Heart rate and respiration were monitored while the subject listened for the appearance of a target sentence in a subsequent block of text. In two-thirds of the trials, the target sentence was altered by major or minor changes in wording, and the subject was asked to indicate whether or not a change had occurred. Heart rate preceding the first appearance of correctly recognized target sentences showed a steeper acceleration than heart rate preceding incorrectly recognized sentences. Mean heart rate during the correctly recognized embedded sentences showed a steeper deceleration than was present when the wording change was not recognized. Respiration amplitude decreased significantly in the vicinity of the embedded sentence (perhaps reflecting some kind of ‘Ah-ha’ effect) but did not discriminate between hits and misses, and did not correlate with change of heart rate. It was concluded that falling heart rate may be triggered by a shift in style of listening set in motion when the subject attends more closely to the specific words in the sentence as opposed to its underlying meaning.