Douglas R. Hofstadter and Daniel C. Dennett
Publisher: Bantam Books (1982)

Consider, for example, the striking discovery by the psycholinguists James Lackner and Merril Garrett of what might be called an unconscious channel of sentence comprehension. In dichotic listening tests, subjects listen through earphones to two different channels and are instructed to attend to just one channel. Typically they can paraphrase or report with accuracy what they have heard through the attended channel but usually they can say little about what was going on concomitantly in the unattended channel. Thus, if the unattended channel carries a spoken sentence, the subjects typically can report they heard a voice, or even a male or female voice. Perhaps they even have a conviction about whether the voice was speaking in their native tongue, but they cannot report what was said. In Lackney and Garrett’s experiments subjects heard ambiguous sentences in the attended channel, such as “He put out the lantern to signal the attack.” Simultaneously, in the unattended channel one group of subjects received a sentence that suggested the interpretation of the sentence in the attended channel (e.g. “He extinguished the lantern), while another group had a neutral or irrelevant sentence as input. The former group could not report what was presented through the unattended channel, but they favoured the suggested reading of the ambiguous sentences significantly more than the control group did.