligns with what we want to hear, the messages we receive grow more and more one-sided — and that one-sided diet only reinforces what we already believe, gradually nudging society as a whole towards two extremes.

Prejudice and discrimination (more on this later) are also linked to confirmation bias. Black people, for instance, are often discriminated against; in the eyes of some white people, there is a whole set of "facts" about Black people that they believe to be true — for example, that Black people are violent. So these white people selectively take in media reports about Black violence, which further strengthens their prejudice, while overlooking the many stories of Black people doing good. In this situation the media play an undeniable part: they latch onto this human behavioural tendency and focus heavily on reporting violent cases involving Black people (because that is what everyone wants to watch), indirectly becoming one of the forces that reinforce people's tendency to hold prejudice and discrimination against Black people.

If this kind of behavioural tendency is so irrational and inaccurate (along with many, many other behavioural biases), then why does it still appear in the human mind? Bear in mind that humans are just one kind of animal, and any trait or behavioural tendency that remains in our species must have its own adaptive significance — in other words, these behaviours matter for the survival of the species. So why is confirmation bias important for our survival? One reason is that it saves energy quickly: by taking in only information consistent with what we already believe, our brain does not have to spend energy thinking things through (conserving energy is a hugely important factor for the survival of a species).

As you slowly learn more psychology, you will discover just how irrational humans can be. The greatest gain from studying psychology is that we come to understand how many behavioural biases humans have — for example, how confirmation bias can deepen discrimination. When we see this behavioural tendency in others, we do not blame them for it, because we know it is the natural behaviour of this animal we call human. But once we have learned psychology, we ourselves should no longer be swayed by these behavioural tendencies, because we have grasped this knowledge. To learn is to progress — to make ourselves a little better each day, and to grow ever wiser. Be strict with yourself, and generous with others.

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Author – Lo’s Psychology Reproduced under special authorisation. Content may have been lightly edited.

Ph.D in Psychology, The University of Hong Kong
Ph.D in Psychology, HKU