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
Under controlled conditions, most of the subjects identified the first word as "but". 97% of the 60 subjects identified the second word as "bet" & 95% the third word as "bit". As before, the second and third words are actually identical. All that alters is the frequency of the first formant in the introductory sentence "Please say what this word is". The speech was synthesized on PAT (Parametric Artificial Talker), one of the first formant synthesizers, invented by Walter Lawrence in about 1950.