A joint interference effect in picture naming

In two experiments we provided evidence for a joint interference effect in picture naming. Participants took longer to name pictures when they believed that their partner concurrently named pictures than when they believed their partner was silent (Experiment 1) or concurrently categorized the pictures as being from the same or from different semantic categories (Experiment 2). However, picture naming latencies were not affected by beliefs about what one’s partner said. These findings are consistent with the idea that speakers represent whether another speaker is preparing to speak, but not what they are preparing to say.