Thematic role information is maintained in the visual object-tracking system

Thematic roles characterise the functions of participants in events, but there is no agreement on how these roles are identified in the real world. In three experiments, we examined how role identification in push events is supported by the visual object-tracking system. Participants saw one to three push events in visual scenes with nine identical randomly moving circles. After a period of random movement, two circles from one of the push events and a foil object were given different colours and the participants had to identify their roles in the push with an active sentence, such as red pushed blue. It was found that the participants could track the agent and patient targets and generate descriptions that identified their roles at above chance levels, even under difficult conditions, such as when tracking multiple push events (Experiments 1-3), fixating their gaze (Experiment 1), performing a concurrent speeded-response task (Experiment 2), and when tracking objects that were temporarily invisible (Experiment 3). The results were consistent with previous findings of an average tracking capacity limit of four objects, individual differences in this capacity, and the use of attentional strategies. The studies demonstrated that thematic role information can be maintained when tracking the identity of visually identical objects, then used to map role fillers (e.g., the agent of a push event) into their appropriate sentence positions. This suggests that thematic role features are stored temporarily in the visual object-tracking system.