On the spot: Deciding which way to kick during penalty shoot-out explained by German scientists studying monkeys
The decision which way to kick during nerve-wracking penalty shootouts has been scientifically explained by German researchers studying monkeys.
Two different types of nerve cells in the same brain area are responsible for a taker's decision-making process, according to new research.
And they ensure he is unlikely to change his mind - even if the goalkeeper moves.
Study first author Lalitta Suriya-Arunroj, a PhD student at the German Primate Centre in Göttingen, said: "A preliminary action tendency influences subsequent decisions, even if the facts change in the meantime.
"Even though the monkeys had a free choice, they opted for their provisional plan of action.
"Even if the goalkeeper takes a neutral posture at the last moment, in most cases he will keep this direction and the penalty kick may be intercepted."
In the study, published in the journal eLife, her team trained two rhesus monkeys to perform a task as the activity of the nerve cells in their brain was measured.
Circular signals appeared on a touch pad - either on the right or left and the top or bottom of the screen.
The place where they appeared was random, but the monkeys received a hint in the form of small arrows where the next signal could appear.
For example, if there was a large purple arrow pointing to the left and a small blue arrow pointing to the right at the same time, it was more likely that the signal would appear on the left.
However, this expectation was violated every now and then by the signal appearing exactly opposite the previously indicated direction or by both signals appearing simultaneously on the right and left, which could then be freely selected.
The researchers observed that the monkeys developed a tendency towards the direction indicated by the arrows previously shown.
If the signal appeared on the expected side, they solved the task correctly and quickly. If, contrary to expectations, the signal appeared on the opposite side, the reaction times increased and the monkeys made more mistakes.
If the animals had the free choice, they preferred in most cases those signals, which appeared on the before indicated side, even if both possibilities were objectively considered equivalent.
The study also found decision-making and the weighing between several action alternatives are mapped as a dual process in the brain.
Two different types of nerve cells are responsible - with the first controlling the preferred target. They only fire when a preference for an action option arises.
The second group shows all given alternatives from the beginning. It is decided which of the options for action is out of the question.
The nerve cells that code for the non-preferred option are the more strongly down-regulated the less the option is considered.
According the choice-by-elimination principle, the option that represents the best choice remains.
Study co author Prof Alexander Gail, who is based in the same lab, said: "The fact two different nerve cells in the same brain area are responsible for the decision-making process is a new finding of this study.
"The planning in the brain is thus controlled by a dual process that reflects strong tendencies to act as well as all other possibilities that can be eliminated one after the other by the choice-by-elimination principle. Thus, the brain enables us to make balanced and flexible decisions.
"The striker in front of the goal, despite his first preference, is thus able not to immediately exclude the other corner of the goal as an option, can change the direction of the shot at the last moment and thus possibly still score a goal."