Some recent abstracts and pdf files associated with them as well as other recent presentations/posters are listed to the right.
The abstracts and presentations concern informational masking experiments. The task is to detect a tone added to a multi-tone masker (the sum of six tones in these cases). This is very hard (high signal intensities required) when the maskers are randomly drawn on every presentation (c.f., Neff and Green, 1987, Perception and Psychophysics, vol. 41), even though the signal frequency does not change.
When the signal or masker is previewed prior to a trial, threshold signal levels can be substantially lower than when there is no pre-trial cue.
Here are three sound demos in Windows Media Player format (WMA). For all three demos there are five example trials, and the signal is always present. The signals and maskers are the same in all three demos. Initially the signal level is low, and it is increased in level using 4 dB steps.
When can you hear the signal? You might want to listen twice. (But be sure not to play this too loud!)
In this case each trial is a single sound. Can you hear the signal in all five sounds? If not, how many?
In this case each trial has two sounds. The first sound of each pair is the signal. The second sound of each pair is a signal-plus-masker stimulus. Notice that as the signal level is changed, it is apparent in the pre-trial signal presentation. Can you hear the signal when the masker is present? For all five trials?
In this case each trial has two sounds. The first sound is preview of the masker to be tested. The second sound of each pair is the signal-plus-masker stimulus. Can you hear the signal in all five sounds? If not, how many?