Speaker-listener familiarity: parents as judges of delayed speech intelligibility

It has been frequently proposed that one source of bias in intelligibility judgments is whether the judge knows the subject personally. This study attempted to describe this bias using 4 speech-delayed children (aged 4 and 7 years) with normal hearing and no significant language delay. They were audiotaped at four points during therapy over a 12-18 month period using imitation of single words derived from the Assessment of the Intelligibility of Dysarthric Speech. Parents and a group of unfamiliar adult couples served as judges. Results indicated that mothers were significantly better than all other listeners (including fathers) at identifying the words being spoken. An interaction between listener type and subject age class was also observed with the maternal advantage being much less apparent with the 2 older subjects. Results are discussed relative to the possible source of the mothers' superior performance.