The horoscope and astrology are very commonly used to predict the future . Many newspapers and websites get a significant number of readers because they include daily predictions based on the zodiac sign, not always following the “official” mathematical and astrological methods.

However, not only are the interpretations in newspapers and on websites highly likely to be false, but the horoscope itself is a scam; we explain why by using very basic psychological concepts.

What is the horoscope?

“Horoscope” is a term of Greek origin; “horoskopos” comes from the words “hõra” (which is translated as “time”) and “skopeo” (“to examine”, “to observe”).

The word refers to the pseudoscientific system used to predict a person’s future based on the positions of the stars at birth or at some other special time. Those who interpret these signs are called astrologers.

In Western astrology, predictions are based on the position of the sun, while the Chinese horoscope also takes into account the position of the moon, since it is based on a lunar calendar and not a solar one.

What are the signs of the zodiac?

The birth chart is divided into 12 sectors that represent different positions of the Ecliptic , that is, the apparent path that the sun makes around the earth when it is observed from it. Each of these segments is identified with a zodiacal sign.

The signs of the zodiac represent the 12 constellations of the Ecliptic. To each of them are attributed different characteristics that are supposed to influence the psychology of people born at the moment the Sun crossed a certain sector of the Ecliptic.

Each sign is attributed a “positive” or “negative” pole (extroverted and active versus introverted and passive) and an element (water, air, earth or fire).Other important elements besides the zodiacal signs are the planets, which are also said to influence the personality, and the so-called “houses”, which determine the relative influence of each planet on the person’s psychology .

How do you interpret it?

The birth chart is calculated using the exact date of the person’s birth, including time and minutes, and the latitude and longitude of the place where it occurred.

The calculations in the birth chart are aimed at locating the “Right Ascension of the Midheaven”, which supposedly determines which planets influenced our personality at the time we were born.

Within astrology, interpretations made using only the position of the planets are considered invalid: according to horoscope experts, it is necessary to make a series of mathematical calculations in a certain order. However or most of the time these prescriptions are ignored, especially in newspapers and websites .

Scientific basis

Numerous studies have been carried out using scientific methodology to study the hypotheses proposed by astrology and the horoscope, including longitudinal studies with reliable control techniques.

None of these studies have found that the probability of stars influencing our psychology is higher than having a personality trait determined by chance. Therefore, we can say that the scientific basis of the horoscope is null and void, since there is sufficient evidence to state that the position of the stars at the time of birth does not influence personality.

Astrology has proposed various mechanisms by which stars could influence our behaviour, such as electromagnetism and gravity, but these are hardly plausible from a physical point of view.

Because of these reasons, horoscopy and astrology are classified within the term “Esotericism”, referring to practices not based on science but on apparently arbitrary methods whose learning requires training by supposed experts.

Psychological explanations

Although science in general shows that the horoscope is a fraud or at least that its predictions are not based on reality, contributions from psychology are needed to explain why so many people believe that it works .

The Forer effect

Scientific studies have shown that people tend to identify with very vague personality descriptions if they are told that they describe us specifically. This is known as the “Forer effect” or “Barnum effect”.

Bertram R. Forer was a psychologist who had his students fill out a personality test . Later he gave them a supposed description of the personality of each one, asking them to evaluate from 0 to 5 the extent to which they felt identified with him; the average result was 4.2.

Actually, Forer had given everyone the same description based on horoscopes. The text included extremely vague statements such as “Although you have defects you are usually able to compensate for them” or “Sometimes you are outgoing, affable and sociable but other times you are introverted, cautious and reserved”.

Interestingly , other similar studies have shown that people tend to identify more with descriptions of this type , including those of some personality tests, than with the results of psychological tests supported by science.

This is because we more easily believe what people we consider experts say and because ambiguous phrases allow us to interpret descriptions in a subjective way, projecting a personal meaning to their statements. It is probably also influenced by the fact that in general horoscopes tell us positive things, while this is not always the case with serious personality tests.

The confirmation bias

We call “confirmation bias” or “confirmatory bias” the tendency for people to prefer information that confirms our beliefs over information that supports alternative hypotheses, which we are much more likely to ignore.

In the horoscope and other aspects of esotericism, the confirmation bias is very frequent . Normally when we read a horoscope or a “professional” reads the Tarot cards, a large number of statements come to us, among which we will pay more attention to those which seem to fit our self-image. We will also remember more the phrases which “hit” when describing ourselves.

Confirmation bias is constantly present in our lives. Whenever we seek, receive, remember or interpret information we are unwittingly favoring the views we already have. The only way to avoid this reasoning error to some degree is to be actively aware of when we are making it.

If you believe in the horoscope, when you read this you will probably prefer to think that it is the scientists who have studied the hypotheses of astrology systematically and not you who are wrong; this is a good example of confirmation bias.

The horoscope is just another scam

There are many pseudosciences, i.e. disciplines that present themselves as scientifically plausible but do not actually follow the scientific method or have any claim to do so. In general these esoteric practices are based on false premises and/or use arbitrary methods.

It is important to make it clear that, while the sciences are considered as such because their perspectives are derived from previous scientific knowledge, pseudosciences make similar claims but do not have a solid body of research to back them up, so that on many occasions they try to take advantage of the status conferred by the adjective “scientific” without having been able to prove their hypotheses.

The confirmation bias and the Forer effect, which have been widely demonstrated by science, may be sufficient to state that the horoscope is a fraud , if we add them to the studies which have refuted the hypothesis that the position of the stars at the time of birth influences personality.