Retrieval of bindings between task-irrelevant stimuli and responses can facilitate behaviour under conditions of high response certainty

Repetition priming can be driven by the encoding and retrieval of stimulus-response (S-R) bindings. When a previously encoded S-R binding is retrieved, and is congruent with the response currently required, it can bias response-selection processes towards selecting the retrieved response, resulting in facilitation. Previous studies have used classification tasks at retrieval. Here, two (or more) response options are competing, and it is likely that any evidence (e.g., an S-R binding) in favour of one option will be utilized to effect a decision. Thus, S-R effects are likely to be seen when using such a task. It is unclear whether such effects can be seen under conditions of higher response certainty, when participants are explicitly cued to make a response. Across two experiments, evidence for a modulating influence of S-R bindings is seen despite using a response cueing method at retrieval to minimize response uncertainty and despite stimuli being task irrelevant. Finally, the results suggest that responses within these S-R bindings are coded at the level of left versus right hand, and not a more fine-grained within-hand thumb versus index finger. The results underline the resilience of S-R effects, suggesting that they are present even under conditions where no explicit object-oriented decision is required.