The power of words: On item-specific stimulus–response associations formed in the absence of action.
Résumé
Research on stimulus-response (S-R) associations as the basis of behavioral automaticity has a long history. Traditionally, it was assumed that S-R associations are formed as a consequence of the (repeated) co-occurrence of stimulus and response, that is, when participants act upon stimuli. Here, we demonstrate that S-R associations can also be established in the absence of action. In an item-specific priming paradigm, participants either classified everyday objects by performing a left or right key press (task-set execution) or they were verbally presented with information regarding an object's class and associated action while they passively viewed the object (verbal coding). Both S-R associations created by task-set execution and by verbal coding led to the later retrieval of both the stimulus-action component and the stimulus-classification component of S-R associations. Furthermore, our data indicate that both associations created by execution and by verbal coding are temporally stable and rather resilient against overwriting. The automaticity of S-R associations formed in the absence of action reveals the striking adaptability of human action control. Public Significance Statement Research on associative learning has shown that when we act upon stimuli-for instance, when we stop our car in front of a red traffic light-associations are formed between the respective stimuli (i.e., the red traffic light) and our actions (i.e., hitting the brake pedal). Due to these associations, previous actions are retrieved automatically when a stimulus recurs. That is, we do not need to elaborate on the action again and sometimes even reperform the same action contrary to our current intentions. Here, we provide evidence that acting upon stimuli is not necessary to associate stimuli and responses. Instead verbal information denoting action and stimulus classification presented simultaneously with a stimulus is apparently bound to it and supports the respective action when the stimulus is reencountered. These findings suggest that behavioral automaticity can be achieved without prior practice.