Contextual facilitation from attended and unattended messages

Listeners shadowed a list of words, a sentence, or a few words followed by the remainder of a sentence, and their shadowing latencies to the final word were recorded. The sentence or part of the sentence served to provide contextual information prior to the target word, and as the amount of context increased the shadowing latency to the final word decreased. Each presentation comprised a dichotic message, however, and the context was sometimes provided in the message not being shadowed—the unattended message. Unattended context did facilitate the shadowing response, but the extent of the facilitation was constant regardless of the amount of context. The effect of attended context was interpreted as a result of a strategical manipulation of response bias (a resource-limited process), whereas unattended context may be effective through spreading excitation in semantic memory (a data-limited process).