Home Research Who touched the ball last? Neuroscience finally solves this basketball dilemma

Who touched the ball last? Neuroscience finally solves this basketball dilemma

Who touched the ball last before it went out of bound? Our brain systematically interprets that we touch first by a cognitive bias that has just been identified.

This dilemma seems to happen all the time in basketball. There is a disputed ball on who of the two opposing players touched it with the tips of their fingers before it goes out of bound. Both players believe that it has been the other who has touched last, to the point that whoever loses possession gets angry with great fuss. And it can happen several times in the same game with different players.

Are we systematically wrong about the tempo of our own actions?

This is the starting point for Ty Tang and his team at Arizona State University (ASU) who wanted to investigate if there is any psychological bias that leads players, and any of us, into thinking that we have taken an action, such as touch the ball, before others. In a paper published in the journal Science Advances, Tang and his colleagues describe the three types of tests they put into practice with several volunteers to check if this bias existed.

Robert Ewing first experiment subjects. Image source: Arizona State University

In the first experiment, two volunteers sat face to face with their hands outstretched and a screen in between blocking them from seeing each other’s faces. When a light signal was switched on, both subjects had to press a finger on one sensor placed on top of the other’s hand and later touch a button if they thought they had done it faster than the other. Each pair repeated this action 50 times and the light signal was switched on with random time differences to prevent mechanical movements. Most of the subjects claimed to have been the first to give to the other even when both had played at the same time or the other had given in their hand 50 milliseconds before.

The result was overwhelming: the volunteers always believed they had done the action first

In a second test, the volunteers repeated the experiment, but this time facing a mechanical device as the other subject. And a beep was included, as a different sensory stimulus, whether they touched first or a beep sounded first.  And the result was overwhelming: in all three scenarios, the volunteers believed they had touched first, even if it was not true and there was a slight delay (50-millisecond) between the touch or beep and when the subjects sensed it.

“Our brains tell us that actions generated by ourselves happen before simultaneous external events,” the authors conclude. “In summary, we have identified what could be the main cause of the fight in ball games.”

“This 50-millisecond delay makes a lot of sense because we know that our brain is always predicting our actions and perceptions, ” explains Michael McBeath, co-author of the study. “People are usually accurate in real-time perception of their own actions, like hitting or catching a baseball, but we need a little extra time to process something that is not planned, like an unexpected blow to the shoulder. When something is unexpected, there is a small perceptual delay while the brain realizes what has happened. ”

“What was once considered deception or mistake has now been brought to the field of basic neuroscience”

This bias would explain the difference in the perception of the same event in situations like we described, in addition to other experiences related to external stimuli. These results could be used to design better automatic assistance devices for humans, such as those that act to slow down cars or to assist refereeing systems in matches.” I hope that as we find more evidence and reasons why we experience things differently, people understand better than others that they have a different experience about the world and about how things happen,” Tang says.

For neuroscientist David Eagleman, who widely researched the perception of time in the brain, it is a brilliant study that focuses on those moments that sports fans contemplate every day. “What was previously considered deception or mistake,” he concludes, “has now been brought into the realm of basic neuroscience.”

This study was funded by Arizona State University and the Global Sport Institute at ASU.

Reference: Who hit the ball out? An egocentric temporary order bias (Science Advances) DOI: 10.1126 / sciadv.aav5698

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