Traditional theories of animal behavior assert that
animal conflict within a species is highly ritualized
and does not vary from contest to contest. This
species-specific model assumes that repetitive use of
(5) the same visual and vocal displays and an absence of
escalated fighting evolved to prevent injury. The
contestant that exhibits the “best” display wins the
contested resource. Galápagos tortoises, for instance,
settle contests on the basis of height: the ritualized
(10) display consists of two tortoises facing one another
and stretching their necks skyward; the tortoise
perceived as being “taller” wins.
In populations of the spider Agelenopsis aperta,
however, fighting behavior varies greatly from contest
(15) to contest. In addition, fighting is not limited to
displays: biting and shoving are common. Susan
Riechert argues that a recently developed model,
evolutionary game theory, provides a closer fit to
A. aperta territorial disputes than does the species-
(20) specific model, because it explains variations in
conflict behavior that may result from varying
conditions, such as differences in size, age, and
experience of combatants. Evolutionary game theory
was adapted from the classical game theory that was
(25) developed by von Neumann and Morganstern to
explain human behavior in conflict situations. In both
classical and evolutionary game theory, strategies are
weighed in terms of maximizing the average payoff
against contestants employing both the same and
(30) different strategies. For example, a spider may engage
in escalated fighting during a dispute only if the
disputed resource is valuable enough to warrant the
risk of physical injury. There are, however, two major
differences between the classical and evolutionary
(35) theories. First, whereas in classical game theory it is
assumed that rational thought is used to determine
which action to take, evolutionary game theory
assumes that instinct and long-term species advantage
ultimately determine the strategies that are exhibited.
(40) The other difference is in the payoffs: in classical
game theory, the payoffs are determined by an
individual’s personal judgment of what constitutes
winning; in evolutionary game theory, the payoffs are
defined in terms of reproductive success.
(45) In studying populations of A. aperta in a
grassland habitat and a riparian habitat, Riechert
predicts that such factors as the size of the opponents,
the potential rate of predation in a habitat, and the
probability of winning a subsequent site if the dispute
(50) is lost will all affect the behavior of spiders in
territorial disputes. In addition, she predicts that the
markedly different levels of competition for web sites
in the two habitats will affect the spiders’ willingness
to engage in escalated fighting. In the grassland,
(55) where 12 percent of the habitat is available for
occupation by A. aperta, Riechert predicts that
spiders will be more willing to engage in escalated
fighting than in the riparian habitat, where 90 percent
of the habitat is suitable for occupation.
1. Which one of the following best states the main idea of the passage?(A) Evolutionary game theory and classical game theory can be used to analyze the process of decision-making used by humans and animals in settling disputes.
(B) A. aperta in grassland habitats and riparian habitats exhibit an unusually wide variety of fighting behaviors in territorial disputes.
(C) Evolutionary game theory may be useful in explaining the behavior of certain spiders during territorial disputes.
(D) The traditional theory of animal behavior in conflict situations cannot be used to explain the fighting behavior of most species.
(E) Evolutionary game theory, adapted from classical game theory, is currently used by scientists to predict the behavior of spiders in site selection.
2. The author of the passage mentions Galápagos tortoises in the first paragraph most likely in order to(A) describe a kind of fighting behavior that is used by only a few species
(B) suggest that repetitive use of the same visual and vocal displays is a kind of fighting behavior used by some but not all species
(C) provide evidence to support the claim that fighting behavior does not vary greatly from contest to contest for most species
(D) provide an example of a fighting behavior that is unique to a particular species
(E) provide an example of a ritualized fighting behavior of the kind that traditional theorists assume is the norm for most species
3. Which one of the following, if true, is LEAST consistent with Riechert’s theory about fighting behavior in spiders?(A) Spiders in the grassland habitat engage in escalated fighting when a disputed site is highly desirable.
(B) Spiders in the riparian habitat are not willing to engage in escalated fighting for less-than suitable sites.
(C) Spiders in the riparian habitat confine their fighting to displays more regularly than do spiders in the grassland habitat.
(D) Spiders in the riparian habitat are as willing to engage in escalated fighting as are spiders in the grassland habitat.
(E) Spiders in the riparian habitat are more likely to withdraw when faced with a larger opponent in territorial disputes than are spiders in the grassland habitat.
4. Which one of the following best states the function of the third paragraph of the passage?(A) It develops a comparison of the two theories that were introduced in the preceding paragraph.
(B) It continues a discussion of a controversial theory described in the first two paragraphs of the passage.
(C) It describes an experiment that provides support for the theory described in the preceding paragraph.
(D) It describes a rare phenomenon that cannot be accounted for by the theory described in the first paragraph.
(E) It describes predictions that can be used to test the validity of a theory described in a preceding paragraph.
5. The passage suggests which one of the following about the behavior of A. aperta in conflict situations?(A) They exhibit variations in fighting behavior from contest to contest primarily because of the different levels of competition for suitable sites in different habitats.
(B) They may confine their fighting behavior to displays if the value of a disputed resource is too low and the risk of physical injury is too great.
(C) They exhibit variations in fighting behavior that are similar to those exhibited by members of most other species of animals.
(D) They are more likely to engage in escalated fighting during disputes than to limit their fighting behavior to visual and vocal displays.
(E) They are more willing to engage in escalated fighting during conflict situations than are members of most other species of animals.
6. The primary purpose of the passage is to (A) present an alternative to a traditional approach
(B) describe a phenomenon and provide specific examples
(C) evaluate evidence used to support an argument
(D) present data that refutes a controversial theory
(E) suggest that a new theory may be based on inadequate research