to individuality and context, and can they be perturbed so that false alarm
calls are no longer effective?
All of the work described thus far focuses on animals using alarm calls
to deceive others during competitive interactions over food or mates.
Domestic chickens, however, deceive each other in the context of mating
opportunities by producing food calls in the absence of food. Marler and
his colleagues (Marler et al. 1986a, 1986b) first showed that roosters
produce characteristic vocalizations when they discover food, with the rate
of call production positively correlated with food quality. They further
observed that roosters give food calls in the absence of food and are most
likely to do so when a female is present; roosters are silent when another
rooster is nearby, regardless of the presence or absence of food.
One explanation for the chicken’s calling behavior is that rather than providing external reference by calling attention to food, the call reflects the
signaler’s willingness to engage in social interactions. In other words, chickens might often call in the context of food, but the call does not refer to
food but to something more general. To explore whether food-associated
calls refer to food or to the intent to engage in social interactions, Marler
and his colleagues (Marler et al. 1986a, 1986b, 1991; Gyger and Marler 1988;
Evans and Marler 1994, 1995) carried out experiments with chickens living
in a seminaturalistic environment. If food-associated calls refer to food,
then calls produced in the absence of food would represent lies of commission. Results showed that 45% of all calls were produced with no identifiable object present. When calls were produced in the presence of food,
changes in call rate were related to food quality but not to the distance
between mates or the probability of performing the waltzing display, a
behavior used by males as an invitation to mate. In an experiment using an
operant procedure, males pecked for food most when a light indicated that
food was available. Food calling was considerably lower when the light was
off, even when a receptive female was present; waltzing was highest when
the female was first introduced. These two experiments suggest that the call
refers to food even though it is mediated by social context.
Given that the call refers to food, its production in the absence of food
appears to represent a case of deception. Support for this claim comes from
looking at the relationship between food-call production and interindividual distance. Males were more likely to produce food calls in the absence
of food when the females were far away than when they were close. This
makes sense if a male’s vocal behavior is sensitive to the female’s visual
perspective and, in particular, the probability that she will notice the
absence of food. Thus, males should call honestly if females are sufficiently
close that they can see whether the male does or does not have food. In
contrast, they should act deceptively when females are sufficiently far away
to prevent a clear view of the potential feeding area.
To function as a deceptive signal, calls produced in the absence of food
must sound like those produced in the presence of food and must have an
3. Unpacking “Honesty”
113
calls are no longer effective?
All of the work described thus far focuses on animals using alarm calls
to deceive others during competitive interactions over food or mates.
Domestic chickens, however, deceive each other in the context of mating
opportunities by producing food calls in the absence of food. Marler and
his colleagues (Marler et al. 1986a, 1986b) first showed that roosters
produce characteristic vocalizations when they discover food, with the rate
of call production positively correlated with food quality. They further
observed that roosters give food calls in the absence of food and are most
likely to do so when a female is present; roosters are silent when another
rooster is nearby, regardless of the presence or absence of food.
One explanation for the chicken’s calling behavior is that rather than providing external reference by calling attention to food, the call reflects the
signaler’s willingness to engage in social interactions. In other words, chickens might often call in the context of food, but the call does not refer to
food but to something more general. To explore whether food-associated
calls refer to food or to the intent to engage in social interactions, Marler
and his colleagues (Marler et al. 1986a, 1986b, 1991; Gyger and Marler 1988;
Evans and Marler 1994, 1995) carried out experiments with chickens living
in a seminaturalistic environment. If food-associated calls refer to food,
then calls produced in the absence of food would represent lies of commission. Results showed that 45% of all calls were produced with no identifiable object present. When calls were produced in the presence of food,
changes in call rate were related to food quality but not to the distance
between mates or the probability of performing the waltzing display, a
behavior used by males as an invitation to mate. In an experiment using an
operant procedure, males pecked for food most when a light indicated that
food was available. Food calling was considerably lower when the light was
off, even when a receptive female was present; waltzing was highest when
the female was first introduced. These two experiments suggest that the call
refers to food even though it is mediated by social context.
Given that the call refers to food, its production in the absence of food
appears to represent a case of deception. Support for this claim comes from
looking at the relationship between food-call production and interindividual distance. Males were more likely to produce food calls in the absence
of food when the females were far away than when they were close. This
makes sense if a male’s vocal behavior is sensitive to the female’s visual
perspective and, in particular, the probability that she will notice the
absence of food. Thus, males should call honestly if females are sufficiently
close that they can see whether the male does or does not have food. In
contrast, they should act deceptively when females are sufficiently far away
to prevent a clear view of the potential feeding area.
To function as a deceptive signal, calls produced in the absence of food
must sound like those produced in the presence of food and must have an
3. Unpacking “Honesty”
113