Event files: Evidence for automatic integration of stimulus-response episodes

One of the main functions that visual attention serves in perception and action is feature binding; that is, integrating all information that belongs to an object. The outcome of this integration has been called "object file", a hypothetical memory structure coding episodic combinations of stimulus features. Action-oriented approaches to attention, however, suggest that such a purely perceptual or perceptually derived structure may be incomplete: If attention subserves action control, object files may include action-related Information as well. That is, feature binding may not be restricted to stimulus features but also include features of the responses made to the respective stimulus. In three experiments, subjects performed simple, already prepared left-or right-key responses (R1) to the mere presence of "Go" signals (S1) that varied randomly in farm, colour and location. Shortly after the prepared response, a binary choice reaction (R2) to the form or colour of a second stimulus (S2) was made. The results show that benefits due to stimulus-feature repetitions (S1-S2) interact: Form repetition only facilitates performance if colour is also repeated, and repeating the relevant stimulus feature (form or colour) only facilitates performance if stimulus location is repeated. This can be taken as evidence for object-file formation. But there was also evidence for bindings between stimulus and response features: Repetition benefits associated with both the relevant stimulus feature and stimulus location depended on response repetition. This suggests that object files represent only one component of more complex "event files" that link information about stimulus and response aspects of an experienced episode.