The human urge to imitate others is so ingrained, that our odds of winning the playground hand game Rock-Paper-Scissors are higher with eyes shut than with eyes open, said University College London (UCL) researchers in a new study published in the Proceedings of the Royal Society B this week.

Before you try to get your head around how the odds of winning Rock-Paper-Scissors can increase with eyes shut, try thinking about it the other way around: what are the odds with your eyes open?

The one-handed game Rock-Paper-Scissors is an old playground favourite all over the world. You and your opponent have to show one of three possible single hand gestures at the same time: either Rock (closed fist), Paper (flat hand), or Scissors (fist with index and middle finger open like scissors). Wins happen when: Rock beats Scissors (because it can crush them), Paper beats Rock (because it can wrap around it), and Scissors beats paper (because they can cut it). Showing the same hand gesture as your opponent is a draw.

So, if both opponents “show their hand” at exactly the same time, one would expect the odds of drawing to be one in three (there are nine possible patterns comprising three of win-lose, three of lose-win, and three of draw-draw).

And this is what the researchers found, but only when both players wore blindfolds. When one of the players was allowed to play without a blindfold, while their opponent still had to wear theirs, the odds of drawing (with eyes open) went up! They just couldn’t help imitating the hand gesture of their blindfolded opponent.

This was despite the fact there was a financial incentive to win.

For their study, lead author Richard Cook, from the UCL Department of Cognitive, Perceptual and Brain Science, and colleagues, recruited 45 volunteers to play the game in one of two conditions: with and without blindfolds.

In the first condition, both players were blindfolded, in the other, only one was blindfolded. Players who won the most games out of 60 in each match were promised a financial reward, giving them an incentive to avoid draws.

Cook and colleagues observed that the number of games ending in a draw in the blind-blind condition was exactly as one might expect by chance: that is one in three. But in the blind-sighted matches the number of games ending in a draw was signficantly higher than a third: the sighted player was copying the hand gesture of their blinfolded opponent, even when it was not in their interest to do so.

Cook told the press:

“From the moment we’re born, we are frequently exposed to situations where performing an action accurately predicts seeing the same action, or vice versa. Parents seemingly can’t help but imitate the facial expressions of their newborns – smiling, sticking their tongues out and so on.”

He said such experiences cause the impulse to imitate “to become so ingrained it is often subconscious, for example when one person starts tapping their foot in a waiting room it is not uncommon for the whole room to start tapping their feet without thinking.”

If it is the case that such hand gesture responses are “automatic”, that is they are not voluntary results of thinking, then for this to happen, the mere sight of the action in one player has to excite the motor “program” for making the same action in the other player almost instantaneously.

There is good evidence that such responses do indeed happen in what is called the “mirror neuron system”: this responds immediately to the sight of an action, thereby introducing a bias toward imitation that has to be overcome if one tries to do something different.

Cook said we have good evidence that these imitative responses occur much faster than non-imitative ones. Experiments have been done with reaction times in the range 200-400 milliseconds.

He said the value of this study is that it shows such imitative responses can be hard to stop, which is why they seem to be “automatic”.

Funds from the Economic and Social Research Council paid for the study.

“Automatic imitation in a strategic context: players of rock-paper-scissors imitate opponents’ gestures.”
Richard Cook, Geoffrey Bird, Gabriele Lünser, Steffen Huck, Cecilia Heyes.
Proc. R. Soc. B, Published online before print 20 July 2011
DOI:10.1098/rspb.2011.1024
Link to Article.

Additional source: UCL.

Written by: Catharine Paddock, PhD