Capacity limits for stimulus-response bindings

Executing a response results in associations between features of stimuli and the response stored in a temporary memory trace or ‘event file’. Reencountering any feature retrieves the entire event file which in turn affects performance in the current action episode. Event files not only include task-relevant features but also features from stimuli that are task-irrelevant but accompanying the target. So far, however, the potential capacity limit of an event file has been ignored. Are all irrelevant features integrated into event files? When transferring the concept of event files to everyday life situations, it becomes clear that this is very likely not the case. Thus, we investigated capacity limits for simultaneous bindings in three experiments (together N = 154) by testing capacity-related boundaries with different set sizes of polygon stimuli. Stimulus-response binding effects were observed for irrelevant polygon stimuli with small set sizes but not with larger set sizes. Our results suggest that (i) event files do have capacity limits and (ii) that these limits could be linked to filter or capacity theories of attention and short-term memory. • Actions create links between stimulus features and the response (S-R binding). • Irrelevant stimuli can also be bound to responses, but the limit has been unclear. • Irrelevant stimuli are bound only when the number of distractors is small. • S-R bindings have capacity limits, likely tied to attention and working memory.