Pattern identification of pure tones and frequency glides by untrained listeners

Six subjects identified the order of four-event sequences. Contiguous pure tones (713, 1,031, 1,209, and 1,514 Hz in permuted orders) were presented by earphones at 40 dB SL, with individual events Itones) from 20, to 40, 60, and 300 msec in duration. Again, silent intervals of 20 or 60 msec were inserted among tones of 20 or 40 msec duration. Finally, the pure tones of 713 and 1,209 Hz were combined, in any four-event sequence, with two glissandi chosen from 466 to 714 Hz, from 714 to 1,208 Hz, and their mirror reversals. The temporal and frequency continuity both of tonal and of glissando-plus-tonal sequences affected the identification of sequential order. Degraded performance in the glissando-plus-tonal condition was attributed partially to a subjective experience of pitch blurring. The inclusion of silent intervals in the sequences of the shorter pure-tone durations improved identification performance to that of contiguous sequences of equal overall duration, i.e., adding silent processing time was as efficacious as increasing by the same amount the duration of the individual frequency event.