Referees in this weekend's soccer A-League final series would do well to read the work of Australian scientists into deception before taking the pitch.
The study by University of Queensland researchers shows soccer players are more likely to "take a dive" when a game is drawn and they are near the attacking end, in the hope of securing a penalty.
Co-author Dr Robbie Wilson says the work, published in PLos One, grew out of studies into the evolution of deception.
"One of the difficulties in studying deception in humans is it is hard to identify - by its very nature [deception] is supposed to go undetected," he says.
"We realised professional football gave us a unique opportunity [to look at human deception] as there are so many cameras recording the game it is obvious when a player is not touched and rolls around.
"This is then a clear case of someone trying to deceive another person."
For the work, lead author Gwendolyn David, a PhD student, analysed falls from 60 games - 10 each from the Spanish, German, Dutch, Italian, French and Australian leagues - to determine whether they were "dives".
The falls were then classed as legitimate, slightly deceptive - where the player was touched by an opponent but they exaggerated the impact - or highly deceptive.
She also examined where the falls occurred, the time in the game and the score at the time.
Wilson says only 6 per cent (169) of the 2803 falls observed were dives with the rest (2633) considered legitimate.
He says on average 33 per cent of dives were "rewarded" by the referee with a penalty.
"There is an 80 per cent chance of scoring a goal from a penalty and the study shows players are ruthless in their ability to realise that, and that's why they are doing most of the dives in the penalty area," says Wilson.
He says the study also shows if referees in a league are more likely to give a free kick the players in that league are more likely to dive more often.
Punishing the practice
Wilson says under theories about the evolution of dishonesty the mechanism that controls deception is the likelihood and importance of punishment.
He says in their study sample not a single player was punished.
"Even though these actions can affect a game or a championship, the primary way the referee can stamp 'dives' out of the game - a red or yellow card - is not being used."
Wilson says the Australian and US leagues have recently moved to end the practice by starting to retrospectively punish divers.
"The two leagues will go back and check videotape after game and if [a player is] found guilty of diving they will get suspended," he says.
According to Wilson, the change in policy is having a major impact on the rate of dives.
"At this stage it is only anecdotal, but it appears the numbers of dives has decreased substantially just by making the cost [to the player] greater."
Wilson says he is not surprised the administrators of soccer in Australia and the US have been the first to take action.
"In those countries the game is competing against far more physical codes of football - and the fans have no patience for these antics."
He says the findings of the human-based deception study fit perfectly with deception behaviours in the animal world.
"They really are just a bunch of animals running around the sporting field - they have the same simple motivations of scoring a goal and are affected by the possible cost of their behavioural actions."