The effects of voice changes on orienting and immediate cognitive overloadin radio listeners

An experiment was designed to identify the voice change as a specific struc tural feature of radio that causes automatic allocation of cognitive resour ces to message encoding. The cardiac orienting response (OR) was used as an indication of this automatic resource allocation It was hypothesized that listeners would exhibit cardiac ORs in response to voice changes and that t he associated automatic resource allocation would result in momentary cogni tive overload. Data were collected from 62 participants as they listened to nine messages that varied in the number of voice changes they contained. R esults show robust cardiac orienting to voice changes and suggest that this response does not habituate over the course of 2-minute messages. Furtherm ore, auditory recognition data show that not only does orienting to voice c hanges result in momentary cognitive overload but the severity of that over load depends on the total number of voice changes in the message.