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4.1 Stimulus Presentation Considerations
The stimulus presentation protocol is an important experimental design consideration in determining the appropriate techniques to be used to assess fi sh hearing.
The number of stimulus presentations required to accurately determine thresholds
or positive responses differs between stimulus presentation methods. Unlike electrophysiological methods such as the AEP recording technique, which can show
changes in response amplitude or rate, behavioral methods often have binomial outcomes (response or no response). Therefore, the appropriate stimulus presentation
method used will be important in order to minimize the number of trials required to
accurately estimate the parameters of interest (e.g., auditory threshold). The three
major classes of stimulus presentation methods are the method of constant stimuli,
the method of limits, and adaptive procedures (Gescheider 1997 ). Although the
theory behind these techniques is beyond the scope of this chapter, we invite the
reader to consider the underlying assumptions of these procedures before implementation (Jesteadt 1980 ; Fay 1988 ).
4.2 Method of Constant Stimuli
The oldest and most common presentation paradigm currently used in fi sh hearing
studies is the method of constant stimuli, characterized by a randomized set of
parameters (in the case of absolute thresholds, these would be sound level and frequency). This method helps span the entire range of testable parameters and the full
range of the psychometric function required to estimate auditory threshold, but
unfortunately this method often requires a large number of stimulus presentations.
In the larval zebrafi sh ASR and PPI experiments, the method of constant stimuli has
been used to explore the entire frequency detection bandwidth (Zeddies and Fay
2005 ; Bhandiwad et al. 2013 ). This method works because the large number of fi sh
(replicates) being tested at one time reduces the number of total trials required to
determine the probability of an evoked response, but requires a relatively large number of individuals. This method has also been used in studies of frequency discrimination (Fay 1992 ). For example, fi sh conditioned to one frequency can be given a
randomized frequency from a set of test frequencies and the probability of observing the unconditioned response can be modeled using a psychometric function.
4.3 Method of Limits
The method of limits is a paradigm by which stimuli are presented in an ascending
or descending order until the behavior of interest is either present or absent, respectively. This procedure is repeated multiple times and the derived thresholds are
Revisiting Psychoacoustic Methods for the Assessment of Fish Hearing
4.1 Stimulus Presentation Considerations
The stimulus presentation protocol is an important experimental design consideration in determining the appropriate techniques to be used to assess fi sh hearing.
The number of stimulus presentations required to accurately determine thresholds
or positive responses differs between stimulus presentation methods. Unlike electrophysiological methods such as the AEP recording technique, which can show
changes in response amplitude or rate, behavioral methods often have binomial outcomes (response or no response). Therefore, the appropriate stimulus presentation
method used will be important in order to minimize the number of trials required to
accurately estimate the parameters of interest (e.g., auditory threshold). The three
major classes of stimulus presentation methods are the method of constant stimuli,
the method of limits, and adaptive procedures (Gescheider 1997 ). Although the
theory behind these techniques is beyond the scope of this chapter, we invite the
reader to consider the underlying assumptions of these procedures before implementation (Jesteadt 1980 ; Fay 1988 ).
4.2 Method of Constant Stimuli
The oldest and most common presentation paradigm currently used in fi sh hearing
studies is the method of constant stimuli, characterized by a randomized set of
parameters (in the case of absolute thresholds, these would be sound level and frequency). This method helps span the entire range of testable parameters and the full
range of the psychometric function required to estimate auditory threshold, but
unfortunately this method often requires a large number of stimulus presentations.
In the larval zebrafi sh ASR and PPI experiments, the method of constant stimuli has
been used to explore the entire frequency detection bandwidth (Zeddies and Fay
2005 ; Bhandiwad et al. 2013 ). This method works because the large number of fi sh
(replicates) being tested at one time reduces the number of total trials required to
determine the probability of an evoked response, but requires a relatively large number of individuals. This method has also been used in studies of frequency discrimination (Fay 1992 ). For example, fi sh conditioned to one frequency can be given a
randomized frequency from a set of test frequencies and the probability of observing the unconditioned response can be modeled using a psychometric function.
4.3 Method of Limits
The method of limits is a paradigm by which stimuli are presented in an ascending
or descending order until the behavior of interest is either present or absent, respectively. This procedure is repeated multiple times and the derived thresholds are
Revisiting Psychoacoustic Methods for the Assessment of Fish Hearing