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behavior is the capacity to assign all acoustic components to their appropriate
sources, and not to confuse the components from multiple independent sources with
a single source. This capability is known as the capacity for “source segregation” as
specifically demonstrated for humans (Bregman 1990), European starlings (Hulse
et al. 1997), and goldfish (Fay 1998, 2000). Source segregation is a fundamental
component of “auditory scene analysis,” a proposed model for the basis of auditory
perception where the listener parses the “acoustic ambience” or the mixtures of
sounds into specific, independent sources (biotic and abiotic alike), analogous to a
visual scene (Bregman 1990). By definition, everything in the auditory scene is
biologically significant to the extent that the components of abiotic noise, for example, must be segregated from biotic communication sounds in order for the communication signals to be properly interpreted.
A component of source segregation is sound source localization. Evidence suggests that the capacity for sound source localization is common to mammals, birds,
reptiles, and amphibians (Grothe et al. 2010). Sound source localization gives the
scene a spatial dimension, making it comparable to the visual scene. Surprisingly,
it is not known whether fishes locate sound sources in the same manner (e.g., combining binaural and monaural cues) or what computational strategies they use for
successful source localization (Fay 2005). Sound source localization has been difficult to conceive of for fishes because they are assumed not to use the same binaural acoustic cues as terrestrial animals for the localization of sound sources. In fish,
the two ears (e.g., saccules, which are the main organ of hearing in most fishes) are
not stimulated independently and the interaural time difference (ITD) and interaural level difference (ILD) cues are too small to be utile for source localization.
Furthermore, acoustic particle motion, not sound pressure, is required to stimulate
the ears of fish directly and in a directional manner (Fay 1984; Edds-Walton et al.
1999). In addition to these considerations, the dominant theories for sound source
localization by fishes, e.g., the “phase” model by Schuijf (1975) and the computational model by Rogers et al. (1988), are rather complex and many fish species
seem to lack the ability to detect the acoustic cues (i.e., sound pressure) that are
theoretically necessary (see Sect. 3 in Models of Directional Hearing and Sound
Localization). Thus, the question of how fish locate sound sources remains an open
one. Directional hearing and sound source localization in fishes continues to be
important topics in the neuroethology and evolutionary biology of hearing, but the
empirical and theoretical work on these topics have been contradictory and obscure
for decades.
This review summarizes the previous behavioral work on directional hearing and
sound source localization in fishes and the most recent experiments on source localization in the plainfin midshipman fish, Porichthys notatus, which has proven to be
an exceptional species for fish studies of sound localization. In addition, we also
review the theoretical models of directional hearing and sound source localization
in fishes, and discuss new directions for future research.
J.A. Sisneros and P.H. Rogers
behavior is the capacity to assign all acoustic components to their appropriate
sources, and not to confuse the components from multiple independent sources with
a single source. This capability is known as the capacity for “source segregation” as
specifically demonstrated for humans (Bregman 1990), European starlings (Hulse
et al. 1997), and goldfish (Fay 1998, 2000). Source segregation is a fundamental
component of “auditory scene analysis,” a proposed model for the basis of auditory
perception where the listener parses the “acoustic ambience” or the mixtures of
sounds into specific, independent sources (biotic and abiotic alike), analogous to a
visual scene (Bregman 1990). By definition, everything in the auditory scene is
biologically significant to the extent that the components of abiotic noise, for example, must be segregated from biotic communication sounds in order for the communication signals to be properly interpreted.
A component of source segregation is sound source localization. Evidence suggests that the capacity for sound source localization is common to mammals, birds,
reptiles, and amphibians (Grothe et al. 2010). Sound source localization gives the
scene a spatial dimension, making it comparable to the visual scene. Surprisingly,
it is not known whether fishes locate sound sources in the same manner (e.g., combining binaural and monaural cues) or what computational strategies they use for
successful source localization (Fay 2005). Sound source localization has been difficult to conceive of for fishes because they are assumed not to use the same binaural acoustic cues as terrestrial animals for the localization of sound sources. In fish,
the two ears (e.g., saccules, which are the main organ of hearing in most fishes) are
not stimulated independently and the interaural time difference (ITD) and interaural level difference (ILD) cues are too small to be utile for source localization.
Furthermore, acoustic particle motion, not sound pressure, is required to stimulate
the ears of fish directly and in a directional manner (Fay 1984; Edds-Walton et al.
1999). In addition to these considerations, the dominant theories for sound source
localization by fishes, e.g., the “phase” model by Schuijf (1975) and the computational model by Rogers et al. (1988), are rather complex and many fish species
seem to lack the ability to detect the acoustic cues (i.e., sound pressure) that are
theoretically necessary (see Sect. 3 in Models of Directional Hearing and Sound
Localization). Thus, the question of how fish locate sound sources remains an open
one. Directional hearing and sound source localization in fishes continues to be
important topics in the neuroethology and evolutionary biology of hearing, but the
empirical and theoretical work on these topics have been contradictory and obscure
for decades.
This review summarizes the previous behavioral work on directional hearing and
sound source localization in fishes and the most recent experiments on source localization in the plainfin midshipman fish, Porichthys notatus, which has proven to be
an exceptional species for fish studies of sound localization. In addition, we also
review the theoretical models of directional hearing and sound source localization
in fishes, and discuss new directions for future research.
J.A. Sisneros and P.H. Rogers