He placed a succession of hungry pigeons inside a cage

where an automated machine delivered food to them at certain intervals

and observed that the birds started repeating actions

that had coincided with the delivery of the food.

They behaved as if their actions were influencing the food to appear

as if there was some causal connection, when in fact there was none:

the food would have appeared at the same intervals, whatever the birds did.

At about the same time Skinner published his paper, "Superstition in the pigeon"

psychologist Bertram Forer was conducting a study

relating to a human superstition, astrology.

He gave each of his subjects a test

followed by a confidential personality analysis

which he told them was based on their test results.

When they were asked to rate their analysis for accuracy

on a scale of nought to five, five being the most accurate

the average rating came out as 4.26.

Forer later revealed that all subjects had received exactly the same analysis

taken from horoscopes in an astrology book.

The Forer Effect, named after him

refers to people's tendency to be impressed by personality readings

given by astrologers and other pseudo-scientists

which they're led to believe are tailored to them individually

but are actually general enough to apply to most people.

Forer's experiment, which has been replicated many times

with the same basic results, is an important demonstration

that the seemingly impressive accuracy of horoscopes

can easily be reproduced without birthdays

or planetary positions playing any role.

According to superstition

a wedding ring dangled over the belly of a pregnant woman

can predict the baby's gender.

A circular motion predicts a girl.

A straight pendulum swing predicts a boy.

This involves the same mechanism found in dowsing

the superstitious belief that one can detect underground water

or other hidden substances with dowsing rods.

It actually works by amplifying small, almost imperceptible movements of the hand.

This hand movement is often an unconscious 'ideomotor effect'

whereby one's expectations lead one to make involuntary movements

in line with those expectations.

Sometimes, dowsing rods are even used on maps

which are declared somehow to have the same detectable 'energies'

as the terrain they depict.

Wedding ring predictions, dowsing

automatic writing and ouija board activity

have all been attributed to the ideomotor effect

though the person making the involuntary action might be convinced

the movement is coming from elsewhere.

Of course, often, there is a deliberate attempt to deceive others.

The belief that we can contact spirits with ouija boards

is one of countless superstitions surrounding death

and countless television shows seek to give evidence

of ghosts and spirit-channeling.

Viewers send in footage in which spots of light are leapt on

as so-called ghostly 'anomalies'

and self-proclaimed mediums declare they can channel spirits

in shows that disclaimers admit are 'for entertainment purposes only'.

Interestingly, when magicians give their audiences

apparently uncannily accurate details about their lives and relationships

our typical response is "What's their trick?"

But when others do the same, posing as psychic mediums

the response is often, "They must have supernatural powers".

All that differs between the self-proclaimed medium and self-confessed showman

is presentation style.

If the showman doesn't need supernatural powers, nor does the medium.

In the fifth season of the so-called ghost-hunting show Most Haunted

its resident medium, Derek Acorah, behaved as if possessed

by the spirit of 'Kreed Kafer'.

But it was later reported that this name had been invented

and misinformation about the fictitious person had been fed to Derek

prior to filming, to test his integrity.

As filming began and Derek became swept up in the persona

of the non-existent spirit, he didn't realise that 'Kreed Kafer'

was an anagram of 'Derek Faker'.

He went on to channel a similarly fictitious highwayman

whose name was an anagram of 'Derek Lies'.

Many superstitions revolve around the treatment of illness.

And many want their superstition to be regarded as authentic medicine.

Homoeopathy involves preparations that have been repeatedly and extremely diluted

until it's statistically uncertain that there's even one molecule

of active ingredient present.

How do homoeopaths justify selling water as medicine?

They claim water has a memory of the substances with which it's had contact.

A major problem with this claim, even if there were valid evidence to support it

is that the water the homoeopath sells you may have had contact

not only with the substance claimed to treat your health

but with countless other substances during its natural existence.

The '10:23' campaign has staged mass overdoses

of homoeopathic products around the world

to protest against their sale

and raise awareness of the problems with homoeopathic claims.

Homoeopathy hasn't been shown to have any effect beyond placebo:

when receiving and having confidence in a dummy treatment

can itself lead to an improvement in health.

Some feel that if placebos sometimes show improvement

then deceiving people into thinking a fake medicine actually works does no harm

or is ethically justified.

Among the well-known objections to this idea

is that if people come to rely on treatments with no scientific validity

they may fail to pursue treatments that would be effective.

But a 2010 study by Ted Kaptchuk and his colleagues

indicates that the placebo effect may work even when you know it's a placebo.

They divided IBS patients into two groups.

One received no treatment; the other was given dummy pills twice daily

and told the pills had no active ingredient.

The word 'placebo' was even printed on the pill bottle.

And yet the study's results showed that the group who knew

they were taking placebos had significantly greater relief from their symptoms

than the no-treatment group.

As Kaptchuk points out, there may be a benefit simply in the performance

of a medical ritual. More research is needed in this area

but anything that might help to rid us of medical deception

would seem to be worthwhile.

As a child, I was brought up to think there was a divine creator of the universe

that listened and responded to prayers.

If I prayed and nothing happened

I was told I must have prayed for the wrong thing

or didn't pray hard enough

or that my prayer was answered but in an indirect way I'd discover later.

I eventually worked out that a god that moved so mysteriously

I had no idea what it had actually done, may as well not be there at all.

Ann prays she'll find a parking space in town. She finds one.

Was her prayer answered, or was it too trivial a request to make of a god

and just a happy coincidence she got her space?

If it's coincidence in this case, why not in others?

On what basis do people rule out coincidence?

Careful analysis or unreliable intuition?

Ben's daughter suddenly stops breathing. He prays she'll be okay

until the ambulance arrives. She dies.

Are we meant to believe Ben's prayer wasn't good enough?

Or that there was a different divine plan for him and the child?

If our fates are already divinely decided

then prayer would have no effect even if gods existed.

Big problems arise when superstitions get so well-established

that any outcome reinforces them.

So if you pray, dance for rain or put on what you think is a lucky hat

then get the results you want, you go on praying, dancing, or wearing the hat.

But if you don't get the desired results, you still pray, dance or wear the hat

certain that it will work for you again. In this way

you create a bias towards confirming the causal connection you've made

and a blindness to conflicting information

that would help you identify your mistake.

Once that happens, you've built a barrier to rational thinking

and you've departed from reality.

Like Skinner's pigeons, you're left flapping about

in a psychological cage of your own making

blocked from realising your actions are not having the effect you imagine.

If we find Skinner's pigeons quaint and amusing;

if we find ourselves thinking, "If only they could understand";

how much more should we, with our much greater intelligence

be prepared to examine our own behaviour and confront the false beliefs

that are literally getting us nowhere?

Superstitions can give some a comforting illusion

that they have more control in their life than they actually do.

But their effects can be more oppressive

especially when the superstitious insist

that others share or support these irrational beliefs.

We might know people whose reaction when we put new shoes on a table

or open an umbrella indoors

is clearly designed to make us stop the 'unlucky' behaviour

and thereby validate their magical thinking.

This is one way in which superstitions extend their tyrannical grasp

beyond the believer, and we do well to resist this kind of manipulation.

If some are happy to let evidence-free beliefs rule their lives, so be it.

But they've no right to expect the collaboration of others.

When you reject superstition, you no longer feel protected by good luck charms

but you also stop worrying about black cats and broken mirrors.

Holy water can't bless you, but curses can't harm you.

Crystals or homoeopathy may not improve your health

but you'll also be less vulnerable to psychological and financial exploitation

from medical charlatans.

You can't control people with magic rituals

but they can't do the same to you.

Perhaps most importantly, good and evil supernatural forces

no longer get the credit or blame for what human beings do.

Instead it can be clearly understood that people are responsible

for their own kindness, cruelty, generosity, meanness, laziness or hard work.

Owning responsibility can give a sense of genuine self-control

but it does mean learning from mistakes.

When we follow superstitions, our mistakes become invisible to us

because we've already mixed them into our whole way of thinking.

If we tell ourselves magic can solve our problems

or rid us of guilt for any wrong we do, that's a much easier ride

than thinking critically or holding ourselves accountable.

But if the price is denying reality, becoming fearful of knowledge,

being unable to distinguish true and false claims, or demonizing difference

it's worth considering the possibility that that easy ride

will cheat you out of much more in the long run.

With a little careful, critical thought

we can identify our own cages of superstition

and walk free of them.