Spondee recognition threshold as a function of set size

Recognition thresholds for spondaic words were obtained in normal listeners under conditions of varying set size. Six sets of spondees were derived from the 36-word corpus of a Northwestern University recording of CID W-1 spondaic words. One of these sets represented the full list of 36 spondees, whereas the remaining five were comprised of 27, 18, 9, 6, and 3 spondees selected to be homogeneous in level and slope characteristics. Results revealed a systematic and reliable effect wherein mean threshold decreased from 19.1 dB SPL to 12.2 dB SPL as set size was reduced from 36 to 3 spondees. The data are consistent with past research on human information processing in that spondee recognition threshold increased linearly with the number of bits per stimulus.