These pages demonstrate an experiment concerned with the perception of vowels. You heard a voice saying "Please say what this word is:" followed by a test word which is one of the words "bit, bet, bat, but".
Most people identify
The first word is just for practice. The point of the experiment is that the second and third words are actually identical. It is the introductory sentence "Please say what this word is" that alters, making the vowels in the last two test words sound different, because they are judged relative to those in the introductory sentence.
The auditory effect demonstrated on the previous page was first reported in: Peter Ladefoged and Broadbent, Donald (1957) "Information conveyed by vowels," Journal of the Acoustical Society of America. 29, 98-104. The stimuli used on the previous page are similar to those reported in: Peter Ladefoged (1989) "A note on 'Information conveyed by vowels'." Journal of the Acoustical Society of America, 85, 2223-4.
These web pages allow you to reproduce part of the original experiment. Note that it uses speech synthesized in 1955. Click here to hear the original experiment.