0:00:06.760,0:00:09.160
Are you afraid of black cats?

0:00:09.160,0:00:11.890
Would you open an umbrella indoors?

0:00:11.890,0:00:15.552
And how do you feel about [br]the number thirteen?

0:00:15.552,0:00:17.299
Whether or not you believe in them,

0:00:17.299,0:00:20.650
you're probably familiar with a few[br]of these superstitions.

0:00:20.650,0:00:23.600
So how did it happen that people[br]all over the world

0:00:23.600,0:00:25.200
knock on wood,

0:00:25.200,0:00:28.749
or avoid stepping on sidewalk cracks?

0:00:28.749,0:00:31.711
Well, although they have no basis[br]in science,

0:00:31.711,0:00:35.020
many of these weirdly specific beliefs[br]and practices

0:00:35.020,0:00:39.400
do have equally weird[br]and specific origins.

0:00:39.400,0:00:41.850
Because they involve supernatural causes,

0:00:41.850,0:00:45.501
it's no surprise that many superstitions[br]are based in religion.

0:00:45.501,0:00:50.550
For example. the number thirteen was[br]associated with the biblical Last Supper,

0:00:50.550,0:00:53.682
where Jesus Christ dined [br]with his twelve disciples

0:00:53.682,0:00:57.720
just before being arrested and crucified.

0:00:57.720,0:01:02.462
The resulting idea that having thirteen[br]people at a table was bad luck

0:01:02.462,0:01:08.142
eventually expanded into thirteen[br]being an unlucky number in general.

0:01:08.142,0:01:12.821
Now, this fear of the number thirteen,[br]called triskaidekaphobia,

0:01:12.821,0:01:18.262
is so common that many buildings around [br]the world skip the thirteenth floor,

0:01:18.262,0:01:22.102
with the numbers going straight from[br]twelve to fourteen.

0:01:22.102,0:01:26.361
Of course, many people consider[br]the story of the Last Supper to be true

0:01:26.361,0:01:29.360
but other superstitions come from [br]religious traditions

0:01:29.360,0:01:33.033
that few people believe in[br]or even remember.

0:01:33.033,0:01:37.793
Knocking on wood is thought to come from [br]the folklore of the ancient Indo-Europeans

0:01:37.793,0:01:40.733
or possibly people who predated them

0:01:40.733,0:01:44.253
who believed that trees were home[br]to various spirits.

0:01:44.253,0:01:46.677
Touching a tree would invoke [br]protection

0:01:46.677,0:01:50.107
or blessing of the spirit within.

0:01:50.107,0:01:52.372
And somehow,

0:01:52.372,0:01:56.197
this tradition survived long after [br]belief in these spirits had faded away.

0:01:56.197,0:02:00.237
Many superstitions common today[br]in countries from Russia to Ireland

0:02:00.237,0:02:05.813
are thought to be remnants of the pagan[br]religions that Christianity replaced.

0:02:05.813,0:02:08.693
But not all superstitions are religious.

0:02:08.693,0:02:13.313
Some are just based on unfortunate[br]coincidences and associations.

0:02:13.313,0:02:16.453
For example many Italians fear[br]the number 17

0:02:16.453,0:02:23.284
because the Roman numeral XVII[br]can be rearranged to form the word vixi,

0:02:23.284,0:02:25.633
meaning my life had ended.

0:02:25.633,0:02:27.754
Similarly, the word for the number four

0:02:27.754,0:02:30.494
sounds almost identical [br]to the word for death

0:02:30.494,0:02:32.044
in Cantonese,

0:02:32.044,0:02:33.774
as well as languages like Japanese

0:02:33.774,0:02:37.705
and Korean that have borrowed [br]Chinese Numerals.

0:02:37.705,0:02:41.274
And since the number one also[br]sounds like the word for must,

0:02:41.274,0:02:45.383
the number fourteen sounds[br]like the phrase must die.

0:02:45.383,0:02:50.294
That's a lot of numbers for elevators[br]and international hotels to avoid.

0:02:50.294,0:02:51.414
And believe it or not,

0:02:51.414,0:02:53.994
some superstitions actually make sense,

0:02:53.994,0:02:58.174
or at least they did until we [br]forgot their original purpose.

0:02:58.174,0:03:03.185
For example, theater scenery used to[br]consist of large painted backdrops,

0:03:03.185,0:03:07.925
raised and lowered by stagehands[br]who would whistle to signal each other.

0:03:07.925,0:03:11.325
Absentminded whistles from other people[br]could cause an accident.

0:03:11.325,0:03:16.694
But the taboo against whistling backstage[br]still exists today,

0:03:16.694,0:03:20.576
long after the stagehands started using[br]radio headsets.

0:03:20.576,0:03:24.345
Along the same lines, lighting three[br]cigarettes from the same match

0:03:24.345,0:03:29.565
really could cause bad luck[br]if you were a soldier in a foxhole

0:03:29.565,0:03:34.586
where keeping a match lit too long[br]could draw attention from an enemy sniper.

0:03:34.586,0:03:37.458
Most smokers no longer have to worry[br]about snipers,

0:03:37.458,0:03:39.636
but the superstition lives on.

0:03:39.636,0:03:42.596
So why do people cling to these bits[br]of forgotten religions,

0:03:42.596,0:03:43.486
coincidences,

0:03:43.486,0:03:45.376
and outdated advice?

0:03:45.376,0:03:48.137
Aren't they being totally irrational?

0:03:48.137,0:03:50.077
Well, yes, but for many people,

0:03:50.077,0:03:54.816
superstitions are based more[br]on cultural habit than conscious belief.

0:03:54.816,0:03:59.027
After all, no one is born knowing to avoid[br]walking under ladders

0:03:59.027,0:04:00.717
or whistling indoors,

0:04:00.717,0:04:04.743
but if you grow up being told[br]by your family to avoid these things,

0:04:04.743,0:04:06.846
chances are they'll make [br]you uncomfortable,

0:04:06.846,0:04:11.208
even after you logically understand[br]that nothing bad will happen.

0:04:11.208,0:04:14.838
And since doing something like knocking[br]on wood doesn't require much effort,

0:04:14.838,0:04:19.946
following the superstition is often[br]easier than consciously resisting it.

0:04:19.946,0:04:23.696
Besides, superstitions [br]often do seem to work.

0:04:23.696,0:04:27.508
Maybe you remember hitting a home run[br]while wearing your lucky socks.

0:04:27.508,0:04:29.947
This is just our psychological [br]bias at work.

0:04:29.947,0:04:33.417
You're far less likely to remember [br]all the times you struck out

0:04:33.417,0:04:35.448
while wearing the same socks.

0:04:35.448,0:04:39.008
But believing that they work[br]could actually make you play better

0:04:39.008,0:04:43.697
by giving you the illusion of having[br]greater control over events.

0:04:43.697,0:04:48.369
So in situations in where that confidence[br]can make a difference, like sports,

0:04:48.369,0:04:52.838
those crazy superstitions might not[br]be so crazy after all.