Ease of processing constrains the activation flow in the conceptual-lexical system during speech planning

In three picture-word interference experiments, speakers named a target object in the presence of an unrelated not-to-be-named context object. Distractor words, which were phonologically related or unrelated to the context object’s name, were used to determine whether the context object had become phonologically activated. All objects had high frequency names, and ease of processing of these objects was manipulated by a visual degradation technique. In Experiment 1, both objects were non-degraded, in Experiment 2 both objects were degraded, and in Experiment 3 either the target object or the context object was degraded. Distractor words, which were phonologically related to the context objects, interfered with the naming response when both objects were presented non-degraded, indicating that the context objects had become phonologically coactivated. The effect vanished, when both objects were degraded, when only the context object was degraded, and when only the target object was degraded. These data demonstrate that the amount of available processing resources constrains the forward-cascading of activation in the conceptual-lexical system. Context objects are likely to become phonologically coactivated, if they are easily retrieved and if prioritized target processing leaves sufficient resources.