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D.L. Herzing
2. the individual (intraspecific communication signals-vocal, nonvocal,
nonacoustic, multimodal
3. the society (group rules, eavesdropping, coordination of signals, sound
glances, shared attention and observations, social sonar, acoustic
gazing/body parts
4. the neighbors (interspecific communication signal exchange through
conservation of signals in evolution)
Traditionally, dolphins are thought to use active echolocation to obtain
information from their surroundings, both during limited visibility and
pursuit of a prey item. However, information is likely extracted from listening to, and making sense of, the environment, conspecifics, and neighbors. The detection, decoding, and deciphering of available signals is
dependent on signal-to-noise ratio, critical ratios of hearing, "signature" or
feature information from objects and movement, and developmental (physical and social) stages. It may also include more advanced concepts such as
"auditory scene analysis," as discussed by Bregman (1990). Bregman argues
that the auditory system builds a picture of the world through emergent
perceptions of streams of information. Such streams may include information gleaned from sequential auditory events (such as a series of environmental sounds) or those gleaned from simultaneous spectral information
(such as the timbre of the human voice). In either case, the auditory system
may have evolved these features to order information into natural groupings that make sense in the real world. Such features are regularly found
in the visual system (e.g., size and constancy). As higher-order emergent
perceptual features, sequential and simultaneous processing of information
should be examined in the world of delphinid audition.
Some pertinent qu~stions around delphinid hearing might also include:
1. Does the acoustic mode kick in when vision is lost?
2. Does critical information include silence and space between sounds?
3. Is there redundancy in such a communication system, and, if so, where
does it reside?
4. Does the cessation of calling increase listening and, therefore, detection
abilities (signal-to-noise ratios) versus a steady-stream conspecific noise
to interpret?
5. How do dolphins learn to "hear" and discriminate salient features of
their environment, and are there opportunities to observe this process?
4.1 Detection, Decoding, and Deciphering
4.1.1 Detection
For complex hearing and communication, a dolphin must have the perceptual and cognitive abilities to restrict attention to things of importance in
the environment and reject the rest. Increasingly complex sensory systems
are able to process wide ranges of physical and social data with higher
D.L. Herzing
2. the individual (intraspecific communication signals-vocal, nonvocal,
nonacoustic, multimodal
3. the society (group rules, eavesdropping, coordination of signals, sound
glances, shared attention and observations, social sonar, acoustic
gazing/body parts
4. the neighbors (interspecific communication signal exchange through
conservation of signals in evolution)
Traditionally, dolphins are thought to use active echolocation to obtain
information from their surroundings, both during limited visibility and
pursuit of a prey item. However, information is likely extracted from listening to, and making sense of, the environment, conspecifics, and neighbors. The detection, decoding, and deciphering of available signals is
dependent on signal-to-noise ratio, critical ratios of hearing, "signature" or
feature information from objects and movement, and developmental (physical and social) stages. It may also include more advanced concepts such as
"auditory scene analysis," as discussed by Bregman (1990). Bregman argues
that the auditory system builds a picture of the world through emergent
perceptions of streams of information. Such streams may include information gleaned from sequential auditory events (such as a series of environmental sounds) or those gleaned from simultaneous spectral information
(such as the timbre of the human voice). In either case, the auditory system
may have evolved these features to order information into natural groupings that make sense in the real world. Such features are regularly found
in the visual system (e.g., size and constancy). As higher-order emergent
perceptual features, sequential and simultaneous processing of information
should be examined in the world of delphinid audition.
Some pertinent qu~stions around delphinid hearing might also include:
1. Does the acoustic mode kick in when vision is lost?
2. Does critical information include silence and space between sounds?
3. Is there redundancy in such a communication system, and, if so, where
does it reside?
4. Does the cessation of calling increase listening and, therefore, detection
abilities (signal-to-noise ratios) versus a steady-stream conspecific noise
to interpret?
5. How do dolphins learn to "hear" and discriminate salient features of
their environment, and are there opportunities to observe this process?
4.1 Detection, Decoding, and Deciphering
4.1.1 Detection
For complex hearing and communication, a dolphin must have the perceptual and cognitive abilities to restrict attention to things of importance in
the environment and reject the rest. Increasingly complex sensory systems
are able to process wide ranges of physical and social data with higher