There is something about primeval about the part of human nature that loves seeing someone falling for a good harmless prank —I certainly have enjoyed pranking my kids over the years, pulling their legs (in a cheerful, happy way, just to keep them on their toes. That’s what makes April Fools’ one of our favourite days of the year. Scientists have found that many of the great apes like to playfully tease, prank and play with each other just like humans. In their case this can include hair-pulling, poking and body slamming other members of their group as well as waving objects repeatedly in front of their faces [1].

In humans we have even identified a day for fooling that underscores how important surprises are for our brains. Of course, we might hope those surprises are good/nice ones! Your brain is a bit too smart at ‘joining the dots’ and jumping rapidly to strong conclusions. Making speedy decisions on the basis of limited evidence has been a key to our survival on the planet. It’s one of humankind’s greatest strengths — and weaknesses. We’re continuously making quick decisions. But, sometimes, your brain is a little too quick, and a little too decisive, and there sits the trap.

Non-human primates may enjoy watching someone else trip on a banana peel, according to research on laughter, which found that apes might appreciate slapstick humour. This field of study also helps to explain the origins of laughter and the social aspects of our behaviour. If all is in good clean fun, the discovery of being led down the garden path can be almost as much fun for the ‘victim’ as for the ‘perpetrator!’

Brain Chemistry When You’re Fooled

Your brain releases a variety of ‘modulatory transmitters’ (chemicals that act on your brain in a positive way), whenever you are (pleasantly) surprised. For example, norepinephrine and acetylcholine flood the brain whenever something unexpected or novel occurs. If it's a considered a positive or delightful surprise — as it is when you discover that you’ve been the successful perpetrator or recipient of a clever and harmless practical joke — you feel rewarded, and your brain also releases dopamine.

You might say that the release of norepinephrine is all about ‘turning up the lights,’ to sharpen your attention, given that something unexpected has just occurred. Acetylcholine supports your brain’s recording and remembering of the event, which will help assure that you won’t be so easily fooled next time! Release of dopamine amplifies your ‘happy delight.’ The combined effects of the emotional cocktail are a large part of the reason why we enjoy a happy surprise.

Neurochemistry and the endurance of April Fools Day

This chemical cocktail serves in some way to explain why this peculiar little annual event (All Fools Day) — neither religious nor historic — has been celebrated all over the world for a very long time, dating at least back to the 6^th Century BC in Persia. In France, there’s a long held tradition of taping a paper fish onto someone’s back on “Poisson d’Avril” — literally, “April Fish!” In Scotland, they love a practical joke so much, they extend the holiday to include April 2nd. In less frivolous England and Germany, they’re more efficient — all pranks must be completed by noon. No matter what the tradition, it’s all about that special form of foolery that most often results in a “you got me.”

Why We Fall For It

So, why is it the brain gets fooled? We humans have lots of tricks to convince others that something false is true (and vice versa). You may not be convinced by me saying something is so, but, if I can compound enough evidence to build credibility, I may succeed in my deception. Maybe I get another family member to come in on the trick.

Now, you’re caught off guard, because that family member, perhaps your mum or dad, may be a well-known teller of truth. Maybe you adopt a tone of voice, or a turn of phrase, that captures your victim’s imagination, resulting in a wrong turn. Certain people have exceptional skill in misleading others (that that can stimulate healthy cynicism). Magicians do it professionally and have quite a bag of tricks. Your brain is sampling information moment by moment, and in the intervals between those moments — as they deflect your attention, so you don’t see it — magicians can move an elephant across the room.

Mistakes induced by others

It’s relatively easy to fool or be fooled by another person. It’s one of our important strengths and weaknesses. In fact, it may be a key contributor to our development as a broader society. studies suggest that laughter plays an important role in social bonding. Human communities are much larger than those of other primates and hence require more time to be devoted to social maintenance activities. Yet, there is an upper limit on the amount of time that can be dedicated to social demands, and, in nonhuman primates, this sets an upper limit on social group size. It has been suggested that laughter provides the additional bonding capacity in humans by allowing an increase in the size of the “grooming group.” In this study of freely forming laughter groups, we show that laughter allows a threefold increase in the number of bonds that can be “groomed” at the same time. This would enable a very significant increase in the size of community that could be bonded.

Of course, we all make mistake (all the time). Sometimes, we believe strongly in things that are false. People may witness a crime and be sure who did it, but studies have shown that eyewitness testimony is not all that reliable. The development and ready availability of social media on the internet seems fostered the art of gullibility for large numbers of Facebookers. It has clearly shown that we are good at fooling ourselves and holding strong beliefs that are not accurate. Take the concept of Brexit…

Due to revolutionary advances in brain science, and particularly the ability to reduce error rates, we know that we can now sharpen the brain, so that we virtually never will make mistakes (other than perhaps on April Fools’ Day, just to maintain our old traditions).

And, if you believe that… April fool!

References

1. Dezecache G, Dunbar RIM. Sharing the joke: the size of natural laughter groups. Evolution Hum Behav, 2012;6: 775-779