Recall in acoustically similar and dissimilar letters by normal and deaf subjects.

Stimulus matrices with 4 X 3 letters from an acoustically similar and dissimilar alphabet were presented tachystoscopically for 5 secs to 41 Ss divided into three groups, i.e. normal and deaf apprentices and deaf children. Each S was administered 42 stimulus matrices. While the difference in the number of errors between the acoustically similar and dissimilar alphabets proved significant in the hearing Ss, it was nonsignificant in the deaf, and in contrast to these two groups, in the children the number of errors with the acoustically similar alphabet was lower than with the dissimilar one. The error matrices indicate a systematic course of errors and their different pattern for the hearing and the deaf Ss. A visual and an articulating code which is reinforced by the length of oral training, may be presumed particularly in the deaf.