Tracing attention and the activation flow of spoken word planning using eye movements.

The flow of activation from concepts to phonological forms within the word production system was examined in 3 experiments. In Experiment 1, participants named pictures while ignoring superimposed distractor pictures that were semantically related, phonologically related, or unrelated. Eye movements and naming latencies were recorded. The distractor pictures affected the latencies of gaze shifting and vocal naming. The magnitude of the phonological effects increased linearly with latency, excluding lapses of attention as the cause of the effects. In Experiment 2, no distractor effects were obtained when both pictures were named. When pictures with superimposed distractor words were named or the words were read in Experiment 3, the words influenced the latencies of gaze shifting and picture naming, but the pictures yielded no such latency effects in word reading. The picture-word asymmetry was obtained even with equivalent reading and naming latencies. The picture-picture effects suggest that activation spreads continuously from concepts to phonological forms, whereas the picture-word asymmetry indicates that the amount of activation is limited and task dependent.