Horoscopes and personality tests such as Myers-Briggs are believed by people of all types of backgrounds despite the fact that research has proven them to be easily falsified. Why?
Well, the main reason for their popularity is because they are vague, positive generalisations that almost can’t help but be true for most people.
Psychologists call this the Barnum effect, whereby people will accept feedback about their personality, no matter how trivial or general, because they believe it is based on personality assessment procedures.
The effect is named after P.T. Barnum, the famed American showman and circus owner who claimed 'There's a sucker born every minute' and whose formula for success was 'A little something for everybody'.
According to research on the Barnum effect, people believe in astrology because they fall victim to the fallacy of personal validation.
In other words they take the generalised, trite, bogus descriptions, which are true of nearly everybody, to be specifically true of themselves.
One of the most famous (and embarrassing) examples of this phenomenon took place in the late 1950s when Ross Stagner, an American psychologist, gave 68 personnel managers a well-established personality test.
But instead of scoring it and giving them the results, he handed each person a bogus feedback in the form of 13 statements derived from horoscopes, graphological analyses and so on.
He then asked each manager to read the feedback (supposedly derived for him/herself from the 'scientific' test) and decide how accurate the assessment was by marking whether each sentence was: amazingly accurate, rather good, about half and half, more wrong than right or almost entirely wrong.
More than a third felt their profile was an amazingly accurate description, while 40 per cent thought it was rather good. Almost none believed it to be very wrong.
A crucial component of the Barnum effect is that people tend to be hungry for compliments but sceptical of criticism.
Feedback must be favourable. It need not be entirely positive, but if it is by and large favourable with the occasional mildly negative comment (that itself may be seen as a compliment) people will believe it.
Hence the flourishing popularity of horoscopes and the natural heirs to the throne, personality tests – they cleverly disguise how wrong they are for you by being right for everyone.