tor integration) has been a major theme of research in the study of birdsong but, except for some work on echolocation (Valentine and Moss 1997),
has been relatively neglected in studies of other communication systems.
Indeed, our knowledge of central motor mechanisms controlling vocal
output is incomplete in many species, and, in spite of the theoretical importance of production/perception linkage, it is still unclear how the outputs of
the different cell types described in central auditory nuclei interact to regulate vocal output.
3.2. Behavioral Analysis
The variability or plasticity, rather than the stereotypy, of signals and messages in communication has recently been emphasized in both theoretical
and experimental work on acoustic communication (Ryan 1990; Ryan and
Keddy-Hector 1992; Fitch and Hauser, Chapter 3). More detailed analysis
of variability in both signals and responses will be important in formulating a coherent phylogenetic view of the evolution of communication (Ryan
and Rand 1990).
Some of the variability seen in both signaler and receiver may be due to
the influence of the social and the sensory environments to which animals
are exposed in their natural habitats. For example, Marler and colleagues
(Marler et al. 1986) have shown that the composition of the social group in
domestic chickens (Gallus gallus) can affect the type and rate of acoustic
signaling. Little quantitative work has examined audience effects in other
vocalizing species. In addition, the influence of other sensory cues (vision,
olfaction, tactile sensation) on the perception or production of acoustic
signals in natural environments has been relatively neglected. Although
experimental designs for teasing out the relative importance of multimodal
signals are available (Partan and Marler 1999), there has to date been little
progress in implementing these designs. Modern video technology should
be exploited to record and quantify the entire sensory environment in
which an animal communicates in order to assess the roles of these other
cues in mediating acoustic behavior (Evans and Marler 1991).
3.3. Ontogeny and Phylogeny
Compared with the extensive literature on songbirds, much less is known
about the development and maturation of acoustic communication in vertebrates that do not appear to learn their vocalizations, even in animals such
as frogs that have been popular models for the study of acoustic communication. Developmental studies in fish and frogs as well as in mammals
can help elucidate mechanisms underlying vocal learning. A study of sensorimotor integration in species that are dependent on vocal learning
compared with those showing more genetic control of vocalizations would
be interesting.
1. Acoustic Communication
11
has been relatively neglected in studies of other communication systems.
Indeed, our knowledge of central motor mechanisms controlling vocal
output is incomplete in many species, and, in spite of the theoretical importance of production/perception linkage, it is still unclear how the outputs of
the different cell types described in central auditory nuclei interact to regulate vocal output.
3.2. Behavioral Analysis
The variability or plasticity, rather than the stereotypy, of signals and messages in communication has recently been emphasized in both theoretical
and experimental work on acoustic communication (Ryan 1990; Ryan and
Keddy-Hector 1992; Fitch and Hauser, Chapter 3). More detailed analysis
of variability in both signals and responses will be important in formulating a coherent phylogenetic view of the evolution of communication (Ryan
and Rand 1990).
Some of the variability seen in both signaler and receiver may be due to
the influence of the social and the sensory environments to which animals
are exposed in their natural habitats. For example, Marler and colleagues
(Marler et al. 1986) have shown that the composition of the social group in
domestic chickens (Gallus gallus) can affect the type and rate of acoustic
signaling. Little quantitative work has examined audience effects in other
vocalizing species. In addition, the influence of other sensory cues (vision,
olfaction, tactile sensation) on the perception or production of acoustic
signals in natural environments has been relatively neglected. Although
experimental designs for teasing out the relative importance of multimodal
signals are available (Partan and Marler 1999), there has to date been little
progress in implementing these designs. Modern video technology should
be exploited to record and quantify the entire sensory environment in
which an animal communicates in order to assess the roles of these other
cues in mediating acoustic behavior (Evans and Marler 1991).
3.3. Ontogeny and Phylogeny
Compared with the extensive literature on songbirds, much less is known
about the development and maturation of acoustic communication in vertebrates that do not appear to learn their vocalizations, even in animals such
as frogs that have been popular models for the study of acoustic communication. Developmental studies in fish and frogs as well as in mammals
can help elucidate mechanisms underlying vocal learning. A study of sensorimotor integration in species that are dependent on vocal learning
compared with those showing more genetic control of vocalizations would
be interesting.
1. Acoustic Communication
11