MEETINGBRIEFS>>
SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY | 3–7 JANUARY 2011 | SALT LAKE CITY, UTAH
Soccer and the Art of Deception
Time was when footballers (soccer players,
to Americans) prided themselves on playing
tough. They took their knocks and played on
without complaint. But these days it’s common to see a player fake a collision with an
opponent and writhe on the ground in hopes
of getting a free kick. Such “dives” are “very
frustrating to watch,” says Christopher Rose
of James Madison University in Harrisonburg, Virginia, and goals have been scored
and games won on wrongly awarded free
kicks. To Gwendolyn David, Robbie Wilson, and Daniel Ortiz-Barrientos, however,
the deceptive practice provided a unique
research opportunity. Working at the University of Queensland in Brisbane, Australia, they have found empirical support in the
antics of footballers for game-theory predictions about dishonest signals. And they
have come up with ways the game might
be improved. “It’s a very clever way of testing the predictions of signaling theory,” says
Simon Lailvaux, an integrative biologist at
the University of New Orleans in Louisiana.
“Finding a system where you can actually
quantify or categorize deceptive signals is
very exciting.”
Biologists have long argued about how
dishonesty arises and persists in a population. “Game theory suggests that most
signals should be honest”; otherwise, the
receiver of the signal will stop paying attention, Wilson says. Consider the case of the
280
boy who cried wolf too many times. But
trickery can be very beneficial. A fiddler
crab brandishing a supersized claw may
get the mate even though the claw lacks the
muscle needed to be effective. The bottom
line is, if the reward is great enough, there’s
an incentive to fudge the truth.
Game theory predicts that deception
should occur at low frequencies but should
increase in proportion to the benefit as well
as to the degree to which the deceived party
fails to discriminate between real and fake
signals. But these tenets have had mixed support or have not been tested in real organisms, Wilson says. “There are still a lot of
questions to be asked about how dishonesty
can be maintained in a population,” notes
physiologist Gary Wassmer of Bloomsburg
University in Pennsylvania.
Wilson and David, footballers themselves,
decided to examine whether diving conformed to game-theory predictions. David
surveyed falls from 60 games, 10 each from
the Spanish, German, Australian, Dutch, Italian, and French leagues, replaying them on
TV to decide which were dives. She classified them as legitimate, slightly deceptive (the
player was touched by the opponent but exaggerated the consequences), or highly deceptive. She also tracked where the fall occurred
on the field, at what point in the game it happened, the score at the time, and whether it
was an at-home player who fell.
21 JANUARY 2011
Getting to the Guts
Of Tadpole Carnivory
Known in the aquarium trade as Budgett’s
frog, Lepidobatrachus laevis is not your typical tadpole. Most frogs at this early stage
of life are primarily plant eaters, only later
metamorphosing into quick fly catchers.
But from day one, Budgett’s frog is a carnivore, swallowing whatever wiggles by,
including fellow tadpoles. Its gut reflects this
voracious lifestyle: It has a very large, welldefined stomach and a short intestine, quite
the contrast from the long, winding tube of
most tadpoles. Nanette Nascone-Yoder now
knows how it gets that way.
A developmental biologist at North
Carolina State University College of Veterinary Medicine in Raleigh, NasconeYoder reported that the inhibition of a single
developmental signal—retinoic acid—can
yield the carnivorelike gut morphology in a
tadpole species that’s normally mostly vegetarian. That suggests that it didn’t take
much for the Budgett’s frog tadpole to
VOL 331 SCIENCE www.sciencemag.org
Published by AAAS
Downloaded from www.sciencemag.org on January 20, 2011
referees are more easily
tricked by players
pretending to have
been fouled.
CREDIT: THINKSTOCK
Faked fall? Near goals,
As game theory predicts, legitimate falls
far outnumber fake falls, Wilson reported at
the meeting. Only 6% of the 2800 falls were
highly deceptive dives. Players were two to
three times as likely to dive when close to
the goal, where the payoff was huge: Statistics show that there is an 80% chance of
scoring from penalty kicks. Almost none of
the highly deceptive dives resulted in free
kicks against the diver. And referees were
most likely to reward dives that occurred
close to the goals—perhaps because the
players were farther away and the deception
harder to detect, he noted.
“All leagues, and especially those with
higher levels of diving, will want to consider
increasing the frequency at which they punish divers for their deception,” says behavioral
ecologist Timothy Wright of New Mexico
State University in Las Cruces. Wilson also
suggested that more referees could be positioned where dives are most likely to occur.
Rebecca Safran, an evolutionary ecologist at the University of Colorado, Boulder, cautions that the work is really a study
of cultural evolution and not the evolution
of traits with a genetic basis. Nonetheless,
notes Lailvaux, “I think people will be
reading and thinking about this study for a
long time.”
–ELIZABETH PENNISI