Interactive
exercises also demonstrate experimental techniques. Students can easily perform speech
perception experiments using synthetic speech.
This screen illustrates a stimulus continuum, such as would be used in an
identification or discrimination experiment. The screen shows spectrograms of seven
stimuli. A student can play a stimulus by clicking the loudspeaker of the corresponding
spectrogram. In this example of the ABX paradigm, the stimulus is played after the two
endpoint (the first and seventh) stimuli.
A variety of different experiments in the course use the same stimuli, playing them
alone or in combination. Students respond by clicking the appropriate items on the screen
(e.g., "Same" or "Different") and the computer automatically collects,
tallies, and displays the responses.
After analyzing the data from the student’s experiment, a
discrimination function is plotted on the screen, showing the percentage of times that
each pair of adjacent stimuli was judged different. Each point on the discrimination
function is connected to the corresponding pair of stimuli; the chance response level is
also indicated. Students can compare their performance on the discrimination task to
typical results found in the literature or collected in experimental trials by the course
authors.
Interactivity also allows students to perform "gedanken"
experiments and explore the results. This is particularly useful in evaluating theories of
speech perception. In the screen illustration at the left, two stimulus continua are
presented. The first is a synthetic speech continuum in which the duration of aspiration
varies; the other is a non-speech stimulus continuum in which the duration of a tone
varies. The speech continuum is perceived categorically; the student is asked to predict
whether or not the non-speech continuum will also be perceived categorically. This
student’s response, at the bottom of the screen, is "No" (highlighted in
red).
This
screen shows some consequences of that prediction. The prediction that the non-speech
stimuli are not perceived categorically is shown to be compatible with one theory,
indicated by a check mark, and not with two other theories.
Interactive
exercises also demonstrate experimental techniques. Students can easily perform speech
perception experiments using synthetic speech.
After analyzing the data from the student’s experiment, a
discrimination function is plotted on the screen, showing the percentage of times that
each pair of adjacent stimuli was judged different. Each point on the discrimination
function is connected to the corresponding pair of stimuli; the chance response level is
also indicated. Students can compare their performance on the discrimination task to
typical results found in the literature or collected in experimental trials by the course
authors.
Interactivity also allows students to perform "gedanken"
experiments and explore the results. This is particularly useful in evaluating theories of
speech perception. In the screen illustration at the left, two stimulus continua are
presented. The first is a synthetic speech continuum in which the duration of aspiration
varies; the other is a non-speech stimulus continuum in which the duration of a tone
varies. The speech continuum is perceived categorically; the student is asked to predict
whether or not the non-speech continuum will also be perceived categorically. This
student’s response, at the bottom of the screen, is "No" (highlighted in
red).
This
screen shows some consequences of that prediction. The prediction that the non-speech
stimuli are not perceived categorically is shown to be compatible with one theory,
indicated by a check mark, and not with two other theories.