Auditory versus visual practice effects in the intelligibility of words in everyday sentences

The improvement in speech reception from a TV screen was investigated in 15 young adults with normal audition (A) and vision (V) in the A-only and the V-only modes. Trial 1 consisted of 100 key words from Lists A, B, C, D of the Revised CID Everyday Sentences. S wrote down as much of the sentences as was perceived. In the A mode the speech and a white noise both at azimuth 0 degree were both at 65 db SPL. A and V modes were randomized across Ss. After 30 min, Trial 2 repeated Trial 1 exactly. The mean improvement in the A mode was 10.3 percentage points (words) (p less than .01), in the V mode 3.4 points (p less than .05). Improvement in the A mode was significantly (p less than .01) the greater. The r for individual change from Trial 1 to Trial 2 for the A vs the V mode was only +.13 (p much greater than .05). These practice-only effects are comparable to those reported for similar procedures in training (with feedback) in these modes, and call into question the interpretation of the efficacy of such training procedures, and question the advisability of generalizing the effects of training across essentially independent modalities.